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1
Benson, Andrew James. "High-performance liquid chromatography (HPLC) and high-performance liquid chromatography mass spectrometry (HPLC/MS) for the analysis of date rape drugs." FIU Digital Commons, 2002. http://digitalcommons.fiu.edu/etd/1602.
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The drugs studied in this work have been reportedly used to commit drug-facilitated sexual assault (DFSA), commonly known as "date rape". Detection of the drugs was performed using high-performance liquid chromatography with ultraviolet detection (HPLC/UV) and identified with high performance-liquid chromatography mass spectrometry (HPLC/MS) using selected ion monitoring (SIM). The objective of this study was to develop a single HPLC method for the simultaneous detection, identification and quantitation of these drugs.
The following drugs were simultaneously analyzed: Gamma-hydroxybutyrate (GHB), scopolamine, lysergic acid diethylamide, ketamine, flunitrazepam, and diphenhydramine. The results showed increased sensitivity with electrospray (ES) ionization versus atmospheric pressure chemical ionization (APCI) using HPLC/MS. HPLC/ES/MS was approximately six times more sensitive than HPLC/APCI/MS and about fifty times more sensitive than HPLC/UV. A limit of detection (LOD) of 100 ppb was achieved for drug analysis using this method. The average linear regression coefficient of correlation squared (r2) was 0.933 for HPLC/UV and 0.998 for HPLC/ES/MS.
The detection limits achieved by this method allowed for the detection of drug dosages used in beverage tampering. This method can be used to screen beverages suspected of drug tampering.
The results of this study demonstrated that solid phase microextraction (SPME) did not improve sensitivity as an extraction technique when compared to direct injections of the drug standards.
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Walker, Roderick Bryan. "HPLC analysis and pharmacokinetics of cyclizine." Thesis, Rhodes University, 1995. http://hdl.handle.net/10962/d1003279.
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The investigations detailed in this dissertation have been conducted to address the paucity of pharmacokinetic information, in published literature, pertaining to cyclizine. The areas of investigation have included the selective quantitation of both cyclizine and its demethylated metabolite, norcyclizine in serum and urine, assessment of stability of both compounds in stored biological samples, dosage form analysis, dissolution rate testing of tablets, and bioavailability and pharmacokinetics following administration of an intravenous solution, and tablets to humans. High-performance liquid chromatography (HPLC) was used as the main analytical technique throughout these studies. An original HPLC method employing ultraviolet detection with a limit of quantitation of 5μg/ℓ was developed for the determination of cyclizine in serum and both cyclizine and norcyclizine in urine, Solid-phase extraction using extraction columns packed with reversed-phase C18 material, and followed by a simple phase-separation step proved successful for the accurate and precise isolation of the compounds. The validated method was applied to the analysis of serum and urine samples from a pilot study in which a single volunteer was administered 50mg of cyclizine hydrochloride. Several samples collected during the pilot study revealed the presence of both drug and metabolite in concentrations below the limit of detection. In order to improve the selectivity and sensitivity of the analytical method an HPLC method with electrochemical detection operating in the "oxidative-screen" mode was developed. The solid-phase extraction procedure was modified slightly and the method found to be precise, accurate, selective and highly sensitive with a limit of quantitation of Iμg/g/l for both cyclizine and norcyclizine in both serum and urine. This method was applied to the determination of both compounds after intravenous and oral administration of cyclizine to humans. HPLC with electrochemical detection was used for the analysis of samples collected during dissolution studies on the batch of tablets used for pharmacokinetic studies. In addition, this method was used to assess content uniformity of the tablets and of samples from the batch of intravenous ampoules of cyclizine lactate. Dissolution studies showed that all tablets tested passed the compendial specifications for cyclizine. Content uniformity assessment revealed that within-batch uniformity existed for both the tablets and ampoules and, therefore, variations in pharmacokinetic parameters for the drug would more than likely be as a result of inter- and intra-individual variability within the subject population. Pharmacokinetic information for cyclizine was obtained following administration of an intravenous bolus dose of cyclizine lactate as a solution, oral administration of cyclizine hydrochloride as a single dose of 50mg and as fixed multiple doses of 50mg every 8 hours for five days. Further information was acquired following administration of single doses of 100mg and 150mg cyclizine hydrochloride. Data collected from these studies were evaluated using both compartmental and non-compartmental techniques. Cyclizine was rapidly absorbed following oral administration with mean kₐ = 1.54 hr⁻¹ and was found to have an absolute bioavailability (F) of 0.47. The presence of norcyclizine in serum following oral and not intravenous dosing suggests cyclizine is susceptible to "first-pass" metabolism in either the gut wall or the I iver. Mean ClTOT determined following the intravenous dose was 0.865 ℓ/hr/kg. The mean ClTOT of 0.823 ℓ/hr/kg calculated following oral dosing, using a unique value of F for each subject compared favourahly with that obtained following intravenous dosing. Renal clearance of cyclizine is negligihle indicating that non-renal routes of elimination account for the majority of removal of cyclizine form the body. Cyclizine is extensively distributed and the mean Vz following an intravenous dose was 16.70 ℓ/kg. This value is lower than that calculated from all oral studies from which the mean Vz was determined to be 25.74 ℓ/kg. Cyclizine is eliminated slowly with a mean elimination t½ = 20.11 hours. Cyclizine dose not appear to follow dosedependent kinetics and therefore, inability to predict steady state levels are more than likely due to accumulation as a result of frequent dosing rather than saturation of elimination mechanisms. Modelling of intravenous data to one-compartment (lBCM), two-compartment (2BCM) and threecompartment models indicated that the pharmacokinetics of cyclizine can be adequately described by a 3BCM. The drug is rapidly distributed into a "shallow" peripheral compartment (α = 9.44 hr⁻¹ , and k₂₁ = 2.09 hr⁻¹ ), and slowly distributed to the "deep" peripheral compartment (β = 0.451 hr⁻¹ and k₃₁ = 0.120 hr⁻¹ ). Modelling of all oral data indicated that a 2BCM best described the pharmacokinetics of the drug, however, distribution to the peripheral compartment is not as rapid as to the "shallow" peripheral compartment following the intravenous dose. Mean distribution parameters were α = 0.64 hr⁻¹1 and, k₂₁ = 0.39 hr⁻¹. Mean CITOT following intravenous dosing of 0.70 ℓ/hr/kg was similar to the mean CIToT of 0.73 ℓ/hr/kg determined after oral dosing. The mean distribution volume at steady state determined following intravenous dosing (17.78 ℓ/kg) was lower than that obtained from the oral studies (25.52 ℓ/kg). The mean terminal elimination half-lives calculated for cyclizine following fitting of intravenous and oral data was 25.09 hours. In general, mean pharmacokinetic parameters calculated following titting of data to a 2BCM after oral administration correlate closely with those calculated using non-compartmental techniques. However, the pharmacokinetics following intravenous dosing are better described by a 3BCM and a close correlation between parameters estimated using noncompartmental techniques and compartmental techniques is evident when a 3BCM model is used.
3
Li, F. "Studies of haem biosynthesis and metabolism by high-performance liquid chromatography." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378943.
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Watson, Richard Charles. "Studies of reversed phase high performance liquid chromatography (RP-HPLC) stationary phases." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338492.
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Weddle, Carolyn A. "Optimization of HPLC techniques for separation of oxidized phosphatidylcholines." Virtual Press, 2005. http://liblink.bsu.edu/uhtbin/catkey/1319835.
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In cellular studies of patients with lipid related disorders such as mammary cancers, leukemia, and artheroscierosis, separation of molecular species of oxidized phosphatidylcholine (PC) can be an important assistance in research or diagnosis. Goals of this project were to optimize separation of oxidized and unoxidized PC molecular species in a single HPLC chromatogram followed by in line identification of hydroperoxides. Oxidized egg PC's were produced using UV light exposure in air. Separations were performed on an Ultrasphere ODS column and an Asahipak ODPVA column using a Waters 2695 system with photodiode array. The ODPVA column routinely gave 10 times larger plate numbers. Various mobile phase mixtures (methanol, acetonitrile, water) and gradients were tested. The optimum gradient on our system is (1) 5 minutes, 47 % methanol/40 % acetonitrile/13 water in a linear gradient to (2) 17 minutes, 49 % methanol/40 % acetonitrile/11 % water to (3) 18 minutes, 29 % methanol/60 % acetonitrile/11 % water linearly to (4) 50 minutes, 31 % methanol/60 % acetonitrile/9 % water continued isocratically to 110 minutes. Oxidized hydroperoxides were detected by fluorescence using a post column reaction with diphenyl-1 pyrenylphosphine (DPPP). Both iron (III) and pyridine were tested as catalysts for this reaction.<br>Department of Chemistry
6
Soor, Amritpal. "Group separation of complex mixtures by normal-phase high performance liquid chromatography and analysis by gas chromatography." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-64791.
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Ansong, Godfred. "Analysis of plant polyphenols by high performance liquid chromatography/mass spectrometry and protein binding." Oxford, Ohio : Miami University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1083081905.
