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Littérature scientifique sur le sujet « Chromatographic assays »

Auteur : Grafiati

Publié le 22 novembre 2023

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Articles de revues sur le sujet "Chromatographic assays"

Ristuccia, Patricia A. « Liquid Chromatographic Assays of Antimicrobial Agents ». Journal of Liquid Chromatography 10, n^o 2-3 (février 1987) : 241–76. http://dx.doi.org/10.1080/01483918708066718.

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Reif, Van D., Kevin L. Kaufmann, Nicholas J. Deangelis et Mary C. Frankhouser. « Liquid Chromatographic Assays for Barbiturate Injections ». Journal of Pharmaceutical Sciences 75, n^o 7 (juillet 1986) : 714–16. http://dx.doi.org/10.1002/jps.2600750721.

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Zhao, Qiang, Xing-Fang Li, Yuanhua Shao et X. Chris Le. « Aptamer-Based Affinity Chromatographic Assays for Thrombin ». Analytical Chemistry 80, n^o 19 (octobre 2008) : 7586–93. http://dx.doi.org/10.1021/ac801206s.

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Turpeinen, U., P. Lehtovirta, H. Alfthan et U. H. Stenman. « Interference by human anti-mouse antibodies in CA 125 assay after immunoscintigraphy : anti-idiotypic antibodies not neutralized by mouse IgG but removed by chromatography ». Clinical Chemistry 36, n^o 7 (1 juillet 1990) : 1333–38. http://dx.doi.org/10.1093/clinchem/36.7.1333.

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Abstract Falsely increased concentrations of the ovarian carcinoma-associated antigen, CA 125, were measured by a monoclonal antibody (MAb)-based double determinant immunoradiometric assay (IRMA) in patients who developed antibodies to mouse immunoglobulins (IgGs) after receiving injections of the same MAb as is used in the CA 125 IRMA. Addition of undiluted mouse serum or purified mouse IgG to the assay mixture failed to eliminate the falsely increased CA 125 concentrations in most of the samples, owing to the presence of anti-idiotype antibody. Because of their anti-idiotypic nature, the human anti-mouse antibodies (HAMAS) had only little effect on other immunometric assays, and this effect could be completely eliminated by addition of mouse IgG. To eliminate the effect of HAMA on the CA 125 assay, we studied the ability of various chromatographic methods to separate the interfering HAMA from CA 125. For measuring HAMA in serum and chromatographic fractions we developed a time-resolved fluoroimmunoassay. Adequate separation of CA 125 and HAMA was achieved by affinity chromatography of patients' sera with solid-phase Protein A, Protein G, cation-exchange chromatography on Mono S, and gel filtration on Superose 6. These results demonstrate that the interference can effectively be removed by rather simple chromatographic procedures.

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Williard, Clark V. « Bioanalytical method transfer considerations of chromatographic-based assays ». Bioanalysis 8, n^o 13 (juillet 2016) : 1409–13. http://dx.doi.org/10.4155/bio.16.34.

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Johns, Margaret A., Laura K. Rosengarten, Martha Jackson et Fred E. Regnier. « Enzyme-linked immunosorbent assays in a chromatographic format ». Journal of Chromatography A 743, n^o 1 (août 1996) : 195–206. http://dx.doi.org/10.1016/0021-9673(96)00370-6.

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Londhe, Vaishali, et Madhura Rajadhyaksha. « Review of Recommendations for Bioanalytical Method Validation : Chromatographic Assays and Ligand Binding Assays ». Chromatographia 82, n^o 2 (19 décembre 2018) : 523–35. http://dx.doi.org/10.1007/s10337-018-3677-z.

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Coleman, Mark R., Thomas D. Macy, John W. Morgan et J. Matthew Rodewald. « Ruggedness of the Monensin and Narasin Liquid Chromatographic Assays ». Journal of AOAC INTERNATIONAL 77, n^o 5 (1 septembre 1994) : 1065–72. http://dx.doi.org/10.1093/jaoac/77.5.1065.

