To see the other types of publications on this topic, follow the link: Absorbance interference study.
Journal articles on the topic 'Absorbance interference study'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Absorbance interference study.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Ding, Tao, Lianbai Gu, and Xiang Liu. "Simultaneous determination of chlorine dioxide and hypochlorous acid in bleaching system." BioResources 6, no. 2 (2011): 1868–79. http://dx.doi.org/10.15376/biores.6.2.1868-1879.
Full textAbstract:
This study has demonstrated a rapid spectroscopic method for the determination of chlorine dioxide and hypochlorous acid concentrations in the pulp bleaching processes. It was found that chlorine dioxide and hypochlorous acid have an isosbestic wavelength of 295 nm. The soluble lignin in such a system is the main interference, but can be corrected by determining the absorbances at 295 nm, 380 nm, and 480 nm. Thus, based on the spectroscopic measurements at 295 nm (the isosbestic point wavelength for chlorine dioxide and hypochlorous acid), 380 nm (absorbance wavelength of chlorine dioxide) and 480 nm (the acid soluble lignin absorbance wavelength), the chlorine dioxide and hypochlorous acid concentrations in the bleaching process can be quantified. However, hypochlorous acid was not detected in the real bleaching effluent for its low content. The present method is simple, rapid, accurate, and has the potential for on-line monitoring of the chlorine dioxide bleaching process.
2
Yudistira, Hadi Teguh, and Kiki Kananda. "The Preliminary Microwave Metamaterial Absorber Based on Ring-Shaped for Stealth Technology." IOP Conference Series: Earth and Environmental Science 1209, no. 1 (2023): 012028. http://dx.doi.org/10.1088/1755-1315/1209/1/012028.
Full textAbstract:
Abstract Controlling electromagnetic waves on the material is needed by several applications such as sensors, stealth technology, and energy harvesting. An artificial material that could control electromagnetic waves is called metamaterial. Meanwhile, a metamaterial absorber can absorb the electromagnetic wave. Two concepts can be used to explain the absorbing phenomena on metamaterial absorber: the matching impedance of the air and the part of the imaginary that is high of the index of refractive collectively or the theory of interference that is destructive. The correlation of matching air impedance with destructive interference theory has been found by Yudistira in his previous works. In this study, the preliminary research of metamaterial absorbers based on ring shape is presented. The 40 mm, 35 mm, 30 mm, and 25 mm ring-shaped widths are applied to this work. We used numerical simulation work to understand the performance of metamaterial absorbers based on ring-shaped. CST microwave studio was used for numerical simulation work. The absorbance peak results for w=20, w=17.5, w=15, and w=12.5 mm are 0.92 at 3.43 GHz, 0.95 at 3.7 GHz, 0.95 at 4.04 GHz and 0.99 at 4.47 GHz, severally. The maximum absorbance is yielded to 0.99 absorbances for 25 mm of the width of the ring-shaped.
3
Monteiro-Silva, Jorge, and Martins. "Optical Sensing of Nitrogen, Phosphorus and Potassium: A Spectrophotometrical Approach Toward Smart Nutrient Deployment." Chemosensors 7, no. 4 (2019): 51. http://dx.doi.org/10.3390/chemosensors7040051.
Full textAbstract:
The feasibility of a compact, modular sensing system able to quantify the presence of nitrogen, phosphorus and potassium (NPK) in nutrient-containing fertilizer water was investigated. Direct UV-Vis spectroscopy combined with optical fibers were employed to design modular compact sensing systems able to record absorption spectra of nutrient solutions resulting from local producer samples. N, P, and K spectral interference was studied by mixtures of commercial fertilizer solutions to simulate real conditions in hydroponic productions. This study demonstrates that the use of bands for the quantification of nitrogen with linear or logarithmic regression models does not produce analytical grade calibrations. Furthermore, multivariate regression models, i.e., Partial Least Squares (PLS), which consider specimens interference, perform poorly for low absorbance nutrients. The high interference present in the spectra has proven to be solved by an innovative self-learning artificial intelligence algorithm that is able to find interference modes among a spectral database to produce consistent predictions. By correctly modeling the existing interferences, analytical grade quantification of N, P, and K has proven feasible. The results of this work open the possibility of real-time NPK monitoring in Micro-Irrigation Systems.
4
Levitt, Stephen R. "Spectrophotometric Measurement of Lithium in Human Saliva Using the Chromogenic Reagent Thorin." Acta Chimica Slovenica 70, no. 3 (2023): 430–39. http://dx.doi.org/10.17344/acsi.2023.8121.
Full textAbstract:
The feasibility of using the chromogenic dye Thorin to spectrophotometrically measure lithium concentration in human saliva was explored. Absorbance wavelength maximum of the Li-Thorin complex was found to be 480 nm. Absorbance at 480 nm was obtained for saliva calibration standards containing 0.00–5.29 mEq/L of lithium. A least-squares fit produced a regression equation y = 0.128x + 1.449, R = 0.997. This was used to predict lithium concentrations in both artificially prepared lithium/saliva test solutions and in hospitalized patients treated with lithium. Results agree well with atomic absorption spectroscopy. Using a reagent blank with an equivalent amount of saliva as the test samples eliminated protein and electrolyte absorbance interference. This study supports the continued exploration of this method as a non-invasive point-of-care testing approach for monitoring saliva lithium in bipolar disorder.
5
Jhanwar, Bharat, Bhupendra Singh, Geetanjali Saini, and Surajpal Verma. "METHOD DEVELOPMENT AND VALIDATION FOR SIMULTANEOUS ESTIMATION OF LEVOSULPIRIDE AND RABEPRAZOLE SODIUM: A NEW ANALYTICAL Q-ABSORBANCE RATIO APPROACH." Asian Journal of Pharmaceutical and Clinical Research 10, no. 16 (2017): 22. http://dx.doi.org/10.22159/ajpcr.2017.v10s4.21331.
Full textAbstract:
Objective: The aim of the study was to develop a precise, accurate, and rapid ultraviolet spectrophotometric method for simultaneous estimation of levosulpiride (LEVO) and rabeprazole sodium (RBS) in the binary mixture and to validate the method as per ICH guidelines.Method: Estimation of LEVO and RBS was performed by Q-absorbance method. Analysis was performed using the ratio of absorbance at two selected wavelengths, one at iso-absorptive point and other is the absorbance maxima of any one of the components. Single scan spectrum and the overlain spectrum conclude that absorbance maxima of LEVO and RBS are 228 and 291.8 nm, respectively, with a coinciding iso-absorptive point at 255 nm. Method uses a ratio of absorbance for assay at 255 and the second wavelength is 291.8 nm, λmax for RBS. It is also applicable at 228 nm, as the second wavelength.Results: Linearity of LEVO and RBS was found to be 25-125 and 4-36 μg/ml, respectively. The accuracy of the LEVO and RBS was found 99.26% and 99.51%, respectively and Sandell’s sensitivity ranged between 0.0238 and 0.594 μg/cm2. Assay of LEVO (75 mg) and RBS (20 mg) in capsule dosage form was found 99.5% and 98.69% w/w, respectively.Conclusions: The developed method for the estimation of LEVO and RBS in binary mixture were found to be simple, accurate, robust, and reproducible. No interference of excipients and the degraded product was found during the estimation. Therefore, the method can be successfully applied for routine quality control analysis.RBS) in the binary mixture and to validate the method as per ICH guidelines.Method: Estimation of LEVO and RBS was performed by Q-absorbance method. Analysis was performed using the ratio of absorbance at two selected wavelengths, one at iso-absorptive point and other is the absorbance maxima of any one of the components. Single scan spectrum and the overlain spectrum conclude that absorbance maxima of LEVO and RBS are 228 and 291.8 nm respectively with a coinciding iso-absorptive point at 255 nm. Method uses ratio of absorbance for assay at 255 and the second wavelength is 291.8 nm, λmax for RBS. It is also applicable at 228 nm, as the second wavelength.Results: Linearity of LEVO and RBS were found to be 25-125and 4-36 μg/ml respectively. Accuracy of the LEVO and RBS was found 99.26 and 99.51% respectively and Sandell’s sensitivity ranged between 0.0238 and 0.594 𝜇g/cm2. Assay of LEVO (75 mg) and RBS (20 mg) in capsule dosage form was found 99.5 and 98.69% w/w respectively.Conclusions: The developed method for the estimation of LEVO and RBS in binary mixture were found to be simple, accurate, robust and reproducible. No interference of excipients and the degraded product were found during the estimation. Therefore the method can be successfully applied for routine quality control analysis.
6
Lawal, Babatunde AS, and Finian K. Odoala. "Interference in drug assay by phytochemicals: An experience with colorimetric assay of amlodipine in physiological fluids." Tropical Journal of Pharmaceutical Research 22, no. 11 (2024): 2327–32. http://dx.doi.org/10.4314/tjpr.v22i11.12.
Full textAbstract:
Purpose: To investigate the potential interactions between methanol extract of Aframomum melegueta seeds (AMSE) and amlodipine (AML).
 Methods: Amlodipine concentrations 2.5, 5.0, 7.5, 10, 12.5 and 15 µg/mL were assayed in vitro with or without AMSE using potassium ferricyanide/FeCl3 (FeCl3/K4(Fe(CN)6)) method. The resulting solution was wavelength-scanned in the range 380 – 950 nm and absorbance read at 393.1, 455.6 and 774.8 nm.