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張雅茗. "營實HPLC指紋圖譜研究初探". HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1364.
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Murphy, Kellyann M. "Analysis of Biodiesel Quality Using Reversed Phase High-Performance Liquid Chromatography." Scholarship @ Claremont, 2012. http://scholarship.claremont.edu/pomona_theses/45.
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The alternative fuel biodiesel is produced from the transesterification of vegetable oils or animal fat to fatty acid methyl esters. Pomona has a reactor on campus that can be used to run this reaction and produce biodiesel. The use of biodiesel has been found to lower air pollutant and greenhouse gas emissions, but can be potentially harmful to the engines if it contains impurities. This paper proposes a method using high-performance liquid chromatography to test the quality of biodiesel. This method utilizes instrumentation and materials that are available in Pomona College's Chemistry Department, requires very little sample preparation, and is relatively safe, as long as general lab safety practices are followed. This method can also be used to optimize the procedure used to make the biodiesel. An optimized production procedure and a test method to assess the final product will ensure high quality fuel that can be used with confidence in diesel engines. This will likely add strength to proposals to increase the use of the on-campus reactor and produce biodiesel for campus grounds equipment from waste vegetable oil.
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Huyghues-Despointes, Alexis. "Synthesis, characterization, and approaches to the analysis by HPLC-THG-AAS of trimethylselenonium, selenoniumcholine and selenoniumacetylcholine cations." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59977.
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Selenonium cations are electron deficient species in which the central selenium atom is bonded to three carbon chains (aryl or alkyl). Trimethylselenonium iodide was synthesized by reaction of methyllithium with metallic selenium to produce methylselenolithium which was, in turn, reacted with the appropriate alkylbromide. The selenide thus formed was further methylated at the selenium atom with methyl iodide in methanol in the presence of sodium tetraphenylborate. After several recrystallizations the selenonium analytes were characterized by AAS, FT-IR, $ sp1$H-NMR, $ sp{13}$C-NMR, FAB-MS and LAMMA spectroscopic techniques and used as standards for analytical methods development.<br>The analysis was performed by high performance liquid chromatography with atomic absorption detection. The chromatography on a cynopropyl silica bonded phase was optimized for mobile phase composition by response surface analysis. The resulting surface response plots permitted a differentiation between the mechanisms of action of two mobile phase modifiers: triethylamine and trimethylsulfonium iodide. The improvement in chromatographic efficiency resulted in two to three fold decrease in the limit of detection. An extraction procedure with liquefied phenol was evaluated for the determination, by HPLC-AAS, of traces of selenonium cations in biological samples. The advantages and shortcomings of the HPLC-THG-AAS approach are discussed.
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Bottegal, Megan N. "The Development of High Performance Liquid Chromatography Systems for the Analysis of Improvised Explosives." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/154.
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Existing instrumental techniques must be adaptable to the analysis of novel explosives if science is to keep up with the practices of terrorists and criminals. The focus of this work has been the development of analytical techniques for the analysis of two types of novel explosives: ascorbic acid-based propellants, and improvised mixtures of concentrated hydrogen peroxide/fuel. In recent years, the use of these explosives in improvised explosive devices (IEDs) has increased. It is therefore important to develop methods which permit the identification of the nature of the original explosive from post-blast residues. Ascorbic acid-based propellants are low explosives which employ an ascorbic acid fuel source with a nitrate/perchlorate oxidizer. A method which utilized ion chromatography with indirect photometric detection was optimized for the analysis of intact propellants. Post-burn and post-blast residues if these propellants were analyzed. It was determined that the ascorbic acid fuel and nitrate oxidizer could be detected in intact propellants, as well as in the post-burn and post-blast residues. Degradation products of the nitrate and perchlorate oxidizers were also detected. With a quadrupole time-of-flight mass spectrometer (QToFMS), exact mass measurements are possible. When an HPLC instrument is coupled to a QToFMS, the combination of retention time with accurate mass measurements, mass spectral fragmentation information, and isotopic abundance patterns allows for the unequivocal identification of a target analyte. An optimized HPLC-ESI-QToFMS method was applied to the analysis of ascorbic acid-based propellants. Exact mass measurements were collected for the fuel and oxidizer anions, and their degradation products. Ascorbic acid was detected in the intact samples and half of the propellants subjected to open burning; the intact fuel molecule was not detected in any of the post-blast residue. Two methods were optimized for the analysis of trace levels of hydrogen peroxide: HPLC with fluorescence detection (HPLC-FD), and HPLC with electrochemical detection (HPLC-ED). Both techniques were extremely selective for hydrogen peroxide. Both methods were applied to the analysis of post-blast debris from improvised mixtures of concentrated hydrogen peroxide/fuel; hydrogen peroxide was detected on variety of substrates. Hydrogen peroxide was detected in the post-blast residues of the improvised explosives TATP and HMTD.
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Hayteas, David Lawrence. "HPLC analysis of myoglobin tryptic peptides from selected species of cetaceans." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/4086.
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Due to the large gaps in the fossil record, the evolutionary history of the mammalian order Cetacea is incomplete and controversial. Increasingly researchers are utilizing molecular and biochemical procedures to supplement cetacean paleontology. One of these methods is the comparison of amino acid sequences of myoglobin among species of this order. since this method is time-consuming and expensive, an alternative procedure is desirable.
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Li, Cheuk Fai. "Studies of flow injection system for micelle-assisted preconcentration of PAHs coupled with HPLC." HKBU Institutional Repository, 2009. http://repository.hkbu.edu.hk/etd_ra/1059.
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Wang, Tongwen. "Hyphenated HPLC-MS technique for analysis of compositional monosaccharides of transgenic corn glycoprotein and characterization of degradation products of diazinon, fonofos and aldicarb in various oxidation systems." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/WangTongwen_09007dcc804e975c.pdf.
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Thesis (Ph. D.)--University of Missouri--Rolla, 2007.<br>Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 23, 2008) Includes bibliographical references.
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Perdue, James D. "The removal of Cremophor® EL from paclitaxel for quantitative analysis by HPLC-UV /." Electronic version (PDF), 2005. http://dl.uncw.edu/etd/2005/perduej/jamesperdue.pdf.
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Kamble, Ujjwala Kerba. "Use of liquid chromatography for assay of flavonoids as key constituents and antibiotics as trace elements in propolis : investigation into the application of a range of liquid chromatography techniques for the analysis of flavonoids and antibiotics in propolis, and extraction studies of flavonoids in propolis." Thesis, University of Bradford, 2016. http://hdl.handle.net/10454/14564.
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Propolis is an approved food additive containing flavonoids as a major active constituent. Variability has been found in the composition of propolis in distinctive regions and it was noticed that there are limitations in the analysis of propolis. In this study, the identification of ten flavonoids and residual antibiotics in propolis was investigated by using several liquid chromatography techniques, including reversed-phase high-performance liquid chromatography (RP-HPLC), microemulsion LC (MELC) and ultra-performance LC (UPLC). The ten flavonoids that were selected for this research include rutin, myricetin, quercetin, apigenin, kaempferol, pinocembrin, CAPE, chrysin, galangin and acacetin while chlortetracycline, oxytetracycline and doxycycline were selected to examine the residual antibiotics in propolis. For the analysis of the selected flavonoids, routine RP-HPLC method was found to be the best method, while MELC technique was found more efficient for the analysis of the selected antibiotics. Solid phase extraction with HLB sorbent was utilised in the analysis of antibiotics for clean-up of propolis. In method development studies for flavonoids and antibiotics, one-factor-at-a-time (OFAT) approach was followed. The final optimised method for the analysis of flavonoids as well as the method. for the analysis of antibiotics was validated using the ICH guidelines, and various aspects, such as the linearity, selectivity, accuracy, recovery, robustness and stability parameters, were examined. Development of efficient conventional method for the extraction of flavonoids from propolis was studied extensively in the present research work using different extraction techniques such as maceration, hot extraction, ultrasound assisted extraction. Among all extraction experiments, ethanolic extraction using ultrasound extraction method was the best efficient approach. This thesis shows that, in general, the performance of O/W MELC is superior to that of conventional HPLC for the determination of residual antibiotics in propolis. UPLC was not suitable for the analysis of flavonoids and antibiotics. The conventional LC was the only technique to separate the ten flavonoids but MELC was able to separate nine of the flavonoids with faster analysis time. This work also showed that MELC uses cheaper solvents. This considerable saving in both cost and time will potentially improve efficiency within quality control.
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Brannegan, Daniel Robert. "Analysis of Ethoxyquin and its Oxidation Products using Supercritical Fluid Extraction and High Performance Liquid Chromatography with Chemiluminescent Nitrogen Detection." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/31575.
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Ethoxyquin is an antioxidant commonly used to preserve vitamins and lipids in various food products and animal feeds. The extraction and determination of ethoxyquin is becoming increasingly important as products, which are labeled as "natural" are becoming more common. The present method of determination only ensures that ethoxyquin values are below 10-20 parts per million. Therefore, advances are needed in methods of extraction and analysis in order to lower the detection limits in various products.