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Abstract Supplementary validation data were generated for the monensin and narasin liquid chromatographic (LC) assays. Several parameters of the LC system and the sample preparation procedures were evaluated. Feed samples are routinely extracted in meth-anol-water (9 + 1, v/v). The ratio of methanol to water was varied to evaluate the ruggedness of the extraction procedure. The LC parameters evaluated included flow rates of the mobile phase and vanillin reagent, reactor temperature, and water content of the mobile phase. The resolution of monensin A, monensin B, and narasin A; retention times; tailing factors; peak areas; and peak widths were monitored as LC parameters were varied. The stabilities of monensin and narasin reference standard solutions over time when stored at room temperature and under refrigeration were also monitored. The results show that deviations in the methanol-water ratio of the extraction solution did not significantly affect final assay results. Modification of LC parameters may substantially affect retention time, peak area, and resolution factors.

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Vidal-Casanella, Oscar, Javier Moreno-Merchan, Merce Granados, Oscar Nuñez, Javier Saurina et Sonia Sentellas. « Total Polyphenol Content in Food Samples and Nutraceuticals : Antioxidant Indices versus High Performance Liquid Chromatography ». Antioxidants 11, n^o 2 (7 février 2022) : 324. http://dx.doi.org/10.3390/antiox11020324.

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Total polyphenol content and antioxidant capacity were estimated in various food and nutraceutical samples, including cranberries, raspberries, artichokes, grapevines, green tea, coffee, turmeric, and other medicinal plant extracts. Samples were analyzed by using two antioxidant assays—ferric reducing antioxidant power (FRAP) and Folin–Ciocalteu (FC)—and a reversed-phase high-performance liquid chromatography (HPLC), with a focus on providing compositional fingerprints dealing with polyphenolic compounds. A preliminary data exploration via principal component analysis (PCA) revealed that HPLC fingerprints were suitable chemical descriptors to classify the analyzed samples according to their nature. Moreover, chromatographic data were correlated with antioxidant data using partial least squares (PLS) regression. Regression models have shown good prediction capacities in estimating the antioxidant activity from chromatographic data, with determination coefficients (R2) of 0.971 and 0.983 for FRAP and FC assays, respectively.

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Moraes, Marcela Cristina, Carmen Cardoso, Cláudia Seidl, Ruin Moaddel et Quezia Cass. « Targeting Anti-Cancer Active Compounds : Affinity-Based Chromatographic Assays ». Current Pharmaceutical Design 22, n^o 39 (14 décembre 2016) : 5976–87. http://dx.doi.org/10.2174/1381612822666160614080506.

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Thèses sur le sujet "Chromatographic assays"

Serrano, Nadja Fernanda Gonzaga. « Produção de compostos antimicrobianos por Paenibacillus polymyxa RNC-D : otimização das condições de cultivo, purificação e caracterização dos bioprodutos ». Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/273.