 Results: Aframomum melegueta seeds (AMSE), when present in biological fluids and solutions of AML, interfered significantly with FeCl3/K4(Fe(CN))6. The highest interference occurred at 774.8 nm, and 50 µg/mL AMSE gave as much as 1.5 absolute unit increase in absorbance of 2.5 µg/mL when compared to its absence. Spectral scan of the sample revealed two additional peaks at 393.1 and 455.6 nm with only 0.07 and 0.16 nm unit increases in the presence of AMSE. Concentration–absorbance relationship at these two wavelengths satisfied Beer-Lambert’s law. Beyond 15 µg/mL AML at 774.8 nm, Beer-Lambert’s law was not followed.
 Conclusion: This study highlights the potential interactions between components of the methanol extract of Aframomum melegueta seeds on assay methods of AML. Furthermore, reliable concentration measurements have been made at 393.1 or 455.6 nm. This should be kept in mind when carrying out drug measurements in populations where concurrent use of herbal remedies is highly probable.
7
Pons, Joan Farré, Alba Alumá, Felipe Antoja, Carmen Biosca, María-Jesús Alsina, and Román Galimany. "Evaluation of the Dacos 3.0 analyser." Journal of Automatic Chemistry 12, no. 4 (1990): 153–62. http://dx.doi.org/10.1155/s1463924690000207.
Full textAbstract:
The selective multitest Coulter Dacos 3.0 analyser was evaluated according to the guidelines of the Comisión de Instrumentación de la Sociedad Española de Química Clínica and of the European Committee for Clinical Laboratory Standards.The evaluation was performed in four steps: examination of the analytical units; evaluation of routine working; study of interferences; and assessment of practicability.The evaluation included a photometric study. The inaccuracy is acceptable for 340 nm and 420 nm, and the imprecision at absorbances from 0.05 to 2.00 ranged from 0.06 to 0.28% at 340 nm and from 0.06 to 0.08% at 420 nm. The linearity showed some dispersion at low absorbance for PNP at 420 nm and the drift was negligible.The imprecision of the pipette delivery system, the temperature control system and the washing system were satisfactory.In routine work conditions, seven analytical methods were studied: glucose, creatinine, iron, total protein, AST, ALP and calcium. Within-run imprecision ranged, at low concentrations, from 0.9% (CV) for glucose, to 7.6% (CV) for iron; at medium concentrations, from 0.7% (CV) for total protein to 5.2% (CV) to creatinine; and at high concentrations, it ranged from 0.6% (CV) for glucose to 3.9% (CV) for ALP.Between-run imprecision at low concentrations ranged from 1.4% (CV) for glucose to 15.1% (CV) for iron; at medium concentrations it ranged from 1.2% (CV) for protein to 6.7% (CV) for iron; and at high concentrations the range is from l.2for AST to 5.7% (CV) for iron.No contamination was found in the sample carry-over study. Some contamination was found in the reagent carry-over study (total protein due to iron and calcium reagents). Relative inaccuracy is good for all the constituents assayed. Only LDH (high and low levels) and urate (low level) showed weak and negative interference caused by turbidity, and γ-GT (high level) and amylase, bilirubin and ALP (two levels) showed a negative interference caused by haemolysis.
8
Jiang, Fengcheng, Yao Qiu, Mingshi Wang, et al. "Interference and Elimination of Fe3+ During Spectrophotometric Testing of Typical Pollutants in Coking Wastewater." International Journal of Natural Resources and Environmental Studies 2, no. 2 (2024): 63–69. http://dx.doi.org/10.62051/ijnres.v2n2.07.
Full textAbstract:
As typical pollutants in coking wastewater, pyridine, indole, quinoline, and phenol have the advantages of rapidity and accuracy when determined in aqueous solution using UV spectrophotometry, but the presence of other substances in the water can interfere with the results. In this study, the spectrophotometric detection of pyridine, indole, quinoline, and phenol in coking wastewater was interfered with by Fe3+. To minimize this interference, hydroxylamine hydrochloride (HA) was selected as a masking agent to eliminate the interference of Fe3+ on the detection. The results indicated that spectrophotometric determination was significantly affected by Fe3+, and the level of interference increased with the concentration of Fe3+. HA can effectively reduce the absorbance of Fe3+ in the wavelength range of 250-350 nm. It exhibits a strong masking effect on the determination of Fe3+ in indole and phenol solutions, but it hampers the detection of pyridine and quinoline. HA has a better elimination effect on the interference of different concentrations of Fe3+, which can make the relative error of the determination results of indole and phenol less than 5% and 10%, respectively.
9
Andraos, Charlene, Il Je Yu, and Mary Gulumian. "Interference: A Much-Neglected Aspect in High-Throughput Screening of Nanoparticles." International Journal of Toxicology 39, no. 5 (2020): 397–421. http://dx.doi.org/10.1177/1091581820938335.
Full textAbstract:
Despite several studies addressing nanoparticle (NP) interference with conventional toxicity assay systems, it appears that researchers still rely heavily on these assays, particularly for high-throughput screening (HTS) applications in order to generate “big” data for predictive toxicity approaches. Moreover, researchers often overlook investigating the different types of interference mechanisms as the type is evidently dependent on the type of assay system implemented. The approaches implemented in the literature appear to be not adequate as it often addresses only one type of interference mechanism with the exclusion of others. For example, interference of NPs that have entered cells would require intracellular assessment of their interference with fluorescent dyes, which has so far been neglected. The present study investigated the mechanisms of interference of gold NPs and silver NPs in assay systems implemented in HTS including optical interference as well as adsorption or catalysis. The conventional assays selected cover all optical read-out systems, that is, absorbance (XTT toxicity assay), fluorescence (CytoTox-ONE Homogeneous membrane integrity assay), and luminescence (CellTiter Glo luminescent assay). Furthermore, this study demonstrated NP quenching of fluorescent dyes also used in HTS (2′,7′-dichlorofluorescein, propidium iodide, and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl-benzamidazolocarbocyanin iodide). To conclude, NP interference is, as such, not a novel concept, however, ignoring this aspect in HTS may jeopardize attempts in predictive toxicology. It should be mandatory to report the assessment of all mechanisms of interference within HTS, as well as to confirm results with label-free methodologies to ensure reliable big data generation for predictive toxicology.
10
Saputro, Sulistyo, Ngatidjo Hadipranoto, and Agus Kuncaka. "Study on the Interference of Iron, Aluminium and Silicon on the Atomic Absorption Spectrometric Determination of Mangan in Laterite Mineral." Indonesian Journal of Chemistry 1, no. 2 (2010): 98–104. http://dx.doi.org/10.22146/ijc.21950.
Full textAbstract:
Interference of iron, aluminum and silicon on the determination of mangan in laterite mineral by atomic absorption spectrometry has been investigated. Dissolution of laterite mineral into solution have been carried out by wet method destruction using combination of 7 mL of aquaregia, 7.5 mL of concentrated perchloric acid and 9 mL of fluoride acid 48% In sealed teflon flask heated at temperature of about 110 °C for 3 hours to determine the content of Mn element in laterite mineral directly. Interference of these three metals were carried out by evaluating the differences of Mn absorbance at wavelength 279.50 nm and slit width 0.2 nm between the solutions containing mangan only and those containing the some amount of mangan together with the interfering elements at those concentration range in laterite mineral. The result showed that both iron at concentration of 100 ppm until 500 ppm and aluminum at concentration at 3 ppm until 15 ppm caused significant and non-linear interference on the determination of Mn 2 ppm. Interference of iron was effectively eliminated by releasing action of aluminum. The signal depression reductional decrease due to 234 ppm of silicon on the determination of Mn 2 ppm can be eliminated by adding 2.30 mL of CaCl2 0.2% (m/v) into these solution. The content of Mn in the laterite mineral after and before adding of CaCl2 into solution were 2407.04 ± 59.26 μg g-1 and 2311.76 ± 23.61 μg g-1, respectively. This result was significantly different at confidence level 95% as shown by the value of tcalculated=4.91 that was higher than ttable=4.30.
11
Vetten, Melissa A., and Mary Gulumian. "Interference of Gold Nanoparticles with In vitro Endotoxin Detection Assays." Current Nanoscience 16, no. 2 (2020): 204–13. http://dx.doi.org/10.2174/1573413715666181212120013.
Full textAbstract:
Background: Endotoxin-free engineered nanoparticle suspensions are imperative for their successful applications in the field of nanomedicine as well as in the investigations in their toxicity. Gold nanoparticles are known to interfere with various in vitro assays due to their optical properties and potential for surface reactivity. In vitro endotoxin testing assays are known to be susceptible to interference caused by the sample being tested. Objective: This study aimed to identify a preferred assay for the testing of endotoxin contamination in gold nanoparticle suspensions. Methods: The interference by gold nanoparticles on three assays namely, the commonly used limulus amebocyte lysate chromogenic assay, the limulus amebocyte lysate gel-clot method, and the less common recombinant Factor C (rFC) assay, was tested. Results: Possible interference could be observed with all three assays. The interference with the absorbance- based chromogenic assay could not be overcome by dilution; whilst the qualitative nature of the gel-clot assay excluded the possibility of distinguishing between a false positive result due to enhancement of the sensitivity of the assay, and genuine endotoxin contamination. However, interference with the rFC assay was easily overcome through dilution. Conclusion: The rFC assay is recommended as an option for endotoxin contamination detection in gold nanoparticle suspensions.
12
Xue, Zhehua, and Lei Li. "Rapid and green detection of manganese in electrolytes by ultraviolet-visible spectrometry to control pollutant discharge." PLOS ONE 17, no. 2 (2022): e0264532. http://dx.doi.org/10.1371/journal.pone.0264532.