The first part of this research investigates the use of supercritical fluids in the extraction of ethoxyquin from lean beef and beef fat. Supercritical fluids offer the advantages of safety, time, expense, and selectivity over liquid extractions. Three fluids were examined: carbon dioxide, trifluoromethane, and 1,1,1,2-tetrafluoroethane. Carbon dioxide appeared to react with ethoxyquin during the extraction. Methanol modified hydrofluorocarbons provided more complete extractions over pure hydrofluorocarbon fluids. Methanol modified 1,1,1,2-tetrafluoroethane was used in the extraction of ethoxyquin from lean beef and beef fat, and provided a quantitative extraction at the 0.5 ppm level.
The second part of this research centered on the separation and quantitation of the oxidation products of ethoxyquin through the use of high pressure liquid chromatography with chemiluminescence nitrogen detection (HPLC/CLND). When ethoxyquin is oxidized, the resulting products also exhibit antioxidative properties. While these oxidation products are known, no effort has been made to separate and quantify them in real or clean samples. HPLC/CLND allows all nitrogen containing compounds to be quantified without a known standard. This method is of extreme interest in the case of ethoxyquin oxidation products, or other types of metabolites, where standards are difficult to obtain or are unstable. HPLC/CLND allowed a separation of ethoxyquin and four of its oxidation products to be detected, thus making future studies of the antioxidant behavior of ethoxyquin feasible.<br>Master of Science
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Rösemann, G. M. "Analysis of pyrrolizidine alkaloids in Crotalaria species by HPLC-MS/MS in order to evaluate related food health risks." Electronic thesis, 2006. http://upetd.up.ac.za/thesis/available/etd-08032007-170633/.
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Nestola, Marco [Verfasser], and Torsten Claus [Akademischer Betreuer] Schmidt. "Multidimensional high-performance liquid chromatography–gas chromatography (HPLC-GC) hyphenation techniques for food analysis in routine environments / Marco Nestola ; Betreuer: Torsten Claus Schmidt." Duisburg, 2016. http://d-nb.info/1115654659/34.
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Pinto, Angela Marie III. "Quantitative Analysis of Antioxidants from High Density Polyethylene (HDPE) by off-line Supercritical Fluid Extraction Coupled High Performance Liquid Chromatography." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36932.
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Plastics are widely used and they vary in their applicability, ranging from automobile parts, components for houses and buildings, and packaging for everything from food to electronic parts. The diverse applications of plastics, such as polystyrene, polyolefins and polyester, are credited to the incorporation of additives. Additives improve the performance of these and other polymer resins. Without the incorporation of such additives, for example Ethanox ® 330, some plastics would degrade during processing or over time. To ensure that the specified amount of an additive or combination of additives are incorporated into a polymer after the extrusion process, a rapid and accurate analytical method is required. Quantitation of additive(s) in the polymer is necessary, since the additive(s) may degrade and the amount of additive(s) can influence the physical nature of the polymer. Conventional extraction techniques for polymer additive(s), such as, Soxhlet or dissolution / precipitation are labor intensive, time consuming, expensive, and the optimal recovery is significantly less than 90 percent. In addition, a large amount of solvent , such as toluene or decalin, must be eliminated in order to concentrate the sample prior to chromatographic separation.
<P>Supercritical Fluid Extraction (SFE) has been employed as an alternative polymer preparation technique. SFE is a favorable means for various analytical sample preparation applications, credited to its short extraction times. This research employs SFE for the extraction of the antioxidant Ethanox® 330 from high density polyethylene (HDPE) followed by HPLC/UV analysis. The effects of temperature, modifier type, and modifier concentration were investigated. Once the optimal extraction conditions were determined, the extraction efficiency of Ethanox ® 330 as a single additive and in the presence of co-additives from HDPE were investigated. Recoveries of greater than 90% were obtained for Ethanox ® 330 when a secondary antioxidant was present in the HDPE.<br>Master of Science
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Krenz, Robert J. "Photopigments as descriptors of phytoplankton assemblages for biotic assessment of Illinois lakes and reservoirs : an HPLC aided analysis /." View online, 2009. http://repository.eiu.edu/theses/docs/32211131592143.pdf.
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Mills, Heidi Clare Maria. "Development of a Method of Analysis by High Performance Liquid Chromatography for Products of the Nitric Acid Oxidation of D-Glucose." The University of Waikato, 2007. http://hdl.handle.net/10289/2517.
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This thesis explored the development of a faster and more efficient means of qualitative and quantitative analysis of the products of the nitric acid oxidation of D-glucose and other simple sugars, for the Shafizadeh Rocky Mountain Center for Wood and Carbohydrate Chemistry. During the research, analysis was carried out based on previous work completed in a similar area using two Aminex HPX-87H+ cation-exchange columns at different temperatures, and plumbed in series. Standards were filtered and injected on to the columns, then eluted with 5 mM sulfuric acid. A total run time of 33 minutes enabled the elution of all products and by-products of the reaction. Retention times of standards and the use of spiking helped specify and quantify unknowns in samples from a series of oxidation reactions involving D-glucose and other aldoses. The PrevailTM Organic acid (OA) column was said to provide 'unsurpassed resolution of organic acids'. It was therefore investigated, and a method was developed and refined in order to optimise conditions enabling the column's use for the required analyses. The optimised parameters were established as: ambient temperature with an eluent of 10 mM KH2PO4 adjusted to a pH of 2.1 with phosphoric acid. The sample size was 5 uL with a flow rate of 0.3 mL/min, giving a total run time of approximately 13 minutes. The Aminex HPX-87H+ column method and the PrevailTM OA method were compared to determine the superior method for the analyses intended. While some improvements were made for detection in the PrevailTM OA method, results were not satisfactory. This was due in part to limits imposed on the PrevailTM OA column method, which prevented the use of gradient elution. The Aminex HPX-87H+ column method outlined herein provides superior resolution for the nitric acid oxidation of D-glucose to D-glucaric acid, and in conclusion it is suggested that the Aminex HPX-87H+ column method be used.
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Troalen, Lore Gertrud. "Historic dye analysis : method development and new applications in cultural heritage." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/11717.
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A review of the main natural dyes (particularly yellow flavonoids and red anthraquinones) and proteinaceous substrates used in Historical Tapestries and North American porcupine quill work was undertaken, and is summarised in Chapter 1. The analysis of natural dyes which have been used on museum artefacts other than textiles has received little systematic study, particularly those of non-European origin. In this research, the use of Ultra Performance Liquid Chromatography (UPLC) for study of natural dyes found on historical textiles and ethnographical objects decorated with porcupine quill work is explored; this required a transfer of existing analytical protocols and methodology. The advantages of using Ultra Performance Liquid Chromatography (UPLC) was evaluated through a method development based on the separation and quantification of ten flavonoid and anthraquinone dyes as described in Chapter 2. These methods were then applied to the characterisation of the dye sources found on a group of sixteenth century historical tapestries which form an important part of the Burrell Collection in Glasgow and are believed to have been manufactured in an English workshop (Chapter 3) and also to the analysis of some late nineteenth century North American porcupine quill work from a collection owned by National Museums Scotland (Chapter 5); allowing exciting conclusions to be drawn in each case about the range of dyestuffs used in their manufacture. The second aim of this research was the development of methodology for the non-invasive quantification of metal ion residues on porcupine quill substrates. This was achieved through a comparative study of reference porcupine quills prepared in-house with dyebaths containing a range of metal ion concentrations (copper and tin). The concentration of metal ions sorbed by the porcupine quills was then quantified with Inductively Coupled Plasma (ICP) coupled to Optical Emission Spectrometry (OES) and non-invasive Particle Induced X-Ray Emission analysis (PIXE) coupled with Rutherford Backscattering Spectrometry (RBS) as described in Chapter 4. The responses provided by the different methods were compared and they were then applied to the study of micro-samples collected from mid-nineteenth century Northern Athapaskan porcupine quill work. Unexpectedly, the use of UPLC analysis and RBS-PIXE analysis allowed the characterisation of traded European natural dyes used with metallic mordants (copper and tin) on these samples, highlighting how European contact impacted on traditional Athapaskan porcupine quill work in the late nineteenth century (Chapter 5).
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Arroyo-Mora, Luis. "Environmental analysis of polar herbicides in complex organic-rich matrices by high performance liquid chromatography atmospheric pressure ionization mass spectrometry (HPLC-API-MS)." FIU Digital Commons, 2003. http://digitalcommons.fiu.edu/etd/1425.
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A comprehensive forensic investigation of sensitive ecosystems in the Everglades Area is presented. Assessing the background levels of contamination in these ecosystems represents a vital resource to build up forensic evidence required to enforce future environmental crimes within the studied areas. This investigation presents the development and validation of a fractionation and isolation method for two families of herbicides commonly applied in the vicinity of the study area, including phenoxy acids like 2,4-D, MCPA, and silvex; as well as the most common triazine-based herbicides like atrazine, prometyne, simazine and related metabolites like DIA and DEA. Accelerated solvent extraction (ASE) and solid phase extraction (SPE) were used to isolate the analytes from abiotic matrices containing large amounts of organic material. Atmospheric-pressure ionization (API) with electrospray ionization in negative mode (ESP-), and Chemical Ionization in the positive mode (APCI+) were used to perform the characterization of the herbicides of interest.