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The increase in the production of antimicrobial metabolites by Paenibacillus polymyxa RNC-D was appraised through the study of cultivation variables. Two process variables, namely the glucose and inoculum concentrations, were evaluated in different levels (5 to 40 g/l, and 2.5% to 5.0% v/v, respectively), and their effects on biomass formation, minimal inhibitory concentration (MIC) against Escherichia coli and surface tension reduction (STR) were studied. The fermentation process was firstly carried out using non-optimized parameters, where the dependent variables biomass, MIC and STR reached the values of 0.6 g/l, 1.000,0 μg/ml and 18.4 mN/m, respectively. The optimum glucose (16 g/l) and inoculum concentrations (5.0% v/v) were defined in order to maximize the biomass formation, with low value of MIC and large STR of extract. Under these conditions, a biomass of 2.76 g/l, MIC of 15.8 μg/ml, and STR of 14.58 mN/m were predicted by the model. Data attained by experiments using optimized settings showed the following values: biomass 2.05 g/l; MIC 31.2 μg/ml; STR 10.7 mN/m. Thus, the percentage of improvement for each target response was: biomass 241.6%; MIC 96.88%; STR 41.85%. It was found that high concentrations of glucose substrate, although reflected in an increase in bacterial biomass, inhibited the microbial secondary metabolism, resulting in a low production of biomolecules associated with high values of MICs. Thus, initial concentrations of glucose and inoculum are shown as variables of strong influence in the production of antimicrobial metabolites by P. polymyxa RNC-D. Through the methods of experimental factorial design and surfaceresponse followed by graphical optimization it was possible to determine the optimum operating condition to achieve both maximum biomass and RTS as well as and lowest possible values of CIM. The validity of the proposed model was verified and confirmed. This is the first study on the optimization of culture conditions for the production of antimicrobial metabolites by P. polymyxa RNC-D, and constitutes an important step in the development of strategies to modulate the production of antimicrobial molecules by this microorganism in elevated levels. Novel antimicrobial compounds were isolated from the fermentation broth of P. polymyxa RNC-D, here named total extract (TE). It was possible to verify the presence of lipopeptide and peptide active compounds through enzymatic assays made with ET. Total extract was subjected to a two-phase system, resulting in lipopeptide extract (LPE) and aqueous fraction (AF). According to the results of bioassays, LPE has broad-spectrum activity against Gram-positive bacteria, Gram-negative bacteria and fungi. The mass spectrometry analysis of PLA revealed the existence of a novel compound that was named polycerradin. The purification of a novel antimicrobial peptide (AMP) from the AF was carried out by using chromatography. The compound was active against Gram-negative bacteria. Nterminal analysis determined the amino acid sequence, as well as MS / MS analysis confirmed the primary structure of this new compound. This research reports firstly the production of PAM PpRNCD that has an unusual amino acid in its constitution. It is an unprecedented fact considering the bacterial specie P. polymyxa. In terms of molecule size, PAM PpRNCD can be considered one of the smallest active natural peptide reported to date. It was also possible to isolate from FA the depsipeptides IL-F04a (m/z 883), LI-F04b (m/z 897), LI-F03a (m/z 947) and LI-F03b (m/z 961) previously described in the literature. The photoluminescence study of the LPE, TE, AF in both at room temperature (RT) and low temperature (T = 8K) was performed. In addition, this technique was applied to evaluate the action of the ELP on Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 29212, Shigella sonnei ATCC 1578 and Candida albicans ATCC 10231 in two different situations: (a) immediately after mixing LPE with the bacterial and fungus cell suspension, and (b) after thirty minutes. The photoluminescence emission was collected by a triple spectrometer (three diffraction gratings) T64000 model from Jobin Yvon, equipped with an optical microscope. For the detection of the radiation emitted by the sample we used a CCD camera (charge coupled device) cooled by liquid nitrogen. The slits of the spectrometer were adjusted to produce a spectral resolution of the order of 10-4 nm. The excitation source used was the line of 457 nm (violet) from an argon laser. The behaviors here observed indicate a strong potential for applications in biosensors as well as molecular markers.
Através do estudo de variáveis do cultivo pretendeu-se aumentar a produção de metabólitos antimicrobianos por Paenibacillus polymyxa RNC-D. Duas variáveis do processo - glicose e concentração de inóculo - foram avaliadas em diferentes níveis e seus efeitos na formação de biomassa, concentração inibitória mínima (CIM) contra Escherichia coli e redução na tensão superficial (RTS) foram estudados. Utilizando parâmetros não-otimizados as variáveis dependentes biomassa, CIM e RTS atingiram valores de 0,6 g/l, 1.000,0 μg/ml e 18,4 mN/m, respectivamente. As concentrações ótimas de glicose (16 g/l) e inóculo (5,0% v/v) foram definidas no sentido de maximizar a formação de biomassa e RTS do extrato, bem como diminuir o valor de CIM do extrato. Experimentalmente 2,05 g/l de biomassa; 31,2 μg/ml de CIM e 10,7 mN/m de RTS foram obtidos sob condições otimizadas. Foi constatado que altas concentrações do substrato glicose, embora refletissem em aumento de biomassa bacteriana, inibiram o metabolismo secundário microbiano, resultando em baixa produção de biomoléculas associada a altos valores de CIM. Através dos métodos de design fatorial experimental e superfície-resposta seguidos por otimização gráfica foi possível determinar a condição operacional ótima das concentrações iniciais de glicose e inóculo, as quais se demonstraram como variáveis de grande influência na produção de metabólitos antimicrobianos por P. polymyxa RNC-D. O extrato total (ET), proveniente do caldo de fermentação de P. polymyxa RNC-D, foi utilizado para pesquisa e isolamento de novos compostos antimicrobianos. Através de ensaios enzimáticos feitos com ET foi possível verificar a natureza lipopeptídica e peptídica dos compostos antimicrobianos. O ET foi submetido a um sistema de duas fases, separandose então em extrato lipopeptídico (ELP) e fração aquosa (FA). Resultados de bioensaios revelaram que o ELP apresenta amplo espectro de atividade contra bactérias Grampositivas, Gram-negativas e fungo. A análise por espectrometria de massas de ELP revelou a presença de um composto peptídico inédito o qual foi denominado polycerradin. A partir da fração aquosa (FA) foi possível a purificação de um novo peptídeo antimicrobiano (PAM) através de etapas cromatográficas. A bioatividade do composto foi avaliada e confirmada frente às bactérias Gram-negativas. A determinação da sequência de aminoácidos foi realizada por análise do N-terminal, e a confirmação da estrutura primária deste novo composto foi feita por MS/MS. O presente estudo relata pela primeira vez a produção do PAM PpRNCD que possui um aminoácido não usual em sua constituição, relato primeiramente aqui descrito considerando-se a espécie bacteriana P. polymyxa. Em termos de tamanho de molécula, pode-se considerar que o PAM PpRNCD é um dos menores peptídeos naturais ativos relatados até o momento. Utilizando-se a FA também foi possível o isolamento dos depsipeptídeos LI-F04a (m/z 883), LI-F04b (m/z 897), LI-F03a (m/z 947) e LI-F03b (m/z 961) previamente descritos na literatura. O estudo da fotoluminescência do ELP, do ET e da FA foi realizado tanto em temperatura ambiente (RT) quanto em baixa temperatura (T=8K). Também se estudou, através desta técnica, a ação do ELP sobre as bactérias Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 29212, Shigella sonnei ATCC 1578 e fungo Candida albicans ATCC 10231 em duas situações: (a) imediatamente após a mistura do ELP com a suspensão celular bacteriana, e (b) trinta minutos após a mistura. Detectou-se emissão fotoluminescente por ELP, ET e FA, e sinais de Raman a λ 699 nm (FA a baixa temperatura). Decorridos 30 min da mistura do ELP com as suspensões celulares microbianas houve alteração na emissão fotoluminescente, sendo que alguns sinais foram suprimidos (λ 470, 480 e 700 nm para S. sonnei, por exemplo). Isto evidencia a potencial aplicação destas frações (ELP, ET e FA) para a fabricação de sensores, detectores e marcadores moleculares.