Full textAbstract:
Controlling the manganese (Mn2+) concentration is important to product quality in the electrolytic manganese industry. Conventional methods for detecting Mn2+ are complex and reagent-consuming, which makes them slow and polluting. It is of great significance to develop a new fast and environmentally friendly method to quantify Mn2+ in electrolyte. The characteristic ultraviolet-visible (UV-vis) absorbance at 401 nm of Mn2+ will vary linearly with the Mn2+ concentration after data correction. Adjusting the pH, calibrating the spectral bandwidth (SBW) and optical path length (OPL), and subtracting the interference from coexisting substances by linear interpolation improve the measuring accuracy. Mn2+ concentration can be determined by direct fast UV-vis absorbance measurement at characteristic peaks without using harmful reagents which facilitates such measurement to be applicated as on-line detection method for electrolytic manganese industry. The method developed in this study will help achieve the goal of improving the detection speed while cutting back on pollutant discharge from concentration analysis process in electrolytic manganese industry.
13
Zang, Yiheng, Jing Chen, Muhammad Awais, et al. "Nitrate Nitrogen Quantification via Ultraviolet Absorbance: A Case Study in Agricultural and Horticultural Regions in Central China." Agriculture 15, no. 11 (2025): 1131. https://doi.org/10.3390/agriculture15111131.
Full textAbstract:
Soil nitrate nitrogen (NO3−-N) is a key indicator of agricultural non-point source pollution. The ultraviolet (UV) dual-wavelength method is widely used for NO3−-N detection, but interference from complex soil organic matter affects its accuracy. This study investigated how organic matter influences NO3−-N detection by optimizing UV dual-wavelength combinations. Density functional theory (DFT) calculations showed slight spectral broadening of fulvic and humic acids in the presence of NO3−-N under UV spectrum. Standard solutions and soil samples were used to compare the detection performance of different wavelength pairs. The findings indicated that the dual-wavelength combination of 235 nm/275 nm is optimal rather than 220 nm/275 nm for measuring soil samples at NO3−-N concentrations exceeding 5 mg·L−1. The 235/275 nm method gave an average calibration coefficient of 1.57. Compared to the national standard and flow analysis methods, the average relative errors were 19.7% and 22.3% (p < 0.001), respectively, indicating its suitability for practical soil applications. These results demonstrate the method’s potential for rapid and accurate NO3−-N detection in real soil samples, supporting its application in environmental monitoring and agricultural management.
14
Ul Haq, Syed Imran, Tribhuvan Singh, Shaik Mohammed Salman, Afifa Namreen, and Anas Rasheed. "Analytical Method Validation of Azadirachtin Extracted From Azadirachta Indica." INTERNATIONAL JOURNAL OF APPLIED PHARMACEUTICAL SCIENCES AND RESEARCH 2, no. 04 (2017): 99–106. http://dx.doi.org/10.21477/ijapsr.v2i04.9552.
Full textAbstract:
A simple UV spectrophotometric method for the determination of Azadirachtin is developed exhibiting maximum absorbance using distilled water at 542nm.The present study is based on the detection of sample drug concentration using dichloro methane as diluent. All the conditions required were optimized. Statistical analysis was carried out and results of which were satisfactory. The optical characteristics such as absorption maxima, regression analysis and correlation coefficient are obtained. Recovery studies were close to 100% that indicate the accuracy and precision of proposed method and the non-interference of the formulation excipients. All the valid parameters are summarized.
15
Sarif, Niroush Konari, T. Jacob Jane, and Prakash Vipin. "Stability Indicating UV Spectrophotometric Method For Linagliptin and Metformin in Pharmaceutical Dosage Form." Pharmaceutical Methods 8, no. 2 (2017): 01–06. https://doi.org/10.5281/zenodo.14855540.
Full textAbstract:
Introduction: Linagliptin and metformin are newly introduced FDA drug combination for the treatment type 2 diabetic patients.This study reveals the development of three methods for the UV spectrophotometric simultaneous estimation of linagliptin and metformin in pharmaceutical dosage and forced degradation studies on four different stress conditions. Methods: Development of method was based upon simultaneous equation,absorbance ratio and absorbances correction method with a simple solvent system of distilled water. Absorption maxima was found to be 230.4nm, 294.4nm for metformin and linogliptin respectively without mutual interference. Isobestic point for both drugs was chosen at 250.4 nm. Stabilty studies were carried out on acid,alkaline,peroxide and thermal stress conditions. Conculsion: Degradation studies reveals that method capability on different stress condition. This method obeyed Beer’s law in the concentration range of 2-14 μg /ml for metformin and 10-40 μg /ml for linogliptin. The results of the analysis has been validated statistically Method proven to be rapid,precise and cost effective for the routine analysis in pharmaceutical dosage form. Forced degradation outcomes can be used for the development of stable formulation and helps in the planning of proper storage requirement.
16
Pantanowitz, Liron, Gary L. Horowitz, Jan N. Upalakalin, and Bruce A. Beckwith. "Artifactual Hyperbilirubinemia Due to Paraprotein Interference." Archives of Pathology & Laboratory Medicine 127, no. 1 (2003): 55–59. http://dx.doi.org/10.5858/2003-127-55-ahdtp.
Full textAbstract:
Abstract Context.—Paraprotein interference in automated chemistry is uncommon. We describe 2 patients with paraproteinemia and elevated total bilirubin levels measured erroneously using the Roche total bilirubin assay. Objectives.—To explain the mechanism of this artifactual hyperbilirubinemia and to determine its frequency in patients with monoclonal or increased immunoglobulins. Materials and Methods.—The assay was performed manually using serum from 2 index patients and from control patients (without M proteins). Total bilirubin was also determined using another manufacturer's assay. A prospective study was then undertaken using serum from 100 consecutive patients with various monoclonal gammopathies and from 13 patients with polyclonal hypergammaglobulinemia and cryoglobulins. For all patients, serum immunoglobulin (Ig) G, IgA, IgM, total and direct bilirubin, creatinine, and a direct spectrophotometric assessment of icterus were measured. Results.—After the addition of assay reagents, a white precipitate formed in the reaction mixtures containing serum from the index patients, but not in other samples. This turbidity, rather than the expected color change to pink, increased the absorbance and falsely elevated the total bilirubin value. Serum from both index patients was anicteric, their direct bilirubin measurements were unaffected, and total bilirubin measured using an alternate assay was normal. Among the 113 patients studied, no additional spurious total bilirubin values were detected. Conclusion.—Paraprotein interference with the Roche automated total bilirubin assay is caused by precipitate formation. This interference is rare and probably idiosyncratic. Spurious hyperbilirubinemia from paraprotein interference may cause clinical confusion. If artifactual elevation of total bilirubin is suspected, the laboratory should examine the specimen for icterus (manually or by spectrophotometry) or measure total bilirubin using a different method.
17
Steger, W. E., S. Machill, K. Herzog, R. Gerhards, I. Jussofie, and H. Schator. "Infrared Spectroscopy of Site-Dependent Inhomogeneities in Conventional Flexible Polyurethane foam." Cellular Polymers 12, no. 1 (1993): 31–45. http://dx.doi.org/10.1177/026248939301200103.
Full textAbstract:
An IR-microscope was used to study the cell membranes of a flexible PU foam prepared with cell dimensions up to 2.5 mm. Along the membrane's long axis IR-spectra up to 25 overlapping spots with diameters of 200 μm were measured. Varying absorbance values of the IR-signals along the membrane axis indicate variations in the membrane thickness. It was possible to correlate the absorbance values of the methyl-signals with absolute thicknesses calculated from the interference patterns observed in some spectra. In general, membranes elongated in the rise direction were thinner in the upper part. This can be explained by the influence of gravitation during the foaming process when the material is still able to flow. The detailed evaluation of the spectra shows varying concentrations of urea and urethane species across the membrane. Manually separated membranes and struts were investigated by the conventional KBr-disc technique. Statistical treatment of the data obtained shows no significant difference between both sample types. Consequently the reaction process in struts and membranes must be very similar.
18
Osakwe, Odilia Nwadiche, and Andre Siegel. "A Novel Standardized Oxygen Radical Absorbance Assay for Evaluating Antioxidant Natural Products." Journal of AOAC INTERNATIONAL 96, no. 6 (2013): 1365–71. http://dx.doi.org/10.5740/jaoacint.12-452.
Full textAbstract:
Abstract Functional and quantitative evaluation of analytes in crude extracts or semipure mixtures has been considered challenging due to variation in generated results. Some of the drawbacks have been linked to the texture, form, and content of the samples. The crude extracts contain multiple components and, in oxygen radical absorbance capacity (ORAC) assays, have exhibited complex reaction kinetics due to interference or matrix effect. The conventional ORAC assay utilized a single dilution factor that brought about a wide CV difference (60–110%) in antioxidant activity for each extract compared to other dilution factors applied. Due to precision errors introduced from these extremely high CV% differences, determination of antioxidant capacity based on a single dilution may introduce discrepant results. A novel standardized ORAC (SORAC) assay for the determination of antioxidant capacity of dietary plant extracts is described in this study. Using the SORAC assay, positive linear correlations (R2 = 0.95–0.99) were obtained for the sample extracts tested when a multiple dilution strategy was applied. Thus, on the strength of our observations, SORAC has been proposed as an effective tool for assessing antioxidant analytes in a biological matrix. This technique could also be modified for use in other bioanalytical platforms concerned with the analyte matrix effect.
19
Szymański, Tomasz, Marcelina Kempa, Michael Giersig, and Jakub Dalibor Rybka. "Carbon Nanotubes Interference with Luminescence-Based Assays." Materials 13, no. 19 (2020): 4270. http://dx.doi.org/10.3390/ma13194270.