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LEBRE, DANIEL T. "Desenvolvimento de metodologia para a determinacao de herbicidas e inseticidas em aguas superficiais utilizando extracao liquido-solido e cromatografia liquida de alta eficiencia." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10809.
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Schulze, Alexandra Elizabeth. "HPLC method development for characterisation of the phenolic composition of Cyclopia subternata and C. maculata extracts and chromatographic fingerprint analysis for quality control." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85773.
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Thesis (MScFoodSc)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: The phenolic composition of Cyclopia species is believed to be partially responsible for the numerous health
promoting properties associated with their extracts. Current quality control measures do not accommodate
variation in phenolic profiles of Cyclopia species. In this study, comprehensive high performance liquid chromatography
(HPLC) methods were developed for the improved characterisation of the phenolic composition of
aqueous extracts of two Cyclopia species (C. subternata and C. maculata). The methods were developed to be
suitable for both routine quantitative analysis on conventional HPLC instrumentation, and the construction of
chromatographic fingerprints for further data analysis. The latter entailed similarity analysis and prediction of
total antioxidant capacity (TAC).
Using a methodical approach, two separate HPLC methods, using diode array detection (DAD), were developed
and validated for the analysis of aqueous extracts prepared from unfermented (green) and fermented
plant material of C. subternata and C. maculata. Separation was achieved using the same method parameters
(column, temperature, mobile phases), except for differing mobile phase gradients. Hyphenation of
the developed HPLC methods with mass spectrometry (MS) and tandem MS allowed the confirmation of
phenolic compounds previously identified in Cyclopia, and the tentative identification of several additional
compounds in Cyclopia species, which are reported here for the first time. These included apigenin-6,8-di-
C-glucoside, 3-hydroxyphloretin-30,50-di-C-hexoside, eriodictyol-di-C-glucoside, iriflophenone-di-O,C-hexoside,
hydroxymangiferin and hydroxyisomangiferin. Subsequently, a large number of aqueous extracts of randomly
selected green C. subternata (n = 64) and C. maculata (n = 50) plant material samples were analysed. Large
quantitative variations were observed on intra- and inter-species levels. Cyclopia maculata extracts contained
almost six times more mangiferin than extracts from C. subternata.
HPLC-DAD analysis produced duplicate fingerprints for each extract which were consequently used for
further analysis. The chromatographic fingerprint of a bioactive extract of each species was included in the
respective data sets. Similarity analysis was conducted between the fingerprints from the randomly selected
extracts and the corresponding active extract. For each species several extracts were determined to have similar
“activity” as that of the active extract (n = 15 for C. subternata and n = 45 for C. maculata). Compounds
potentially responsible for the activity were tentatively identified with the aid of principal component analysis
(PCA) in combination with similarity analysis. PCA was more effective in identifying small differences between
fingerprints than similarity analysis based on the correlation coefficients (r) alone.
Furthermore, multivariate data analysis was used to construct partial least squares (PLS) regression models
for the prediction of TAC from fingerprint data of each species, and available data from two microplate TAC
assays. The construction of the models was successful with reasonable errors (< 10%), and permitted the
determination of compounds of interest for future research. These included compounds of known identity that
had large positive contributions toward the predictions of TAC, or unknown compounds that had small UV signals, but relatively large positive contributions to the models.<br>AFRIKAANSE OPSOMMING: Die talle gesondheidbevorderingseienskappe van ekstrakte van Cyclopia spesies word gedeeltelik geassosieer met
hul fenoliese samestelling. Huidige kwaliteitskontrolemaatreëls is nie in staat om die variasie wat in die fenoliese
profiele van die spesies voorkom, te akkommodeer nie. Omvattende hoë druk vloeistof chromatografiese (HPLC)
metodes is vir twee Cyclopia spesies, naamlik C. subternata en C. maculata, in hierdie studie ontwikkel vir beter
karakterisering van die fenoliese samestelling van waterekstrakte van dié spesies. Die metodes moes ook geskik
wees vir roetine analise van C. subternata en C. maculata ekstrakte op konvensionele HPLC instrumentasie,
en vir die opstel van chromatografiese vingerafdrukke (fenoliese samestellingsprofiele) vir verdere data analise,
soos gelykvormigheidsanalise en die voorspelling van die totale antioksidantkapasiteit (TAC).
Twee HPLC metodes, wat van ’n ultraviolet-diode detektor (DAD) gebruik maak, is ontwikkel deur ’n
sistematiese benadering te volg. Die onderskeie metodes is vir die ontleding van waterekstrakte van groen (ongefermenteerde)
en gefermenteerde plantmateriaal van C. subternata en C. maculata gevalideer. Ongeag die
spesie is optimale skeiding met dieselfde kolom, mobiele fase en kolom-temperatuur bereik, maar met verskillende
mobiele fase gradiënte. Analise met massaspektrometrie (MS) en tandem MS het die teenwoordigheid
van fenoliese verbindings, wat voorheen in Cyclopia spesies geidentifiseer is, bevestig. Verder is ook ’n aantal
verbindings vir die eerste keer in Cyclopia tentatief geidentifiseer. Dit sluit apigenien-6,8-di-C-glukosied, 3-
hidroksiefloretien-30,50-di-C-heksosied, eriodiktiol-di-C-glukosied, iriflofenoon-di-O,C-heksosied, hidroksiemangiferien
en hidroksie-isomangiferien in. Vervolgens is ’n groot aantal ewekansig gekose waterekstrakte van beide
groen C. subternata (n = 64) en C. maculata (n = 50) plantmateriaal geanaliseer, en groot kwantitatiewe variasie
op intra- en inter-spesievlak waargeneem. Cyclopia maculata ekstrakte het byvoorbeeld byna ses maal die
mangiferieninhoud van C. subternata ekstrakte gehad.
HPLC-DAD analise van die ekstrakte het duplikaat vingerafdrukke van elke ekstrak geproduseer, wat vir
verdere data analise gebruik is. Die chromatografiese vingerafdruk van ’n bioaktiewe ekstrak van elke spesie
was by die onderskeie datastelle ingesluit. Gelykvormigheidsanalise is tussen vingerafdrukke van die ewekansig
gekose ekstrakte en die ooreenstemmende aktiewe ekstrak uitgevoer. Vir elke spesie is ’n aantal “aktiewe”
ekstrakte aangewys (n = 15 vir C. subternata en n = 45 vir C. maculata). Die verbindings wat potensieel
verantwoordelik kan wees vir die aktiwiteite is met behulp van hoofkomponentontleding (PCA) in kombinasie
met gelykvormigheidsanalise, tentatief aangewys. PCA was egter meer effektief om klein verskille tussen vingerafdrukke
aan te dui, in vergelyking met gelykvormigheidsanalise wat slegs op die korrelasie koëffisiënt (r)
gebaseer is.
Meerveranderlike data analiese is gebruik om “gedeeltelike kleinste kwadrate” (PLS) regressiemodelle, vir
die voorspelling van die TAC van beide spesies te bou. Die voorspelling is gebaseer op hul vingerafdruk data en
TAC data van twee TAC mikroplaat metodes. Die model-konstruksie was suksesvol met aanvaarbare voorspellingsfoute
(< 10%). Verbindings van belang kon ook bepaal word. Dit sluit bekende verbindings in wat groot positiewe bydraes ten opsigte van die voorspelling van TAC getoon het, asook ongeidentifiseerde verbindings
wat klein UV-seine getoon het, maar relatiewe groot bydraes tot die modelle gehad het.
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Dubber, Mary-Jean. "Application of CE, HPLC and LC-MS-MS for the analysis and quality control of Ginkgo biloba dosage forms." Thesis, Rhodes University, 2006. http://hdl.handle.net/10962/d1003235.