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Zhang, Qunying. « Characterization of receptors for Escherichia coli 987P using competitive binding assays, thin-layer chromatography and gel filtration chromatography ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0023/MQ51825.pdf.

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Embree, Leanne. « Development of a high-performance liquid chromatographic assay for human chorionic gonadotropin as an alternative to the official United States pharmacopeial animal assay ». Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24637.

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Human chorionic gonadotropin (HCG), a glycoprotein hormone with two nonidentical subunits, is produced by chorionic tissue in pregnant women and by neoplastic tissue containing chorionic elements. It is used in the treatment of male hypogonadism and female sub-fertility. Quantitation of HCG is used to monitor therapy, diagnose various disease states and diagnose and monitor pregnancy. Low levels of HCG in the early and late stages of pregnancy and in various disease states has prompted the development of extremely sensitive assay procedures. Clinically, radioimmunoassay methods are most frequently used due to their precision, sensitivity and cost. However, problems with specificity have been noted. Commercial preparations of HCG must meet the standards outlined in the United States Pharmacopeia (USP). The assay procedure involves a rat uterine weight bioassay. This protocol is lengthy to perform (5 days), requires the sacrifice of a large number of animals (minimum of 60 female rats per assay) and may need to be repeated if the results do not meet the statistical requirements of the assay. Due to the use of animals and the animal care facilities required, this is an expensive assay. In addition, the bioassay is not specific for HCG. Therefore, this thesis reports the analysis of two commercial preparations of HCG, as well as USP Reference Standard HCG and commercially available purified intact HCG and purified individual subunits. Various HPLC assay procedures were evaluated to determine if HPLC would be a viable alternative to the official USP bioassay. Size exclusion HPLC, using one Protein Pak 125 sw column and two Protein Pak 300 sw columns individually and in various combinations, was used to assess all the samples of HCG. Attempts to increase resolution of HCG from interfering components found in these preparations included using both 208 nm and 278 nm for ultraviolet detection, evaluation of 32 buffers as mobile phases with the Protein Pak 300 sw column, fluorescamine derivatization of HCG followed by fluorescence detection, connection of two size exclusion columns in series, and recycling on a Protein Pak 300 sw column. Further attempts to isolate HCG from its protein contaminants involved using ion exchange HPLC with a Protein Pak DEAE 5 pw column with 20 different buffers as mobile phases as well as reversed-phase HPLC with an Ultrasphere ODS column. The greatest resolution was obtained with one Protein Pak 300 sw column with a phosphate buffer (0.15 M, pH 7.0) for the mobile phase and ultraviolet detection. Latex agglutination inhibition slide tests and electrophoresis techniques were used to evaluate commercial samples of HCG and chromatographic peak eluates. Commercial HCG samples appear to contain the individual subunits of HCG and intact HCG along with impurities. The USP Reference Standard HCG contains intact HCG but also contains other ultraviolet absorbing components that were partially separated by HPLC. Electrophoresis also indicated that this HCG sample contained impurities. In addition, the purified intact HCG and purified subunit samples contained impurities, as shown by HPLC. The size exclusion HPLC assay developed using one Protein Pak 300 sw column was unable to resolve intact HCG from the beta-subunit. This assay would be useful for a qualitative assay for purity of HCG preparations. However, at present, HPLC is not a viable alternative to the USP bioassay.
Pharmaceutical Sciences, Faculty of
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Fillmann, Gilberto. « Appraisal and validation of rapid, integrated chemical and biological assays of environmental quality ». Thesis, University of Plymouth, 2001. http://hdl.handle.net/10026.1/2372.