Full textAbstract:
Carbon nanotubes (CNTs) are one of the most promising nanomaterials synthesized to date. Thanks to their unique mechanical, electronic, and optical properties, they have found a wide application in electronics in the production of biosensors and nanocomposites. The functionalization of multiwalled carbon nanotubes (MWCNTs) is aimed at making them biocompatible by adding hydrophilic groups on their surface, increasing their solubility and thus rendering them applicable in the regenerative medicine. So far, there is conflicting information about carbon nanotubes in biological systems. This paper investigates the effect of functionalized, oxidized, multiwalled carbon nanotubes (MWCNT-Ox) on the cytotoxicity of normal human articular chondrocytes (NHAC-kn cell line). Since absorbance-based and fluorescence-based assays were shown to interfere with carbon nanotubes, luminescence-based tests were carried out, as they work on a different method of detection and provide advantages over the mentioned ones. Cell viability and reactive oxygen species (ROS) tests were carried out. The cell viability assay showed that with the increasing MWCNTs concentration, the number of viable chondrocytes was significantly decreasing. Exposure to MWCNT-Ox indicated oxidative stress in the lowest investigated concentration with a decreased amount of ROS with higher concentrations. However, control experiments with adenosine triphosphate (ATP) and H2O2—molecules that are detected by the assays—showed that carbon nanotubes interfere directly with measurement, thus rendering the results unreliable. To understand the exact interference mechanisms, further studies must be taken. In conclusion, this study shows that luminescence-based tests yield erroneous results, confirming that in vitro experiments in the literature concerning carbon nanotubes should be analyzed with caution.
20
Venugopal, N. V. S., B. Sumalatha, and Syedabano. "Spectrophotometric Determination of Malathion in Environmental Samples." E-Journal of Chemistry 9, no. 2 (2012): 857–62. http://dx.doi.org/10.1155/2012/390517.
Full textAbstract:
A simple, rapid, sensitive, and precise spectrophotometric method for the determination of Malathion is described. The method is based on the decomposition of Malathion in the presence of alcoholic KOH. Dimethyldithiophosphate produced is made to react with Ammonium meta vanadate in Nitric acid with the formation of blue color. Acid degradation of too slow to be important under environmental reaction conditions. However, alkaline degradation is too fast to be a pathway in environmental condition. The products of alkaline degradation are temperature dependant. The absorbance maximum was observed at 760 nm. The Beers law is obeyed up to 11 ppm. Interference study was carried for other pesticides.
21
Yung-Tse HUNG and Howard H. PAUL, Bukola M. ADESANMI. "Coagulation-Flocculation Treatment for Naphthol Green Band Flour Wastewater." International Journal for Modern Trends in Science and Technology 6, no. 12 (2020): 190–97. http://dx.doi.org/10.46501/ijmtst061237.
Full textAbstract:
The interference of synthetic dye in the water bodies and environment poses a risk to both human and environmental health. Due to the recalcitrant nature of dye and presence of many other pollutants in industrial wastewater, efficient method of treatment of industrial effluent is required to address the lingering problem over the years. To address this major concern, experimental was carried out on synthetic dye and flour wastewater treatment by coagulation-flocculation while varying operating parameters (dosage, concentration, coagulant type etc.). The effectiveness of coagulation-flocculation process for the removal of Naphthol Green B in a mixture of dye wastewater and flour wastewater at different concentrations (50 ppm, 100 ppm, 150 ppm, 200 ppm) was investigated. Using 3 coagulant (FeCl3, FeSO4 and Al2(SO4)3), color removal efficiency was also investigated. The effectiveness of the coagulation process was measured for transmittance and absorbance as indices using UV-Vis Spectrophotometer. Also, the total organic carbon (TOC) was measured. Transmittance and absorbance values of 99.6% and 0.001 respectively were achieved post treatment. Ferric Chloride and Aluminum Sulfate gave better results than Ferrous Sulfate which gave the poorest transmittance and absorbance values indicating reduced color removal efficiency. The results of this study revealed that coagulation process is an efficient preliminary treatment for appreciable suspended particles and color removal from dye wastewater. It also showed the impact of coagulant dosage, dye strength and combined wastewater samples on the removal efficiency and resulting effluent quality.
22
Sangule, Omprakash Tukaram. "Pyridine-2-Carbaldehyde Thiosemicarbazone and its Cobalt(II) Complex: Synthesis, Characterization, and Spectrophotometric Study." International Journal of Research and Innovation in Applied Science X, no. V (2025): 906–15. https://doi.org/10.51584/ijrias.2025.100500080.
Full textAbstract:
This study reports the synthesis, spectroscopic characterization, and analytical application of Pyridine-2-carbaldehyde thiosemicarbazone (Py-2-TSC) and its cobalt(II) complex. The ligand Py-2-TSC was synthesized and characterized using UV-visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD), confirming its structural features and purity. The complexation between Co(II) and Py-2-TSC was optimized at pH 3, where a stable 1:1 metal-to-ligand complex formed, exhibiting maximum absorbance at 510 nm with a molar extinction coefficient of 2.77 × 10³ L mol⁻¹ cm⁻¹. The complex remained stable for up to 24 hours and followed Beer’s law over the Co(II) concentration range of 8.48 × 10⁻⁶ to 8.48 × 10⁻⁵ M. Both Job’s method of continuous variation and the mole ratio method confirmed the 1:1 stoichiometry. The low dissociation constant (7.07 × 10⁻⁸) and high stability constant (1.41 × 10⁷) indicated strong and stable complex formation. Interference studies showed good selectivity, with notable interference only from EDTA and acetate ions. The antimicrobial activity of Py-2-TSC was evaluated against Klebsiella pneumoniae, a gram-negative bacterium, and showed promising inhibitory effects. These findings are consistent with literature reports that highlight thiosemicarbazone ligands as bioactive compounds with potential antimicrobial, antifungal, antitumor, and antitubercular activities. Overall, this study establishes Py-2-TSC as a sensitive and selective ligand for the spectrophotometric determination of cobalt(II), while also demonstrating its potential in medicinal chemistry.
23
Shah, Shrey A., Rahul Gundesha, and Jayesh P. Ruparelia. "A Comparative Study for Detection of Melamine in Solution by Interference Sensing Using Functionalized Silver Nanoparticles." Advanced Science Letters 24, no. 8 (2018): 5849–54. http://dx.doi.org/10.1166/asl.2018.12208.
Full textAbstract:
In this research an attempt has been made for instantaneous sensing of melamine, a potential milk adulterant, at room temperature with the help of bio-functionalized silver nanoparticles. The bio-functionalized nanoparticles were made using leaf extracts of Parthenium hysterophorous and Calotropis procera. Also these methods were compared with the nanoparticles that were functionalized with sulfanillic acid. Colorimetric change was the basis of sensing the melamine using these bio-functionalized silver nanoparticles. Melamine upto a limit of 0.1 ppm was detected by the particles prepared using Parthenium hysterophorous leaf extract at room temperature. UV-visible spectroscopy (200–800 nm range) was used to detect the changes in the absorbance of silver nanoparticles with the addition of melamine in different concentrations. DLS studies were carried out to confirm the presence of nanoparticles and to study their surface morphology during sensing. Comparative study showed that Parthenium hysterophorous (noxious hysterophorous) leaf extract was far better and accurate in detecting melamine and was as accurate as the silver nanoparticles functionalized with sulfanillic acid. This can be attributed to the fact that Parthenium hysterophorous leaf extract contains caffeic acid which worked as a reducing agent and also as the bio functionalized chemical. Thus, this method can be further used as a rapid detection of melamine. In addition, this method can be converted into prototype for detection of melamine in industries.
24
Hung, Sheng-Chun, Chih-Cheng Lu, and Yu-Ting Wu. "An Investigation on Design and Characterization of a Highly Selective LED Optical Sensor for Copper Ions in Aqueous Solutions." Sensors 21, no. 4 (2021): 1099. http://dx.doi.org/10.3390/s21041099.
Full textAbstract:
The optical characteristics of copper ion detection, such as the photometric absorbance of specific wavelengths, exhibit significant intensity change upon incident light into the aqueous solutions with different concentrations of metal ions due to the electron transition in the orbit. In this study, we developed a low-cost, small-size and fast-response photoelectric sensing prototype as an optic sensor for copper (Cu) ions detection by utilizing the principle of optical absorption. We quantified the change of optical absorbance from infra-red (IR) light emitting diodes (LEDs) upon different concentrations of copper ions and the transmitted optical signals were transferred to the corresponding output voltage through a phototransistor and circuit integrated in the photoelectric sensing system. The optic sensor for copper (Cu) ions demonstrated not only excellent specificity with other metal ions such as cadmium (Cd), nickel (Ni), iron (Fe) and chloride (Cl) ions in the same aqueous solution but also satisfactory linearity and reproducibility. The sensitivity of the preliminary sensing system for copper ions was 29 mV/ppm from 0 to 1000 ppm. In addition, significant ion-selective characteristics and anti-interference capability were also observed in the experiments by the proposed approach.
25
Lawag, Ivan Lozada, Elisa S. Nolden, Arthur A. M. Schaper, Lee Yong Lim, and Cornelia Locher. "A Modified Folin-Ciocalteu Assay for the Determination of Total Phenolics Content in Honey." Applied Sciences 13, no. 4 (2023): 2135. http://dx.doi.org/10.3390/app13042135.