Full textAbstract:
Natural products are complex mixtures of compounds with therapeutic effects which are often reported to be due to the synergistic action of multiple and sometimes unknown components. Consequently, standardization of these products is complex and a lack of effective quality control (QC) criteria in most countries has led to marketing of commercial products with questionable quality, safety and efficacy (QSE). The aim of this study was therefore to develop qualitative and quantitative analytical methods for use in the QC of Ginkgo biloba solid oral dosage forms. Initially, a micellar electrokinetic chromatography (MEKC) method was developed for the identification of the flavonol glycosides, rutin and quercitrin as well as 3 flavonol aglycones, quercetin, kaempferol and isorhamnetin in crude extracts of 4 Ginkgo biloba solid oral dosage forms using ultraviolet (UV) detection. A reversed-flow cyclodextrin-modified MEKC method was subsequently developed for the simultaneous determination of the aforementioned flavonols as well as ginkgolide A, B, C, J and bilobalide (all positive markers) in Ginkgo commercial products. A non-aqueous capillary electrophoresis (CE) method was also developed for fingerprinting the presence of ginkgolic acids (negative markers) in Ginkgo biloba leaf extracts, which are purported to be associated with toxic properties. This method was also applied to 2 Ginkgo biloba commercial products. Since the flavonols have strong UV absorbing chromophores, a reversed phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated using photo-diode-array (PDA) detection which was then successfully applied to fingerprint commercially available Ginkgo biloba solid oral dosage forms as well as quantify the relevant flavonol markers present in these extracts. Sample preparation was simple, rapid and cost efficient with minimal clean-up and the employment of a minibore column which requires low mobile phase flow rates contributed to the economy of the method. Unlike the conventional QC approach, samples were not hydrolyzed and direct determination of 2 intact flavonol glycosides, together with the usual aglycone markers was facilitated which provided maximal content information for fingerprint comparisons. On the other hand, terpene trilactones possess poor chromophores and an alternative detection method to UV was required in order to obtain suitable sensitivity. RP-HPLC with evaporative light scattering detection (ELSD) was selected for quantification of these non-volatile constituents in Ginkgo dosage forms and this method was deemed suitable for the routine QC analysis of these positive markers in commercial products. Since approximately 33 flavonoids have been identified in Ginkgo biloba leaf extracts, baseline separation using UV/PDA detection normally requires complex gradient programs and long analysis times. In addition, unequivocal identification of the flavonoids with similar UV spectra and elution times cannot be guaranteed. A liquid chromatographic tandem mass spectrometric (LC-MS-MS) method was therefore developed and validated in order to ensure accurate quantification of the selected flavonol marker compounds in Ginkgo commercial products. LC-MS-MS analysis of Ginkgo extracts revealed, in addition to rutin, the possible presence of other quercetin analogues, quercetin-3-Orhamnoside-7-O-glucoside or quercetin-3-O-glucoside-7-O-rhamnoside, previously unreported in Ginkgo biloba leaf extracts or dosage forms. In terms of evaluating the most suitable analytical method for QC, CE shows exceptional potential in the future analysis of Ginkgo biloba dosage forms while HPLC-PDA and HPLC-ELSD are currently the most affordable and practical instruments for the routine analysis of the flavonols and terpenoids, respectively. LC-MS-MS proved to be pivotal for the accurate identification and quantification of the flavonols due to interference by other flavonoid compounds with similar retention times and UV spectra to the peaks of interest. All quantitative and qualitative results revealed large discrepancies in the marker content between the products regardless of which batch was analysed and product labels disclosed little relevant information. Although currently not required by most regulatory agencies, some of the usual quality criteria applied to orthodox medicines was evaluated. In particular, dissolution analysis, disintegration, tablet hardness and weight uniformity were assessed and revealed similar inconsistencies. This thesis emphasises that implementation of effective QC criteria is long overdue and is essential to ensure consistent product QSE of commercially available Ginkgo biloba solid oral dosage forms.
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Viljoen, Francois Petrus. "Quantification of 3-methoxy-4-hydroxyphenylglycol in human saliva by an optimised HPLC method with electrochemical detection." Thesis, Bloemfontein : Central University of Technology, Free State, 2011. http://hdl.handle.net/11462/17.
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PEDREIRA, FILHO WALTER dos R. "Determinacao de impurezas metalicas em oxidos de terras raras de alta pureza pela espectrometria de massa (setor magnetico) com fonte de plasma induzida por argonio (HR ICP-MS) e cromatografia liquida de alto desempenho (HPLC)." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10904.
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Made available in DSpace on 2014-10-09T12:45:21Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:06:26Z (GMT). No. of bitstreams: 1
07290.pdf: 4641586 bytes, checksum: f9e82ba22fb397706f6ac72a5f266c6c (MD5)<br>Tese (Doutoramento)<br>IPEN/T<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Lindholm, Johan. "Development and Validation of HPLC Methods for Analytical and Preparative Purposes." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4442.
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Jolley, Bianca. "Development of quality control tools and a taste prediction model for rooibos." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95991.
Full textAbstract:
Thesis (MScFoodSc)--Stellenbosch University, 2014.<br>ENGLISH ABSTRACT: In this study quality control tools were developed for the rooibos industry, primarily to determine the quality of rooibos infusions. A considerable variation between samples of the same quality grade has been noted. As there are no guidelines or procedures in place to help minimise this inconsistency it was important to develop quality control tools, which could confront this problem. Both the sensory characteristics and phenolic composition of rooibos infusions were analysed in order to create and validate these quality control tools.
Descriptive sensory analysis was used for the development of a targeted sensory wheel and sensory lexicon, to be used as quality control tools by the rooibos industry, and to validate the major rooibos sensory profiles. In order to ensure all possible variation was taken into account, 230 fermented rooibos samples were sourced from the Northern Cape and Western Cape areas within South Africa over a 3-year period (2011-2013). The aroma, flavour, taste and mouthfeel attributes found to associate with rooibos sensory quality were validated and assembled into a rooibos sensory wheel, which included the average intensity, as well as the percentage occurrence of each attribute. Two major characteristic sensory profiles prevalent within rooibos, namely the primary and secondary profiles, were identified. Both profiles had a sweet taste and an astringent mouthfeel, however, the primary sensory profile is predominantly made up of “rooibos-woody”, “fynbos-floral” and “honey” aroma notes, while “fruity-sweet”, “caramel” and “apricot” aroma notes are the predominant sensory attributes of the secondary profile.
The predictive value of the phenolic compounds of the infusions towards the taste and mouthfeel attributes (“sweet”, “sour”, “bitter” and “astringent”) was examined using different regression analyses, namely, Pearson’s correlation, partial least squares regression (PLS) and step-wise regression. Correlations between individual phenolic compounds and the taste and mouthfeel attributes were found to be significant, but low. Although a large sample set (N = 260) spanning 5 years (2009-2013) and two production areas (Western Cape and Northern Cape, South Africa) was used, no individual phenolic compounds could be singled out as being responsible for a specific taste or mouthfeel attribute. Furthermore, no difference was found between the phenolic compositions of the infusions based on production area, a trend that was also seen for the sensory characterisation of rooibos infusions. Sorting, a rapid sensory profiling method was evaluated for its potential use as a quality control tool for the rooibos industry. Instructed sorting was shown to successfully determine rooibos sensory quality, especially based on the aroma quality of the infusions. However, determining the quality of the infusion based on flavour quality was more difficult, possibly due to the low sensory attribute intensities. Categorisation of rooibos samples based on the two major aroma profiles i.e. the primary and secondary characteristic profiles, was achieved with uninstructed sorting. The potential of using sorting as a rapid technique to determine both quality and characteristic aroma profiles, was therefore demonstrated, indicating its relevance as another quality control tool to the rooibos industry.<br>AFRIKAANSE OPSOMMING: Gehaltebeheer hulpmiddels is as deel van hierdie studie vir die rooibosbedryf ontwikkel, hoofsaaklik om die sensoriese kwaliteit van rooibostee te bepaal. Aansienlike verskille is tussen monsters van dieselfde gehaltegraad opgemerk, primêr omdat daar in die wyer rooibosbedryf beperkte riglyne of prosedures in plek is om kwaliteitsverskille effektief te bepaal. Dit is as belangrik geag om gehaltebeheer hulpmiddels te ontwikkel om laasgenoemde probleem aan te spreek. Spesifieke gehaltebeheer hulpmiddels is dus vir hierdie studie ontwikkel en gevalideer deur die sensoriese eienskappe en fenoliese samestelling van rooibostee te analiseer.
Beskrywende sensoriese analise (BSA) is gebruik om ‘n sensoriese wiel en leksikon vir die rooibosbedryf te ontwikkel en te valideer. Om alle moontlike produkvariasie te ondervang, is 230 gefermenteerde rooibos monsters afkomstig van die Noord-Kaap en Wes-Kaap areas in Suid-Afrika oor ‘n tydperk van drie jaar (2011-2013) verkry. Die aroma, geur, smaak en mondgevoel eienskappe wat met rooibos se sensoriese kwaliteit assosieer, is bevestig en uiteindelik gebruik om die sensoriese wiel te ontwikkel. Die gemiddelde intensiteit en persentasie voorkoms van elke eienskap is in die wiel ingesluit. Twee belangrike “karakteristieke” sensoriese profiele wat met rooibos geassosieer word, is geïdentifiseer, nl. die primêre en sekondêre sensoriese profiele. Tipies van beide sensoriese profiele is ‘n kenmerkende soet smaak en vrank mondgevoel, daarenteen bestaan die primêre sensoriese profiel hoofsaaklik uit "rooibos-houtagtige", "fynbos-blomagtige" en "heuning" aromas, terwyl "vrugtige-soet", "karamel" en "appelkoos" aromas die oorheersende sensoriese eienskappe van die sekondêre profiel is.