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To assess the significance of pollutants released into the environment it is necessary to determine both the extent of contamination and the biological effects they give rise to. This research is based on a tiered system, which commences with conventional analytical chemistry (gas chromatography), followed by the development, evaluation and application of rapid and simple immunochemical techniques and, finally, the integration of chemical and biological markers to assess pollution. GC-ECD/FID/MS have been used to investigate the status of chemical contamination of the Black Sea by organochlorine residues, hydrocarbons and faecal sterols. Useful information is provided and problems with e.g. HCHs and sewage contamination are highlighted. Contamination by DDTs, PCBs, "total" hydrocarbons and PAHs is also reported. Next, these techniques are used to develop rapid screening methods. Four distinct applications of immunochemical techniques are presented. Initially, the BTEX RaPDD Assay® ELISA is evaluated to detect semi-volatile hydrocarbons in contaminated groundwater. Although overestimating concentrations when compared to GC-FID/PID, results are well correlated. Secondly, the effectiveness o f the BTEX and c-PAH RaPID Assay® to detect hydrocarbons in sediments is tested. Once again, good agreement with GC-FID/MS confirms the ELISA to be a useful screening protocol to focus more expensive high-resolution analytical techniques. The adaptability and applicability of an ELISA (PCB RaPID Assay®) method in measuring "total" PCB levels in mussel tissue is demonstrated. An underestimation of concentrations, despite of covariability between ELISA and cGC-ECD, is discussed. Next, ELISA (RaPID Assay®) and fluorometry were successfully applied to quantify PAH metabolites in crab urine as a measure of exposure. HPLC analyses indicated that conjugate PAH metabolites were dominant in urine of crabs exposed to pyrene. Differences could also be identified between crabs taken from clean and contaminated sites. Finally, an integration of chemical and biological techniques is used to investigate contamination and effects in mussels within a pollution gradient. Results indicate a correlation between micronucleus formation, heart rate and PCB and PAH level.

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Ahmed, Naila Masud. « Chromatographic assay of advanced glycation endproducts and application to the study of human disease ». Thesis, University of Essex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364507.

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Bhattacharjee, Rathindra Chandra. « Development of a sensitive and stereoselective high performance liquid chromatographic assay method for propafenone enantiomers in human plasma ». Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27800.