Full textAbstract:
The Folin-Ciocalteu assay is a widely used method for measuring the total phenolic content (TPC) in honey, but it can be affected by the presence of reducing sugars in honey, which can lead to interference and an over-estimation of its TPC. To optimize the Folin-Ciocalteu assay for honey analysis, the effect of pH on the assay was investigated. A number of pH scenarios were tested using different concentrations of Na2CO3 (0.00%, 0.75%, 0.94%, and 7.50%) in order to minimize reducing sugar interference and maximize the reaction of phenolics in the assay. The modified TPC method was then validated in accordance with current International Council on Harmonisation (ICH) guidelines. The findings of this study demonstrate that the traditional Folin-Ciocalteu assay (using 7.50% aqueous Na2CO3 solution, pH 10.8) leads to a significant overestimation of the TPC of honey due to the interference of reducing sugars. However, a pH of 7.9, achieved by using a 0.75% aqueous Na2CO3 solution, provides suitable conditions to account for most of the phenolic compounds without interference from reducing sugars. This finding was further confirmed by testing various sugar solutions and artificial honey which yielded TPC values below the established limit of detection and quantification of the assay. However, a slight increase in pH, even by a moderate deviation (pH 8.9), leads to significant discrepancies in absorbance readings, indicating that pH control is crucial for the accurate analysis of TPC in honey.
26
Salem, Hesham. "Analytical Study for the Charge-Transfer Complexes of Pregabalin." E-Journal of Chemistry 6, no. 2 (2009): 332–40. http://dx.doi.org/10.1155/2009/194653.
Full textAbstract:
Studies were carried out, for the first time, to investigate the charge-transfer reactions of Pregabalin (PRE) asn-electron donor with various π-acceptors: 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid,pCA), tetracyanoethylene (TCNE) and 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil). Different colored charge-transfer complexes and radical anions were obtained. Different variables affecting the reactions were studied and optimized. The formations of the colored complexes were utilized in the development of simple, rapid and accurate spectrophotometric methods for the analysis of PRE in pure form as well as in its pharmaceutical preparation. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9995-0.9999) were found between the absorbance and the concentrations of PRE in the range of 8-400 µg mL-1. The limits of assays detection ranged from 0.60 to 8.11 µg mL-1. No interference could be observed from the additives commonly present in the capsules. The methods were successfully applied to the analysis of capsules that contain PRE, with good accuracy and precision; the recovery percentages ranged from 100.19±0.83 to 100.50±0.53. The results were compared favorably with the reported method.
27
Evellyn, Carolina Cangussu Sousa, Ramos do Nascimento Tiago, Flávia Silva Maria, Ferreira Rabelo de Melo Nadja, Lago de Carvalho Anaildes, and Gonçalves da Silva Douglas. "Study of Analytical Method for Measure Phosphorus in Groundwater by UV Spectroscopy Visible." International Journal of Innovative Science and Research Technology 7, no. 10 (2022): 1633–36. https://doi.org/10.5281/zenodo.7316075.
Full textAbstract:
In the present work, a spectrophotometric method was used for the determination of phosphorus in water samples from artesian wells of cities in the southwest of Bahia-Brazil. The method was based on the reaction of ammonium molybdate in acid medium with orthophosphate ions to form a complex, after reduction with ascorbic acid and quantification by spectrophotometry. The maximum wavelength of the complex formed was at 880 nm. The calibration curve showed a linear relationship between phosphorus concentrations and absorbance in the concentration range of 0.04 to 1.0 mg L-1 with a linear correlation coefficient equal to 0.993. The method quantification limit was evaluated at 0.04 mg L-1 . The addition and phosphorus recovery tests showed that there was no matrix interference in the procedure. The RSD value was less than 0.07% and recovery was within the range of 97.2 to 98.8%, indicating good precision and accuracy of the method. The phosphorus concentration in the samples analyzed was between 0.134 ± 0.002 to 1.106 ± 0.053 mg L-1 , exceeding the maximum limit established by CONAMA for freshwater, belonging to Class I.
28
Babazadeh, Saeedeh, Ramanand Bisauriya, Marilena Carbone, et al. "Colorimetric Detection of Chromium(VI) Ions in Water Using Unfolded-Fullerene Carbon Nanoparticles." Sensors 21, no. 19 (2021): 6353. http://dx.doi.org/10.3390/s21196353.
Full textAbstract:
Water pollution caused by hexavalent chromium (Cr(VI)) ions represents a serious hazard for human health due to the high systemic toxicity and carcinogenic nature of this metal species. The optical sensing of Cr(VI) through specifically engineered nanomaterials has recently emerged as a versatile strategy for the application to easy-to-use and cheap monitoring devices. In this study, a one-pot oxidative method was developed for the cage opening of C60 fullerene and the synthesis of stable suspensions of N-doped carbon dots in water–THF solutions (N-CDs-W-THF). The N-CDs-W-THF selectively showed variations of optical absorbance in the presence of Cr(VI) ions in water through the arising of a distinct absorption band peaking at 550 nm, i.e., in the transparency region of pristine material. Absorbance increased linearly, with the ion concentration in the range 1–100 µM, thus enabling visual and ratiometric determination with a limit of detection (LOD) of 300 nM. Selectivity and possible interference effects were tested over the 11 other most common heavy metal ions. The sensing process occurred without the need for any other reactant or treatment at neutral pH and within 1 min after the addition of chromium ions, both in deionized and in real water samples.
29
Kowalenko, C. G. "Evaluation of hot KCl extraction as an index of mineralizable N: Ammonium and ultraviolet absorption measurements." Canadian Journal of Soil Science 86, no. 5 (2006): 911–20. http://dx.doi.org/10.4141/s06-047.
Full textAbstract:
Hot KCl extraction was examined as a possible nitrogen (N) soil test. The focus of this study was the influence of the method for determining N in the extracted solution. The study was conducted on a diverse set of Fraser Valley soils of British Columbia, using aerobic incubation as a reference for potential N mineralization rate. The pattern of nitrate and ammonium accumulation over time differed, possibly reflecting differences in organic matter composition, and affecting the interpretation of the results . Results from anaerobic incubation, a simple, alternative method, differed sufficiently from aerobic incubation to warrant caution in using it to estimate mineralization. The MgO steam distillation method was subject to interference in hot KCl extracts; a flow injection system involving room temperature volatilization and diffusion was proposed as a better alternative. Some soils had significant ammonium present before hot KCl extraction, requiring correction. These adjustments, though increasing laboratory requirements, improved the correlation of hot KCl ammonium with aerobically mineralized N. Simple measurements (steam distillation with strong NaOH and ultraviolet absorbance) of organic N extracted by hot KCl were good alternatives for estimating potential N mineralization. Further examination of extraction conditions and measurement variables are required to optimize these methods. Key words: Mineralized soil N, incubation N, soil N test, MgO-steam-distillable N, sodium-hydroxide-distillable N, flow injection analysis, ultraviolet absorbance
30
Suprapto, Suprapto, and Yatim Lailun Ni'mah. "Direct Cu, Fe, and Ni Ions Multicomponent Analysis Using UV-Vis Spectrophotometric Method." IJCA (Indonesian Journal of Chemical Analysis) 6, no. 2 (2023): 106–15. http://dx.doi.org/10.20885/ijca.vol6.iss2.art2.
Full textAbstract:
This study presents a direct multicomponent analysis method using UV-Vis spectrophotometry to determine Cu(II), Fe(III), and Ni(II) ion content without prior complexation or separation. Single and multivariate regression was used to predict metal ion content, and the resulting model was trained and validated using a dataset of 25 multi-component samples. The mean recoveries for Cu(II), Fe(III), and Ni(II) using linear and ridge regression based only on absorbance at 805 nm were 99.97% and 101.6%, 95.42% and 95.65%, and 99.43% and 99.99%, respectively, for the 20% test data. The mean recoveries for Cu(II), Fe(III), and Ni(II) using linear and ridge regression based only on absorbance at 805 nm were 92.27% and 95.03%, 125.3% and 124.11%, and 104.15% and 105.52%, respectively, for the test solution outside of the training data. These results demonstrate the effectiveness of the multivariate UV-Vis spectrophotometric method for the simultaneous determination of Cu(II) and Ni(II) in multicomponent samples, which meets the analysis standard and can be successfully applied. Finally, the study sheds light on the influence of spectral interference on the accuracy of regression models. It highlights the importance of carefully selecting the wavelengths used as predictors in such models. This can have significant implications for developing and validating analytical methods, particularly in cases where multiple analytes were present in a sample.
31
Patil, Pooja A., Hasumati A. Raj, and Gautam B. Sonara. "Q-ABSORBANCE RATIO SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS DETERMINATION OF ATENOLOL AND IVABRADINE HYDROCHLORIDE IN SYNTHETIC MIXTURE." Pharmaceutical and Biological Evaluations 3, no. 2 (2016): 224–30. https://doi.org/10.5281/zenodo.51066.
Full textAbstract:
Objective: It describes Simultaneous estimation of simple, accurate, precise, robust and economical Q-Absorbance ratio spectrophotometric method for Atenolol and Ivabradine HCl in synthetic mixture. Objective of the study was to deliver information related to Ivabradine HCl and Atenolol combination’s analytical method. Methods: Absorbance ratio method for the ratio of absorbance at two selected wavelengths, one which is an iso-absorbtive point and other being the λ-max of one of the two components. Atenolol and Ivabradine HCl showed an iso-absorbtive point at 286.40 nm in methanol. The second wavelength used was 276 nm which is λ<sub>max</sub> of Atenolol in methanol. So it was economic in nature. The linearity was obtained in the concentration range of 20-100 µg/ml for Atenolol and 2-10 µg/ml for Ivabradine HCl. The concentration of the drugs was determined by using ratio of absorbance at iso-absorbtive point and at the λ<sub>max</sub> of Atenolol. Results: This method is linear for both drugs; in range 2-10 µg/ml for Ivabradine HCl and 20-100 µg/ml for Atenolol found at λ<sub>max</sub> of Atenolol 276nm (R<sup>2</sup> = 0.9990) and at Iso-absorptive point 286.40 nm (R<sup>2</sup>= 0.9998). % recovery for Ivabradine HCl found 100.47% and Atenolol 100.32%. And all validation parameter (Robustness, Ruggedness, Interday, Intraday) show %RSD >2%. And Limit of detection for Ivabradine HCl and Atenolol at λ<sub>1</sub> (maximum wavelength) and λ<sub>2</sub> (Iso-absorptive point) was found 0.309 and 0.181 respectively. % Assay for Ivabradine HCl and Atenolol found to be 100.58% and 100.13% respectively. Conclusions: The method was successfully applied to pharmaceutical synthetic mixture which was considered in approved patent which show no interference. The result of analysis has been validated statistically and by recovery studies. So this method accurate, precise, robust, rugged and economic in nature.