Die korrelasie tussen die fenoliese verbindings en die smaak en mondgevoel eienskappe van rooibos ("soet", "suur", "bitter" en "vrankheid") is ondersoek met behulp van verskillende tipe regressieontledings, nl. Pearson se korrelasie, gedeeltelike kleinstekwadrate regressie (PLS) en stapsgewyse regressie. Korrelasies tussen individuele fenoliese verbindings en die smaak en mondgevoel eienskappe was laag, maar steeds betekenisvol. Alhoewel die uitgebreide stel monsters (N = 260) verteenwoordigend was van vyf oesjare (2009-2013) en twee produksiegebiede (Wes-Kaap en Noord-Kaap, Suid-Afrika), kon geen individuele fenoliese verbindings uitgesonder word as betekenisvolle voorspellers van spesifieke smaak of mondgevoel eienskappe nie. Verder is daar ook geen verskil tussen die verskillende produksie-areas wat betref fenoliese samestelling gevind nie. Soortgelyke resultate is bevind vir die sensoriese karakterisering van rooibostee.
Sortering, 'n vinnige sensoriese profileringsmetode, is geëvalueer vir sy potensiële gebruik as 'n gehaltebeheer hulpmiddel vir die rooibosbedryf. Gestrukteerde sortering was suksesvol om rooibos se sensoriese kwaliteit, veral die algemene aroma kwaliteit van rooibos, te bepaal. Hierdie profileringsmetode was egter nie so suksesvol om rooibos se algemene geur, smaak en mondgevoeleienskappe te bepaal nie. Hierdie tendens kan moontlik toegeskryf word aan die betekenisvolle laer intensiteite van laasgenoemde sensoriese eienskappe. Die kategorisering van die rooibos monsters op grond van hul karakteristieke primêre en sekondêre sensoriese profiele is suksesvol deur middel van ongestrukteerde sortering bepaal. In die geheel gesien is die potensiaal van die sorteringstegniek as ‘n vinnige metode om die algemene sensoriese kwaliteit, asook die karakteristieke aroma profiele van rooibos te bepaal, dus bewys. Hierdie vinnige sensoriese profileringstegniek hou dus besliste voordele in vir die rooibosbedryf as dit kom by sensoriese gehaltebeheer.
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Carlsson, Björn. "From achiral to chiral analysis of citalopram." Doctoral thesis, Linköpings universitet, Klinisk farmakologi, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5217.
Full textAbstract:
Within the field of depression the “monoamine hypothesis” has been the leading theory to explain the biological basis of depression. This theory proposes that the biological basis of depression is due to a deficiency in one or more of three key neurotransmitter systems, namely noradrenaline, dopamine and serotonin which are thought to mediate the therapeutic actions of virtually every known antidepressant agent. Citalopram is a selective serotonin-reuptake inhibitor (SSRI) used for the treatment of depression and anxiety disorders. Citalopram is a racemic compound, in other words composed of a 50:50 mixture of two enantiomers (S-(+)-citalopram and R-(-)-citalopram) and with one of the enantiomers (S-(+)-citalopram) accounting for the inhibitory effect. At the time of introduction of citalopram the physician needed a therapeutic drug monitoring service to identify patients with interactions, compliance problems and for handling questions concerning polymorphic enzymes and drug metabolism. An achiral analytical separation method based on solid-phase extraction followed by high-performance liquid chromatography (HPLC) was developed for routine therapeutic drug monitoring (TDM) of citalopram and its two main demethylated metabolites. As the data available on citalopram were from achiral concentration determinations and to be able to further investigate citalopram enantiomers effects and distribution, a chiral method for separation of the enantiomers of citalopram and its demethylated metabolites was established. The advances within chiral separation techniques have made measurement of the concentrations of the individual enantiomers in biological fluids possible. The process behind enantioselective separation is however not fully understood and the mechanism behind the separation can be further scrutinized by the use of multivariate methods. A study of the optimization and characterization of the separation of the enantiomers of citalopram, desmethylcitalopram and didesmethylcitalopram on an acetylated ß-cyclodextrin column, by use of two different chemometric programs - response surface modelling and sequential optimization was performed. Sequential optimization can be a quicker mean of optimizing a chromatographic separation; response surface modelling, in addition to enabling optimization of the chromatographic process, also serves as a tool for learning more about the separation mechanism. Studies of the antidepressant effect and pharmacokinetics of citalopram have been performed in adults, but the effects on children and adolescents have only been studied to a minor extent, despite the increasing use of citalopram in these age groups. A study was initiated to investigate adolescents treated for depression, with respect to the steady-state plasma concentrations of the enantiomers of citalopram and its demethylated metabolites. The ratios between the S- and R-enantiomers of citalopram and didesmethylcitalopram were in agreement with studies involving older patients. The concentrations of the S-(+)- and R-(-) enantiomers of citalopram and desmethylcitalopram were also in agreement with values from earlier studies. The results indicate that the use of oral contraceptives may have some influence on the metabolism of citalopram. This might be because of an interaction of the contraceptive hormones with the polymorphic CYP2C19 enzyme. Even though the SSRIs are considered less toxic compared with older monoamine-active drugs like the tricyclic/tetracyclic antidepressants, the risk of developing serious side effects such as ECG abnormalities and convulsions has been seen for citalopram, when larger doses have been ingested. Furthermore, fatal overdoses have been reported where citalopram alone was the cause of death. Data on the toxicity of each of the enantiomers in humans have not been reported and no data on blood levels of the enantiomers in cases of intoxication have been presented. An investigation was initiated on forensic autopsy cases where citalopram had been found at the routine screening and these cases were further analysed with enantioselective analysis to determine the blood concentrations of the enantiomers of citalopram and metabolites. Furthermore the genotyping regarding the polymorphic enzymes CYP2D6 and CYP2C19 were performed. In 53 autopsy cases, we found increasing S/R ratios with increasing concentrations of citalopram. We found also that high citalopram S/R ratio were associated with high parent drug to metabolite ratio and may be an indicator of recent intake. Only 3.8 % were found to be poor metabolizers regarding CYP2D6 and for CYP2C19 no poor metabolizer was found. Enantioselective analysis of citalopram and its metabolites can provide valuable information about the time that has elapsed between intake and death. Genotyping can be of help in specific cases but the possibility of pharmacokinetic interactions is apparently a far greater problem than genetic enzyme deficiency.<br>On the day of the public defence the status of article IV was: Submitted.
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AMARAL, PRISCILA O. "Caracterização química dos neonicotinóides em águas superficiais via cromatografia liquída de alta eficiência acoplada a espectrometria de massas em tandem (HPLC-MS/MS)." reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27879.
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Submitted by Pedro Silva Filho (pfsilva@ipen.br) on 2017-10-09T19:00:00Z
No. of bitstreams: 0<br>Made available in DSpace on 2017-10-09T19:00:00Z (GMT). No. of bitstreams: 0<br>O presente estudo teve como propósito o desenvolvimento de um método para a determinação e a validação de uma metodologia para a identificação e quantificação de Neonicotinóides em águas superficiais coletadas na região de Bauru, no estado de São Paulo. As técnicas analíticas estudadas para o desenvolvimento deste método foram a cromatografia líquida de alta eficiência acoplada a espectrometria de massas em tandem (HPLC - MS/MS), a cromatografia a gás acoplada a espectrometria de massas (GC/MS) e a cromatografia a gás acoplada ao detector de captura de elétrons (GC/ECD). A classe de pesticidas Neonicotinóides foi escolhida para este trabalho por estar relacionada com um súbito desaparecimento de abelhas em colônias de todo o mundo. Este fenômeno é conhecido como colapso de desordem das colônias (Colony Collapse Disorder CCD) e o mesmo é caracterizado por uma rápida perda na população de abelhas adultas. Os Neonicotinóides utilizados neste estudo foram os compostos Clotianidina, Imidacloprido e Tiametoxam que foram proibidos na sua utilização como pesticidas na Europa pelo regulamento de execução nº 540/2011. As amostras foram concentradas utilizando as técnicas de extração em fase sólida (SPE) e extração líquido líquido (LLE) e injetadas no HPLC MS/MS, GC/MS e GC/ECD. As técnicas de GC/ECD e GC/MS não foram satisfatórias para a determinação na matriz água, pois, o limite de detecção (10 mg L-1), esta acima do valor máximo permitido na legislação da agência de proteção ambiental americana (0,6 μg L-1). A técnica de HPLC MS/MS utilizando o modo de monitoramento de reações múltiplas (MRM) provou se adequada para este estudo por obter limites de quantificação entre 5,89 a 8,06 μg L-1 e uma linearidade entre 0,9963 e 0,9993 para os três compostos.<br>Dissertação (Mestrado em Tecnologia Nuclear)<br>IPEN/D<br>Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Lai, Sin Pin. "Furan measurement in transformer oil by UV-Vis spectroscopy using fuzzy logic approach." Curtin University of Technology, Department of Electrical and Computer Engineering, 2009. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=128452.