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Propafenone is a new class 1C antiarrhythmic agent with additional calcium antagonistic and beta-blocking activities. Clinically it is effective in the treatment of supraventricular and ventricular tachycardia, atrial and ventricular fibrillation, ventricular premature contractions and for the management of Wolf-Parkinson-White syndrome. In North America it is still an investigational drug. Propafenone is a chiral drug and is used clinically in the racemic form. The enantiomers of numerous chiral drugs have been shown to differ in their disposition kinetics in the body due to their stereoselective pharmacokinetics and/or pharmacodynamic properties. Two enantiomers are thus often considered as two different entities. The relative antiarrhythmic activities of individual enantiomers of propafenone have not been studied, nor their pharmacokinetic parameters have been elucidated. In order to study the possible enantioselective role of propafenone in the body, a stereoselective assay method would be required. The present study describes the development of a sensitive and stereoselective chromatographic assay method for the simultaneous determination of the two enantiomers of propafenone in human plasma. Attempts for direct separation of the enantiomers of propafenone included several GLC and HPLC chiral stationary phases. The chiral stationary phases were a Chirasil-Valʳ GLC stationary phase, a Pirkle 2,4 dinitro-(D)-phenylglycine HPLC stationary phase and a β-cyclodextrin HPLC stationary phase. Unfortunately, these did not resolve the enantiomers of propafenone. Formation of the diastereomers with R(+)-⍺-methyl benzyl isocyanate and racemic propafenone were partially resolved on a reverse phase HPLC using a 5 u, 25 x 0.45 cm i.d. ODS column and methanol/water (70:30) as the mobile phase. However, due to the long retention time (42 min), incomplete resolution (RS=1.15) and poor sensitivity for detection (500 ng of each enantiomer injected) this method was not deemed suitable for the pharmacokinetic studies planned, since the therapeutic plasma concentration range of propafenone is 64-1044 ng/mL. The second chiral derivatizing reagent, 2,3,4,6-tetra-0-acetyl-β-D-glucopyranosylisothiocyanate (GITC), was synthesized in our laboratory. This reagent gave better resolution of the enantiomers (RS=1.4) within 15 minutes with enhanced sensitivity for detection (150 ng of each enantiomer injected). To further optimize the limit of detection for future pharmacokinetic studies of propafenone, R(-)-1 -(naphthyl) ethylisocyanate, a chiral derivatizing agent, was employed. This reagent reacted with racemic propafenone and permitted the resolution of both enantiomers within 24 minutes (R5=l.25) and the minimum level of detection was 100 ng (at the detector) for each enantiomer of propafenone. Using this method, linearity was established over the concentration range, 125-1000 ng for each enantiomer (injected) with a coefficient of determination (r²) of greater than 0.99. Reproducibility and precision of this assay method was obtained with an average coefficient of variability of 4.5% for the R(-) enantiomer and 7.2% for S(+) enantiomer at concentrations of 125-1000 ng/mL. Below the lower quantity, the NEIC-propafenone reaction virtually stopped at the conditions set for derivatization. A similar lack of reactivity at low concentrations was also observed with the GITC-propafenone reaction. The absence of an autocatalysing effect of propafenone at lower nanogram levels, as well as two possible conformational forms of propafenone were also investigated. The existence of two conformational isomers of propafenone, due to intramolecular hydrogen bonding in aprotic solvents, was chromatographically verified. In addition, chromatographic separation of all the proposed conformers was obtained, indicating that enantiomeric separation and quantitation of propafenone enantiomers as their urea derivatives is substantially hindered. To eliminate hydrogen bonding interactions, the carbonyl group of propafenone was blocked with dansylhydrazine and subsequently derivatized with the chiral R(-)NEIC reagent. The HPLC resolution (RS=1.35) of this dual derivative was better than that using the R(-) NEIC reagent alone, and the minimum level of detection was 2.5 ng for each enantiomer. Unfortunately, this procedure still did not provide adequate assay precision and accuracy at the lower levels required for single dose pharmacokinetic studies.
Pharmaceutical Sciences, Faculty of
Graduate

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CHILAKALA, SUJATHA. « DEVELOPMENT OF LIQUID CHROMATOGRAPHY-MASS SPECTROMETRIC ASSAYS AND SAMPLE PREPARATION METHODS FOR THE BIOLOGICAL SAMPLE ANALYSIS ». Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1512927043412916.

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Lövgren, Ulf. « Enzyme immunoassay in combination with liquid chromatography for sensitive and selective determination of drugs in biosamples ». Lund : Dept. of Analytical Chemistry, Lund University, 1997. http://books.google.com/books?id=Ju1qAAAAMAAJ.

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Kirk, Loren Madden, et Stacy D. Brown. « Beyond-Use Date Determination of Buprenorphine Buccal Solution Using a Stability-Indicating High-Performance Liquid Chromatographic Assay ». Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/5305.