32
Li, Jing, Renjie Li, Yan Liu, et al. "In Situ Measurement of NO, NO2, and H2O in Combustion Gases Based on Near/Mid-Infrared Laser Absorption Spectroscopy." Sensors 22, no. 15 (2022): 5729. http://dx.doi.org/10.3390/s22155729.
Full textAbstract:
In this study, a strategy was developed for in situ, non-intrusive, and quantitative measurement of the oxides of nitrogen (NO and NO2) to describe emission characteristics in gas turbines. The linear calibration-free wavelength modulation spectroscopy (LCF-WMS) approach combined with the temperature profile-fitting strategy was utilized for trace NO and NO2 concentration detection with broad spectral interference from gaseous water (H2O). Transition lines near 1308 nm, 5238 nm, and 6250 nm were selected to investigate the H2O, NO, and NO2 generated from combustion. Experiments were performed under different equivalence ratios in a combustion exhaust tube, which was heated at 450–700 K, with an effective optical length of 1.57 m. Ultra-low NOx emissions were captured by optical measurements under different equivalence ratios. The mole fractions of H2O were in agreement with the theoretical values calculated using Chemkin. Herein, the uncertainty of the TDLAS measurements and the limitation of improving the relative precision are discussed in detail. The proposed strategy proved to be a promising combustion diagnostic technique for the quantitative measurement of low-absorbance trace NO and NO2 with strong H2O interference in real combustion gases.
33
R, Vijayalakshmi, Sundar VD, and Dhanaraju MD. "Chemometric-Assisted UV Method for Quantisation of Perindopril and Losartan in Tablet Dosage Form." Der Pharma Chemica 14, no. 12 (2022): 7. https://doi.org/10.4172/0975-413X.14.12.11-17.
Full textAbstract:
In very recent days multivariate calibration techniques are used to resolve mixtures of double or triple compounds with similar spectral characteristics. In many cases, these multivariate methods for the study of spectral data have many more benefits like simple processing and cheaper analysis. These methods have been very often applied for quantitation of drugs, as HPLC methods are tedious and conventional spectroscopic methods were slow, expensive and complex. The work proposal describes new spectrophotometric methods for the concurrent estimation of Perindopril (PRN) and Losartan (LRN) in their mixtures and dosage form. The stated chemometric methods are multivariate techniques including PCR and PLS. These techniques employ the concentration statistics matrix, produced by using the several combinations containing the two drugs dissolved in methanol. The absorbance input matrix related to the concentration was deduced by studying the absorbance in between 200–350 nm at 1 nm intervals on the zero-order spectra which does not require any extraction steps. The accuracy values, precision, and linearity ranges of the methods have been tested, and analysing the combinations having the studied drugs has then been validated. The results confirmed the suitability of the recommended method for the accurate and highly precise analysis of Perindopril and Losartan in pharmaceutical preparations. These developed methods were applied exactly to the formulation mixture preparations without earlier treatment. Also, no expensive laboratory procedure is required. Moreover, the determined techniques are suitable for study without any of the excipient interference.
34
Darwish, Hany W., Ahmed H. Bakheit, and Ibrahim A. Naguib. "Comparative Study of Novel Ratio Spectra and Isoabsorptive Point Based Spectrophotometric Methods: Application on a Binary Mixture of Ascorbic Acid and Rutin." Journal of Analytical Methods in Chemistry 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/2828647.
Full textAbstract:
This paper presents novel methods for spectrophotometric determination of ascorbic acid (AA) in presence of rutin (RU) (coformulated drug) in their combined pharmaceutical formulation. The seven methods are ratio difference (RD), isoabsorptive_RD (Iso_RD), amplitude summation (A_Sum), isoabsorptive point, first derivative of the ratio spectra (1DD), mean centering (MCN), and ratio subtraction (RS). On the other hand, RU was determined directly by measuring the absorbance at 358 nm in addition to the two novel Iso_RD and A_Sum methods. The work introduced in this paper aims to compare these different methods, showing the advantages for each and making a comparison of analysis results. The calibration curve is linear over the concentration range of 4–50 μg/mL for AA and RU. The results show the high performance of proposed methods for the analysis of the binary mixture. The optimum assay conditions were established and the proposed methods were successfully applied for the assay of the two drugs in laboratory prepared mixtures and combined pharmaceutical tablets with excellent recoveries. No interference was observed from common pharmaceutical additives.
35
Tanner, Risto, Jürgen Arund, Ivo Fridolin, and Merike Luman. "Paracetamol Interference in Uric Acid Levels in Uremic Patients Revealed by Monitoring Spent Dialysate." ISRN Nephrology 2013 (October 3, 2013): 1–4. http://dx.doi.org/10.5402/2013/515292.
Full textAbstract:
The aim of this study was to assess removal dynamics of paracetamol (PAR), as an extraordinary chromophore in spent dialysate, upon the optical monitoring of dialysis of end-stage renal disease patients with inflammation complications. Seven dialysis sessions of different patients were followed to whom PAR was used as a pain reliever or antipyretic. Spent dialysate was sampled hourly and analyzed using HPLC with MS/MS and UV detection. Quantitative calculations were made on the basis of the peak areas on the chromatograms at 280 nm for uric acid (UA) and 254 nm for PAR and its metabolites (PAR-M). Peaks of UA, PAR, PAR-glucuronide, and PAR-sulphate were identified on the basis of specific mass spectra. Removal of PAR was found to be proportional to that of uric acid if intake of the drug by patient occurred half a day before dialysis. But disturbances of the UV-absorbance curves at 280 nm were observed related to rise of UA concentration in spent dialysate when PAR was taken by patients in the course of dialysis. The mechanism of such relation remains unknown. It was concluded that possible benefits and risks of treatment of uremic patients with paracetamol-containing drugs may need to be reassessed.
36
Attia, Khalid A. M., Nasr M. A. El-Abassawi, Ragab A. M. Said, Ahmed El-Olemy, and Sherif Ramzy. "Comparative Study Between Zero-Order Spectra-Processing and Ratio Spectra-Manipulating Methods Applied for the Determination of Isoxsuprine Hydrochloride in the Presence of Its Oxidative Degradation Product." Journal of AOAC INTERNATIONAL 100, no. 6 (2017): 1739–46. http://dx.doi.org/10.5740/jaoacint.16-0296.
Full textAbstract:
Abstract Four accurate, precise, and validated stability-indicating spectrophotometric methods handling either zero-order spectra or ratio spectra have been developed and compared for the analysis of isoxsuprine hydrochloride (ISX) in the presence of its oxidative degradation product. The first two methods processed zero-order spectra, namely graphical absorbance ratio or Q-Analysis and area under the curve, whereas the third and fourth methods manipulated ratio spectra, namely the ratio difference spectrophotometric method and derivative ratio. The proposed methods showed good linearity in the range of 2–23 µg/mL. The methods were tested for specificity using laboratory-prepared mixtures containing the drug and its degradation product. The proposed methods were applied for the determination of ISX in Vascular tablets and the obtained results were acceptable, with small percentage RSD values. The validity of the proposed procedures was further assessed by applying the standard addition technique, which showed no interference from excipients. The obtained results were statistically compared with those obtained by the reported method, showing no significant differences when t- and F-tests were applied.
37
Albakaa, Ali Rasool M., Nehad K. Abed, Dina Saleem M. Ameen, Zainab A. Jabbar, and Amany S. Younis. "Development of a Novel Method for Quantitative Determination of Indomethacin." International Journal of Drug Delivery Technology 10, no. 01 (2020): 46–51. http://dx.doi.org/10.25258/ijddt.10.1.8.
Full textAbstract:
A new green analytical chemistry method using a Ultraviolet–visible (UV-Vis) Spectroscopy is proposed to measure Indomethacin (as cuprous complex); Designate, sophisticated, and proved for determination pure mode of indomethacin, and at dosage forms respective. The present study was prepared quantitatively of the Indomethacin complex, and the molar ratio between the cuprous and indomethacin (1:1) is measured by UV-Vis spectroscopy, the maximum absorbance peak of cuprous complex was measured at (319 nm) in wavelength range (190‐900 nm), at range of the concentration (10–60μg.mL-1) the linear calibration curve was painted and show regression equation (Y = 0.0036X – 0.0054) and correlation Coefficient (R2 = 0.9999). This study was validated and applied to the estimation of indomethacin in tablets from one company in Iraqi markets, when the wavelength and the analysis conditions were determined, no interference was found. It was concluded that the advanced method was accurate, sensitive, precise, and repeatable.
38
Prajapati, Krishna V., Hasumati A. Raj, Vineet C. Jain, and Neelam S. Prajapati. "SIMULTANEOUS DETERMINATION OF MESALAZINE AND RIFAXIMIN IN SYNTHETIC MIXTURE USING SPECTROPHOTOMETRIC TECHNIQUE (SIMULTANEOUS EQUATION METHOD)." Pharmaceutical and Biological Evaluations 3, no. 2 (2016): 199–207. https://doi.org/10.5281/zenodo.51062.