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An Ultraviolet to Visible (UV-Vis) spectroscopic analysis based on fuzzy logic approach has been developed for furan content measurement in transformer oil. Following the successful identification and quantification of furan derivatives in transformer oil by ASTM D5837 standard, the new approach is able to approximate the furan content more conveniently and economically. As furan concentration level would determine the absorption intensity in UV-Vis spectral range, the fuzzy logic software model developed would exploit this characteristic to aggregate the furans content level in transformer oil. The UV-Vis spectral response at other ambient temperature is also studied. The proposed technique provides a convenient alternative to conventional method of furan measurement by High Performance Liquid Chromatography (HPLC) or Gas Chromatography Mass Spectrometry (GC/MS) in ASTM D5837 Standard.
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Steele, Valerie J. "Organic residue analysis of Red Lustrous Wheelmade Ware vessels traded across the eastern Mediterranean during the Late Bronze Age." Thesis, University of Bradford, 2008. http://hdl.handle.net/10454/5519.
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Red Lustrous Wheelmade Ware (RLWm ware) transport and storage vessels have been excavated from Late Bronze Age (LBA) sites across the eastern Mediterranean. These distinctive vessels were traded for the valuable commodity they contained so far unidentified. Seventy-three sherds (61 RLWm ware, 12 in local fabrics) and two visible residues were analysed for organic residues using standard lipid extraction techniques. Seven residues from a previous study were re-examined. Gas chromatography-mass spectrometry identified four materials - beeswax, bitumen, fat/oil and resin. Beeswax, found only in vessels from Hittite sites in Turkey, was probably used as a post-firing treatment. Fat/oil, present in some sherds from every site, represents the contents of the vessels and showed many of the characteristics of degraded plant oil. Two examples contained a plant sterol and three yielded ricinoleic acid, a biomarker for castor oil. Gas-chromatography compound-specific isotope ratio mass spectrometry of selected residues excluded dairy products, ruminant animal fats and fish oils as source materials for the fats/oils, while comparison with a small database of modern oils created during this study does not exclude plant oils. Selected samples analysed by high performance liquid chromatography-tandem mass spectrometry did not reveal wine residues. Data on the elemental composition of the fabric collected during another study was re-analysed and compared with data from a further published study, confirming the remarkable consistency of RLWm ware fabric. Volume calculations were also attempted to give an estimate of the capacity of the main vessel forms.
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Dutra, Elizângela Abreu. "Determinação de alfahidroxiácidos por eletroforese capilar e cromatografia líquida de alta eficiência em produtos cosméticos." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-29082017-160028/.
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Nos últimos anos vários produtos cosméticos contendo alfahidroxiácidos (AHAs) têm sido desenvolvidos e estão disponíveis no comércio, causando uma grande revolução em relação ao tratamento da pele fotoenvelhecida. Com o aumento da produção desses produtos, torna-se necessário o desenvolvimento e validação de novas metodologias analíticas para determinar os AHAs contidos em preparações cosméticas, tanto para o controle da qualidade do produto como para a segurança do consumidor. Nesta pesquisa os AHAs tartárico, glicólico, lático e mandélico foram analisados simultaneamente por eletroforese capilar (CE) e cromatografia líquida de alta eficiência (CLAE). Os métodos foram validados avaliando-se os parâmetros de linearidade, limite de quantificação, precisão e exatidão. A separação e determinação quantitativa por CE dos ácidos glicólico, tartárico e lático foram realizadas empregando-se um capilar de sílica fundida com comprimento total de 57 cm e 50 cm de comprimento até o detector, 75 µm d.i.; eletrólito constituído de hidrogenoftalato de potássio 10 mmol.L-1, CTAB 0,5 mmol.L-1, pH 4,1; tensão aplicada de -20 kV com detecção UV indireta a 254 nm; temperatura de 35°C. A separação e determinação quantitativa dos ácidos glicólico, tartárico e lático por CLAE foram realizadas empregando-se coluna Sinergy Hydro RP-18 Phenomenex®, fase móvel constituída de solução fosfato de amônio 15 mmol.L-1, tetrabutilamônio 3 mmol.L-1, pH 2,0, vazão 0,7 mL/min e detecção no UV 220 nm. Para determinação do ácido mandélico por CLAE, foi empregada coluna RP-18 Lichrospher® Merck, fase móvel constituída de solução de fosfato de amônio 15 mmol.L-1 / acetonitrila (80/20, v/v) , pH 2,5, vazão 1,0 mL/min. Os métodos propostos apresentaram boa linearidade com coeficiente de correlação (r) > 0,9999, boa especificidade, repetibilidade aceitável com desvio padrão relativo (RSD) < 1% para determinação nas amostras comerciais e exatidão com percentual de recuperação entre 99 e 101%. Os métodos propostos podem ser aplicados para determinação e quantificação de AHAs contidos em produtos cosméticos em curto espaço de tempo.<br>In recent years many new cosmetic products containing alpha-hydroxy acids (AHAs) have been developed and are commercially available, causing a great revolution to the treatment of the photoaging. With the increase of the production of these products, there is a need of development and validation of analytical methods for quantitative determination of AHAs, both for quality control purposes and to avoid excessive concentrations that could cause consumers undesirable side-effects. In this research, AHAs like tartaric, glycolic, lactic and mandelic acids were analyzed simultaneously using capillary electrophoresis (CE) and high performance liquid chromatography (HPLC). The methods were validated evaluating the parameters of linearity, limit of quantitation, precision and accuracy. The separation and determination for tartaric, glycolic and lactic acids using CE involved an uncoated silica capillary with 75 µm i.d. and total length of 57 cm, 50 cm to the detector, with a solution containing 10 mmol.L-1 potassium phthalate as the background electrolyte and 0.5 mmol.L-1 cetyltrimethylammonium bromide as the electroosmotic flow modifier, pH 4.1, the applied voltage was -20 kV with indirect detection at 254 nm, the operating temperature was 35°C. The separation and determination for tartaric, glycolic and lactic acids using HPLC involved an Sinergy Hydro RP-18 Phenomenex® column, a mobile phase constituted of 15 mmol.L-1 ammonium dihydrogen phosphate and 3 mmol.L-1 tetrabutylammmonium bromide, pH 2.0, a flow-rate of 0.7 mL.min-1 and UV detection at 220 nm. For the determination of the mandelic acid using HPLC involved an LiChrospher® 100 RP-18 Merck column, a mobile phase constituted of 15 mmol.L-1 ammonium dihydrogen phosphate / acetonitrila (80/20, v/v) pH 2.5, a flow-rate of 1.0 mL.min-1 and UV detection at 220 nm. The proposed methods presented good linearity with correlation coefficients more than 0.9999, good specificity, acceptable repeatability, with relative standard deviation (RSD) were less than 1% for commercial samples determination, and recoveries were between 99% and 101 %. The proposed methods can be readily applied to commercially available cosmetic product for quantitative analysis with speed.
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Motlová, Tereza. "Speciační analýza selenu v kvasinkách kultivovaných v médiu s přídavkem selenu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216569.
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The aim of the theses was determination of selenium species in yeast Saccharomyces cerevisiae cultivated in medium with added inorganic form of selenium (Sodium Selenite). Concentrations of Sodium Selenite in cultivation medium were 0,1; 1; 10 and 100 mg.l-1. Cultivation was undertaken in fermenting tub for period of 72 hours. Cultivated yeasts were extracted by use of enzymes and subsequently the species of selenium in particular parts of yeasts were determined. In order to determine selenium species, the method of high-performance liquid chromatography in combination with atomic fluorescent spectrometer and technique of hydride generation was used. Having analysed different fractions of the yeasts Saccharomyces cerevisiae it was ascertained that during cultivation the sorption of selenium occurred in form of Se4+ in cell membranes while in cytoplasm no inorganic forms of selenium were found. Furthermore, it was stated that yeasts Saccharomyces cerevisiae are able to metabolically change inorganic forms of selenium to organic forms (selenomethionine), while these forms are present in cytoplasm and they are likely to be bound to proteinic structures of cell membranes. An increase of concentration of Se4+ in cell membranes could be observed as a result of increasing concentration of Sodium Selenite in cultivation medium. In proteinic structures the concentration of organic selenium forms increased only to concentration 10 mg.l-1 of Sodium Selenite in cultivation medium.
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Edwardson, P. A. D. "High Performance Liquid Chromatography of polynucleotides and proteins." Thesis, London School of Hygiene and Tropical Medicine (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376534.
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Ritchie, Harald John. "Development of new packing materials for high performance liquid chromatography." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/14283.
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Forssén, Patrik. "Adsorption isotherm parameter estimation in nonlinear liquid chromatography /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5971.
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Narine, Raymond. "A novel microcomputer-controlled transport detector for high-performance liquid chromatography." Thesis, King's College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281718.
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Smith, Anita Mohler. "Objective judgement of cheese varieties by multivariate analysis of HPLC profiles." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26535.