Full textAbstract:
Objective: A simple, accurate and precise spectroscopic method was developed for simultaneous estimation of Mesalazine and Rifaximin in synthetic mixture using Simultaneous Equation Method. Objective of the study was to deliver information related to Mesalazine and Rifaximin combination’s analytical method. Methods: The absorbance was measured at 328 nm for Mesalazine and 292 nm for Rifaximin and calibration curves were plotted as absorbance versus concentration, respectively. The method was found to be linear (r<sup>2</sup>> 0.999) in the range of 10-50 μg/ml for Mesalazine at 328 nm. The linear correlation was obtained (r<sup>2</sup>> 0.999) in the range of 10-50 μg/ml for Rifaximin at 292 nm. Results: The limit of determination (LOD) was 0.215 μg/ml and 0.214μg/ml for Mesalazine and Rifaximin respectively. The limit of quantification (LOQ) was 0.652 μg/ml and 0.648 μg/ml for Mesalazine and Rifaximin<strong> </strong>respectively. The accuracy of this method was evaluated by recovery studies and good recovery results were obtained greater than 99%. The method was successfully applied for simultaneous determination of Mesalazine and Rifaximin in binary mixture. Conclusions: The method was successfully applied to pharmaceutical synthetic mixture which is considered in approved patent which show no interference. The result of analysis has been validated statistically and by recovery studies. So this method accurate, precise, robust, rugged and economic in nature.
39
Vieira, L. A., Marilena Valadares Folgueras, M. Tomiyama, and S. R. Prim. "Rice Husk Ash as a Raw Material to Produce Willemite Pigments." Materials Science Forum 912 (January 2018): 44–49. http://dx.doi.org/10.4028/www.scientific.net/msf.912.44.
Full textAbstract:
This study focuses in the synthesis of ceramic pigments based on the crystal structure of willemite (Zn2SiO4). The willemite obtained from the combination of commercial zinc oxide and rice husk ash is produced in a conventional ceramic process without the use of mineralizer agent and with the addition of cobalt oxide or nickel oxide as the source of chromophore ions. The synthesis temperature used was 1200°C. The characterization of pigments involves the use of X-ray diffraction and scanning electron microscopy. The pigments applied in matte enamel and sintered at 1100°C or 1200°C developed color between blue and beige. The construction of absorbance curves showed the color development behavior of each pigment. The results showed the possibility of obtaining willemite, from rice husk ash and the color development efficiency of the material, besides showing the interference of chromophore ion (Ni and Co) in color development.
40
Khateeb, Mouhammed, Basheer Elias, and Fatema Al Rahal. "Validated Spectrophotometric Method to Assay of B6 and B3 Vitamins in Pharmaceutical Forms Using Potassium Iodide and Potassium Iodate." International Letters of Chemistry, Physics and Astronomy 60 (September 2015): 113–19. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.60.113.
Full textAbstract:
A simple, precise and reliable spectrophotometric method for the determination of pyridoxine hydrochloride (vitB6) and nicotinamide (vitB3) in pure form and pharmaceutical formulations has been described. The method is based on the reaction of studied vitamin with a mixture of potassium iodide and potassium iodate in aqueous medium at (250.5oC) to form yellow colored tri iodide ions (I3-). The reaction is followed spectrophotometrically by measuring the absorbance at 290, 335 and 288, 350 nm for vitB6 and vitB3 respectively. Beer's law was obeyed in the range of 0.5-20.0 μg mL-1 for all procedures. Molar absorptivities were found to be 1.49×104, 1.93×104 and 0.89×104, 1.25×104 L mol-1 cm-1, for determination of vitB6 and vitB3 at 290, 335 and 288, 350 nm respectively. The proposed method has been applied to determine the components in commercial forms with no interference from the excipients. A comparative study between the suggested procedures and the official methods showed no significant difference between the two methods.
41
Khateeb, Mouhammed, Basheer Elias, and Fatema Al Rahal. "Validated Spectrophotometric Method to Assay of B<sub>6</sub> and B<sub>3</sub> Vitamins in Pharmaceutical Forms Using Potassium Iodide and Potassium Iodate." International Letters of Chemistry, Physics and Astronomy 60 (September 30, 2015): 113–19. http://dx.doi.org/10.56431/p-2i9i5w.
Full textAbstract:
A simple, precise and reliable spectrophotometric method for the determination of pyridoxine hydrochloride (vitB6) and nicotinamide (vitB3) in pure form and pharmaceutical formulations has been described. The method is based on the reaction of studied vitamin with a mixture of potassium iodide and potassium iodate in aqueous medium at (250.5oC) to form yellow colored tri iodide ions (I3-). The reaction is followed spectrophotometrically by measuring the absorbance at 290, 335 and 288, 350 nm for vitB6 and vitB3 respectively. Beer's law was obeyed in the range of 0.5-20.0 μg mL-1 for all procedures. Molar absorptivities were found to be 1.49×104, 1.93×104 and 0.89×104, 1.25×104 L mol-1 cm-1, for determination of vitB6 and vitB3 at 290, 335 and 288, 350 nm respectively. The proposed method has been applied to determine the components in commercial forms with no interference from the excipients. A comparative study between the suggested procedures and the official methods showed no significant difference between the two methods.
42
M. Sangeetha, A. Swarna Mahalakshmi, and T. Rama Rao. "A review on analytical method development and validation of Ziprasidone HCL by UV spectroscopy in bulk and marketed formulation." IJPAR JOURNAL 13, no. 4 (2024): 806–11. https://doi.org/10.61096/ijpar.v13.iss4.2024.806-811.
Full textAbstract:
This review article provides a comprehensive overview of the development and validation of a UV-Spectroscopic method for the quantification of Ziprasidone Hydrochloride (HCl) in both bulk and marketed formulations. Ziprasidone HCl, an atypical antipsychotic used in the treatment of schizophrenia and bipolar disorder, requires precise analytical methods for its quantification due to its clinical importance. The study emphasizes the methodological aspects, including the selection of solvents, determination of the maximum absorbance wavelength (λmax), and the preparation of standard solutions. The validation process covers key parameters such as linearity, accuracy, precision, specificity, and sensitivity. The method's specificity is confirmed by the lack of interference from common excipients. This UV spectroscopic method is concluded to be simple, reliable, cost-effective, and suitable for routine quality control analysis of Ziprasidone HCl in pharmaceutical preparations. The article also includes a review of the latest literature on analytical methods for Ziprasidone HCl, highlighting recent advancements and comparisons with other techniques such as HPLC.
43
Yasir, Mehmood, Khalid Mahmood Rana, and Akram Waqas. "Development and validation of UV-spectrophotometric methods for quantitative estimation of Drotaverine HCl injection." Pharmaceutical Methods 8, no. 1 (2017): 01–05. https://doi.org/10.5281/zenodo.14854594.
Full textAbstract:
Introduction: The objective of this study is to develop and validate spectrophotometric method for Drotaverine HCl injection analysis. A very simple, unique, novel, protective, secured, reliable and quick method of spectrophotometric estimation in UV-region has been developed for the assay of Drotaverine HCl injection formulation. Method: Methanol and water were used as diluents for the assay of Drotaverine HCl. Results: However no interference was observed in spectrophotometric determinations. ICH guidelines were followed during selection of parameters and these were then validated statistically using neat chromate grams by RSD and %RSD. The Beer’s law was followed when 8-40 mcg/ml concentration was used. Accuracy, linearity, precision and ruggedness were used for the validation of this method. Recovery studies were used to statistically validate the proposed method. Conclusion: UV spectrophotometer was used to scan the standard solution at wavelength between 200 nm to 400 nm on spectrum mode. Maximum absorbance was found at 242 nm.
44
Darwish, Ibrahim A., Tanveer A. Wani, Nasr Y. Khalil, and Hamdy M. Abdel-Rahman. "High throughput microwell spectrophotometric assay for olmesartan medoxomil in tablets based on its charge-transfer reaction with DDQ." Acta Pharmaceutica 64, no. 1 (2014): 63–75. http://dx.doi.org/10.2478/acph-2014-0008.
Full textAbstract:
Abstract The study describes the development and validation of a new microwell-based spectrophotometric assay for determination of olmesartan medoxomil (OLM) in tablets. The formation of a colored charge-transfer (CT) complex between OLM as an n-electron donor and 2,3-dichloro- -5,6-dicyano-1,4-benzoquinone (DDQ) as a p-electron acceptor was investigated, and employed as the basis for the development of the new assay. The proposed assay was conducted in 96-microwell plates. The absorbance of the colored-CT complex was measured at 460 nm with a microplate reader. Optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, a linear relationship with a good correlation coefficient was found between the absorbance and the concentration of OLM in the range of 2-200 μg per well. The limits of detection and quantitation were 0.53 and 1.61 μg per well, respectively. No interference was observed from the excipients present in OLM tablets or from hydrochlorothiazide and amlodipine besylate that were co-formulated with OLM in some of its formulations. The assay was successfully applied to the analysis of OLM in tablets with good accuracy and precision. The assay described herein has a great practical value in the routine analysis of OLM in quality control laboratories, since it has a high throughput property and consumes low volumes of organic solvent. It thus offers a reduction in the exposure of analysts to the toxic effects of organic solvents, as well as a reduction in the cost of analysis.
45
Abdul Rahim, Mohd Aiman Hakimi, Siti Fatimah Samsurrijal, Amirul Al-Ashraf Abdullah, and Siti Noor Fazliah Mohd Noor. "UV–Vis Spectroscopic Trends of Liquid-exfoliated Graphite/ Graphene Nanoplatelets/Bioactive Glass Mixtures." Journal of Physical Science 34, no. 2 (2023): 1–12. http://dx.doi.org/10.21315/jps2023.34.2.1.
Full textAbstract:
Liquid-phase exfoliation of graphene using a suitable solvent is safe, although the sonication period needs further exploration, which may affect the exfoliation process. This study investigated graphene exfoliation in chloroform through UV–Vis spectroscopy. Graphite powder at different ratios was soaked in chloroform and sonicated at different sonication times from 30 min to 180 min and then subjected to centrifugation at 4,000 rpm for 30 min. The supernatant was collected and analysed using UV–Vis spectroscopy at wavelengths between 220 nm and 800 nm. The UV absorbance intensity showed that the presence of exfoliated graphene peaks is free of interference at 120 min. A comparative study was conducted by using graphene in chloroform as controls and adding bioactive glass (BG) within graphite powder-chloroform emulsions in different concentrations at 120 min. Graphene appearance at the anticipated absorption peak at ~270 nm was observed, and BG addition led to agglomeration, which could provide an idea for a better material formulation strategy in developing films that combined graphene/ BG because of their exceptional properties suitable for diverse potential biomedical application.
46
Kamboj, Anjoo, Pawan Sidana, and Upendra K. Jain. "DEVELOPMENT AND VALIDATION OF UV SPECTROSCOPIC METHODS FOR SIMULTANEOUS ESTIMATION OF SALBUTAMOL SULPHATE AND DOXOPHYLLINE IN COMBINED SOLID DOSAGE FORM." International Journal of Pharmacy and Pharmaceutical Sciences 9, no. 6 (2017): 117. http://dx.doi.org/10.22159/ijpps.2017v9i6.14938.
Full textAbstract:
Objective: Salbutamol sulphate (SBS) and doxophylline (DOX) was used for the treatment of asthma and bronchitis. In the present study, two simple, accurate, precise, reproducible and economical UV-spectroscopic methods (A and B) for simultaneous estimation of SBS and DOX in tablet dosage form have been developed.Methods: In the present study the simultaneous estimation of SBS and DOX was carried out by two methods. Method A employs solving of simultaneous equations based on the measurement of absorbance at two wavelengths, 272 nm and 276 nm which are the 𝜆max values of SBS and DOX respectively in phosphate buffer (pH 7.4). Method B is based on the principle of Q-Analysis where in, absorbance was measured at 225 nm (iso-absorptive point, 𝜆1) and 276 nm (𝜆max of DOX, 𝜆2) in phosphate buffer (pH 7.4).Results: Both SBS and DOX shows linearity at all the selected wavelengths and obeys beer’s law in the concentration range of between 0.2-1.6𝜇g/ml and 0.1-3.5μg/ml at 276 nm; 0.2-1.6 µg/ml and 0.1-4.5 µg/ml at 272 nm and 0.2-2.0µg/ml and 0.2-3.5μg/ml at iso-absorptive point 225 nm. Recovery studies for SBS and DOX were performed and the percentage recovery for both the drugs was obtained in the range of 97.45-98.63% (Method A) and 97.49–98.87 % (Method B) confirming the accuracy of the proposed method.Conclusion: Both the methods showed good reproducibility and recovery with % RSD less than 2. Statistical validation of the data shows that the proposed methods can be successfully applied for the routine analysis of drugs in commercial tablets. Hence, it could be used in the analysis of laboratory samples and marketed formulations containing these two drugs in combined dosage form without the interference of common excipients.
47
Liu, N., A. H. Wu, and S. S. Wong. "Improved quantitative Apt test for detecting fetal hemoglobin in bloody stools of newborns." Clinical Chemistry 39, no. 11 (1993): 2326–29. http://dx.doi.org/10.1093/clinchem/39.11.2326.
Full textAbstract:
Abstract We devised an improved spectrophotometric method, based on the differential susceptibility of various hemoglobins to alkaline denaturation, to measure the percentage of fetal hemoglobin (HbF) in bloody meconium so as to determine the source of the blood. The oxyhemoglobin of a sample was spectrophotometrically scanned from 450 to 650 nm before and after the addition of sodium hydroxide. With Allen baseline correction, the ratio of absorbance at 576 nm was linearly proportional to the percentage of HbF in the specimen as described by the equation: ratio = 0.01 (%HbF) + 0.0045 (r = 0.9971, Sy/x = 0.047). Preliminary studies on samples containing 10% or 80% HbF revealed that the method was fairly precise. The accuracy of this test was verified by comparing the results (y) with those obtained by radial immunodiffusion (x): y = 0.997x + 2.93 (r = 0.91). This preliminary study demonstrates that the modified test is simple, fast, and free from bilirubin interference. It should be useful for the diagnosis of gastrointestinal bleeding of the newborn on a stat basis.
48
Griffin, Brendon. "Cryogenic cooling and in situ analysis of fluid inclusions in geological materials with an ultra-thin windowed Si(Li) detector in a SEM." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (1990): 207. http://dx.doi.org/10.1017/s0424820100134636.
Full textAbstract:
The determination of fluid compositions in geological processes is an essential but difficult problem. Many techniques have been developed based on the optical microscope. These are indirect analytical techniques, determining fluid composition by analogy. More sophisticated spectroscopic techniques, e.g. laser microprobes, are relatively inaccessible through high capital cost. Scanning electron microscopes [SEM’s] and electron microprobes have been used to identify the non-volatile components by decrepitating near-surface inclusions with an energetic electron beam and then analysing the residual.It is found that application of the cryo-SEM to the study of fluid inclusions with the common availability of windowless and low absorbance windowed Si(Li) detectors is a convenient and low cost technique. Suitable slabs (<1 mm) are frozen and then fractured. No coating is applied, to minimise element interference. The fresh surfaces are inspected using backscattered electron [BSE] imaging and exposed inclusions analysed.Studies of inclusions in quartz, fluorite and sphalerite have determined the presence of carbon dioxide, water and various daughter salts, including halite (NaCl) and hydrophilite (CaCl2).
49
Chaganti, Soujanya, Sree Vibha Vangala, Swathi Naraparaju, Pani Kumar Durga Anumolu, and Karuna Devi Barla. "Spectrophotometric Method for Determination of Oseltamivir in Capsule Dosage Form." Scholars Academic Journal of Pharmacy 12, no. 07 (2023): 172–78. http://dx.doi.org/10.36347/sajp.2023.v12i07.002.
Full textAbstract:
Objectives: Study was aimed to establish and vindicate a simple, accurate and precise spectrophotometric method for the quantification of oseltamivir in API and capsule dosage form. Materials and Methods: The green coloured chromogen complex absorbance which was formed by the oxidative coupling with loss of two electrons and a proton of oseltamivir with MBTH in presence of FeCl3 was measured at 640nm. The amount of oseltamivir labelled in the marketed formulation (Fluvir) was determined without any interference owed with excipients. Results: A correlation coefficient of 0.999 was observed within the concentration range of 10-110μg/mL. The method was aided by various validation parameters such as LOD, LOQ and percentage relative standard deviation values (3.75 μg/mL, 9.86 μg/mL and 0.999 respectively). The percentage assay in capsule dosage form was found to be 97.6, which in conformance with ICH guidelines. Conclusion: Results were found to be within the permissible limits. Present method was verified statistically in consonance with ICH Q2R (1) guidelines. Based on above remarks, developed method may be successfully employed in regular analysis of oseltamivir in various pharmaceutical dosage forms.
50
Khan, Jenna, and Wayne Chandler. "Sample Dilution Is Not an Effective Mitigation for Hemolysis Interference in Anti-Xa Heparin Activity Assays." American Journal of Clinical Pathology 152, Supplement_1 (2019): S3—S4. http://dx.doi.org/10.1093/ajcp/aqz112.006.
Full textAbstract:
Abstract The presence of hemolysis or icterus can interfere with chromogenic anti-Xa assays for unfractionated heparin monitoring (heparin activity), resulting in falsely lower estimates of heparin activity. Dilution is a common method for mitigating interference in spectroscopic assays that measure a single analyte by endpoint analysis and has been proposed as a solution for hemolysis interference in heparin activity assays. Heparin activity assays measure heparin/antithrombin complex activity using a chromogenic rate of absorbance change method. Heparin activity is a complex equilibrium of heparin binding to multiple proteins, including antithrombin, heparin cofactor II, platelet factor 4, histidine-rich glycoprotein, vitronectin, fibronectin, and others; some enhance while others neutralize heparin activity. The objective of this study was to determine how dilution affects heparin activity with different starting levels of antithrombin. First samples were diluted without interference (no hemolysis). Samples with 1 U/mL heparin in pooled normal plasma (PNP) and 50% PNP (to simulate 50% antithrombin levels) were diluted 1:1 with PNP versus OK buffer. Dilution resulted in nonlinear changes. Samples with 100% antithrombin recovered 88% of expected activity with PNP versus 74% with OK buffer; samples with 50% antithrombin recovered 111% with PNP versus 77% with OK buffer. Samples were then spiked with varying concentrations of hemolysate and 1:1 dilutions with PNP demonstrated nonlinear recoveries ranging from 41% to 84%. We were unable to recover the original heparin activity with or without hemolysis due to the complex interaction of initial heparin, antithrombin, and other binding protein concentrations with diluent antithrombin and other diluent heparin binding protein levels. When PNP is used as the diluent, the recovery will be lower when the initial antithrombin level is normal due to the addition of other heparin binding proteins; when the initial antithrombin level is low, the recovery is higher due to the addition of antithrombin from the diluent plasma. The recovery is always lower when buffer is used due to dilution of sample antithrombin. Careful consideration should be taken in evaluating the utility of sample dilution to mitigate interference from hemolysis and icterus in heparin activity assays, particularly in patients with fluctuating levels of antithrombin, such as those on extracorporeal life support or with liver failure.