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An objective analytical method was developed to characterize the taste profiles of five cheese varieties. Nonvolatile water extracts of Cheddar, Edam, Gouda, Swiss, and Parmesan cheeses were analyzed by high performance liquid chromatography (HPLC) with a reversed phase column. The HPLC operating conditions were determined with Mapping Super-Simplex followed by Centroid Mapping Optimization. A ternary gradient elution system was used with an Adsorbosphere C8 column to resolve a maximum number of components. The optimum solvent volume ratio was 96.8 : 1.2 : 2.0 for trifluoroacetic acid (0.1%), acetonitrile, and methanol, with a flow rate of 1.0 mL/min. Over 50.3 min this ratio was changed to 56.3 : 30.3 : 13.4.
Multivariate statistical analyses including principal component and discriminant analyses were applied to 55 peak areas from 106 cheese chromatograms. Principal component analysis reduced the dimensionality of the "data from 55 to 17 principal components, which are-combinations of the original variables, with a 26% loss of explained sample variation. Discriminant analysis on data from a single HPLC column was able to correctly classify cheeses by variety at a greater than 90% success rate. This grouping rate dropped to 64% when data from all four HPLC columns was combined, implicating large between column variations. A semi-trained sensory panel correctly classified cheeses by variety at a 63% rate. This objective method provides a lasting fingerprint of cheese products.<br>Land and Food Systems, Faculty of<br>Graduate
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Scholtzova, Angela. "Scale up and modelling of HPLC." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368109.
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DONALD, GREGORY THOMAS. "Model Chiral Ionic Liquids for High Performance Liquid Chromatography Stationary Phases." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1214325450.
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Witte, Dirk Theodoor. "High performance liquid chromatography for direct and indirect enantiomeric separations of chiral drugs." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 1992. http://irs.ub.rug.nl/ppn/297969609.
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Sexton, Danessa Leann. "Determination of lactose by reversed-phase high performance liquid chromatography." [Johnson City, Tenn. : East Tennessee State University], 2004. http://etd-submit.etsu.edu/etd/theses/available/etd-0328104-212023/unrestricted/SextonD041504f.pdf.
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Thesis (M.S.)--East Tennessee State University, 2004.<br>Title from electronic submission form. ETSU ETD database URN: etd-0328104-212023. Includes bibliographical references. Also available via Internet at the UMI web site.
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Lowe, Christian T. "Retention characteristics of water-soluable calixarene modified mobile phases in HPLC /." Connect to the full text of the document, 1998. http://www.ohiolink.edu/etd/view.cgi?ysu997550028.
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Benvenutti, Laís. "AVALIAÇÃO DA EXTRAÇÃO DE COMPOSTOS FENÓLICOS DO BAGAÇO DE MAÇÃ COM ETANOL PARA APLICAÇÃO EM SIDRA." Universidade Estadual de Ponta Grossa, 2018. http://tede2.uepg.br/jspui/handle/prefix/2465.
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Previous issue date: 2018-02-02<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>A maçã apresenta alta concentração de compostos fenólicos, distribuídos em
diferentes classes as quais apresentam capacidade antioxidante. Além disso,
conferem efeito positivo na formação do sabor, cor e aroma em bebidas derivadas
da fruta. No entanto, durante o processamento, parte da composição fenólica fica
retida no bagaço, principal subproduto da agroindústria da maçã. Desta forma, este
trabalho teve como objetivo a otimização da extração de compostos fenólicos
presentes no bagaço da maçã utilizando solvente de grau alimentício, visando sua
aplicação em sidras a fim de melhorar as características tecnológicas, nutricionais e
sensoriais do produto final. Nos ensaios de extração foram avaliados os efeitos da
concentração de solvente (etanol), temperatura e razão sólido/líquido sobre o
rendimento e atividade antioxidante dos extratos, utilizando o método de superfície
de resposta (MSR). Além disso, foi estudada a cinética da extração, bem como a
estabilidade do extrato. A análise de regressão linear múltipla acoplada ao MSR
sugeriu que a extração seja efetuada utilizando etanol 60%, a 50 °C, na razão
sólido/líquido de 1:20 (m/v). Por meio de um modelo cinético de primeira ordem
foram avaliados os efeitos do tempo e da temperatura sobre a concentração de
equilíbrio da extração, a qual foi atingida aproximadamente aos 50 minutos,
independente da temperatura, com teores de 1852,77; 1728,35 e 1265,29 mg
CAT/kg para as temperaturas de 50, 35 e 20 °C, respectivamente. A partir desses
resultados, a energia de ativação necessária para que ocorra a transferência do
soluto foi 9,01 kJ/mol. Em geral, os flavonoides apresentaram boa estabilidade
durante período de 90 dias, sendo sugerido armazenamento ou aplicação sob
temperatura de 10 °C em pH de aproximadamente 3,5. O extrato obtido nas
melhores condições foi adicionado ao mosto antes do inóculo de levedura e a
fermentação foi monitorada por meio do estudo cinético. Os mostos e pontos da
fermentação (1, 4, 7, 11 e 15 dias) foram avaliados quanto aos fenóis individuais,
açúcares e etanol em cromatografia líquida de alta eficiência (CLAE). Além disso, foi
avaliada a composição fenólica total, flavonoides totais, flavanóis, flavonóis e
atividade antioxidante, bem como, o teor de acidez total titulável, pH e cor. Os
produtos finais foram analisados sensorialmente quanto à intensidade de cor, acidez,
adstringência e amargor por meio de uma escala estruturada, e quanto à qualidade
do odor em escala hedônica de aceitação. A adição do extrato aumentou cerca 40%
a concentração de flavonoides totais, apresentando glicosídeos de quercetina,
compostos presentes apenas no epicarpo da maçã, os quais foram um dos
compostos relacionados com o aumento da atividade antioxidante na sidra com
adição de extrato. A adição do extrato também resultou em maior intensidade de cor
e percepção do amargor e adstringência. Apesar das alterações na composição
fenólica, a adição do extrato não prejudicou a qualidade do odor do produto final.
Portanto, o extrato fenólico obtido com etanol em condições otimizadas foi capaz de
reincorporar parte dos compostos bioativos retidos no bagaço, aumentando a
capacidade antioxidante e alterando características sensoriais responsáveis pela
aceitabilidade da bebida.<br>Apple has high amounts of phenolic compounds, distributed in different classes
which show antioxidant capacity. In addition, the phenolic compounds contribute to
flavor, color and aroma in apple beverages. However, most of the phenolic
compounds, especially the flavonoids, are retained in the apple pomace, during
processing. In this way, this work aimed to optimize the flavonoids extraction from
apple pomace using food grade solvent, and to apply the extracts in ciders in order to
improve the technological, nutritional and sensorial characteristics of the final product.
In the extraction experiments, the effects of solvent concentration (ethanol),
temperature and solid/liquid ratio on process yield and antioxidant activity of the
extracts were evaluated using response surface methodology (RSM). In addition, the
extraction kinetics as well as the stability of the extract were studied. The multiple
linear regression analysis coupled to RSM suggested that the extraction be
performed using ethanol 60% at 50 °C and with solute-solvent ratio of 1:20 (w/v). The
effects of time and temperature on the equilibrium concentration of the extraction
were evaluated, which was reached at approximately 50 minutes with contents of
1852.77; 1728.35 and 1265.29 mg CAT/kg for the temperatures of 50, 35 and 20 ° C,
respectively. The activation energy required for solute transfer to occur was
determined, 9.01 kJ mol-1. In general, the flavonoids showed good stability during the
period of 90 days, being suggested its storage or application under a temperature of
10 °C and pH about 3.5. The extract obtained under the best conditions was added
to the must prior to addition of the yeast inoculum and the fermentation was
monitored by kinetic study. The musts and ciders (1, 4, 7, 11 and 15 days) were
evaluated as to the individual phenols and sugar and ethanol contents were
quantified in high performance liquid chromatography (HPLC). In addition, the total
phenolic composition, total flavonoids, flavanols, flavonols and antioxidant activity, as
well as total titratable acidity, pH and color were evaluated. The final products were
sensorially analyzed for color intensity, acidity, astringency and bitterness by means
of a structured scale. The odor quality was evaluated in a hedonic scale of
acceptance. The addition of the extract increased about 40% in the total flavonoid
content. Quercetin glycosides, compounds present only in the apple epicarp, were
found, being one of the compounds associated for the increase in antioxidant activity.
The cider with the extract addition showed higher intensity of color and perception of
the bitterness and astringency. Despite the changes in phenolic composition, the
addition of the extract did not affect the odor quality of the final product. Therefore,
the phenolic extract obtained with ethanol under optimized conditions was able to
reincorporate bioactive compounds retained in the pomace, increasing the
antioxidant capacity and changing sensorial characteristics responsible for the
acceptability of the beverage.
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Li, Zhiguo. "High-performance liquid chromatography analysis of fatty acids and mathematical modeling of liquid chromatography." Ohio : Ohio University, 2001. http://www.ohiolink.edu/etd/view.cgi?ohiou1179157379.
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Patel, Hasmukh B. "Reversed-phase high-performance liquid chromatography : some basic studies and application in microbial transformation." Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379158.
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