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Objectives The objectives of this study included developing and validating a stability-indicating high-performance liquid chromatographic (HPLC) method with ultraviolet (UV) detection for the determination of buprenorphine in a buccal solution for veterinary use, and applying that method to determine the stability of a 3 mg/ml buprenorphine preparation in room temperature and refrigerated storage conditions. This preparation, intended for buccal administration in feline patients, plays an important role in pain management in cats. Methods A stability-indicating HPLC method was developed and validated for system suitability, accuracy, repeatability, intermediate precision, specificity, linearity and robustness based on US Pharmacopeia (USP) General Chapter. The method was then applied to the study of potency changes over 90 days in a buccal buprenorphine solution stored at two temperatures. Results All HPLC-UV method data met acceptable criteria for the quantification of buprenorphine in a buccal solution formulation. The buprenorphine concentrations found in each stability sample remained within the 90–110% of label claim throughout the 90 days of study. All stability test bottles of the buprenorphine buccal solution retained their original appearance. For the room temperature bottles, some white particulate matter was noted in the threads of the container bottles starting at day 21. The pH of the preparations during the course of the study was in the range of 3.57–4.06 and 4.01–4.16 for the room temperature and refrigerated samples, respectively. Conclusions and Relevance Pharmacists have compounded a concentrated 3 mg/ml buccal solution to use easily in the home care or outpatient setting for treatment of feline pain. Prior to this investigation, pharmacists empirically assigned beyond-use dates to this formulation based on standards in USP General ChapterPharmaceutical Compounding – Nonsterile Preparations. This study of a 3 mg/ml buprenorphine buccal solution indicates stability through 90 days.

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Liu, Tina. « Development and validation of an HPLC assay for simethicone in pharmaceutical formulations ». Master's thesis, Department of Pharmacy, 2001. http://hdl.handle.net/2123/12307.

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Livres sur le sujet "Chromatographic assays"

High performance liquid chromatography in enzymatic analysis : Applications to the assay of enzymatic activity. New York : Wiley, 1987.

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Rossomando, Edward F. High performance liquid chromatography in enzymatic analysis : Applications to the assay of enzymatic activity. New York : Wiley, 1987.

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Chiappetta, Terasa. Comparison of microbiological assay with spectrophotometry and high-performance liquid chromatography in the quantitative analysis of gentamicin spiked in phosphate buffered saline. Sudbury, Ont : Laurentian University, 2004.

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Golubkina, Nadezhda, Elena Kekina, Anna Molchanova et Sergey Nadezhkin. Antioxidants of plants and methods of their definition. ru : INFRA-M Academic Publishing LLC., 2020. http://dx.doi.org/10.12737/1045420.

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The monograph presents the most simple and widely used methods for determining the most important of plant antioxidants: vitamin C, polyphenols, carotenoids, capsaicin, and belinovich photosynthetic pigments, flavonoids, anthocyanins, alkaloids, tannins, and minerals antioxidant: selenium and iodine. Special attention is paid to methods of extraction of antioxidants, providing maximum extraction of antioxidants from plant material, and the correct selection of the most appropriate method of analysis of one or another component. Provides detailed information developed by the authors method of using thin layer chromatography to assess the carotenoid composition of tomatoes and peppers. The data presented here include results of research conducted on the basis of FICO, as well as the latest developments of foreign scientists devoted to natural antioxidants and methods of their determination. Presented in this monograph methodology was successfully tested in the laboratory and analytical Department of PNCO in 2012-2018. For students and teachers and all interested in horticulture and agriculture.

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VandenBoer, Trevor. Development of an analysis for ketamine in wistar rat femoral bone, bone marrow and blood following a single acute administration by enzyme-linked immunosorbent assay and gas chromatography electron capture detection methods. Sudbury, Ont : Laurentian University, 2007.

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German, Igor. Ultrasensitive detection of proteins and peptides by capillary electrophoresis affinity assays. 2001.

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Targove, Margaret Alice. Post-column chemiluminescent detection of pharmaceuticals and direct or indirect electrochemical detection using a carbon paste electrode with high performance liquid chromatography. 1988.

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Puntis, John. Carbohydrate intolerance. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198759928.003.0020.

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Symptoms such as watery diarrhoea, wind, and abdominal cramps should raise the possibility of carbohydrate intolerance. Lactose maldigestion is the most common cause and can be transient, after gastroenteritis, or in some populations is genetically determined with increasing age. Congenital sucrase–isomaltase deficiency (CSID) is underdiagnosed but amenable to treatment with dietary modification and oral enzyme replacement. Glucose–galactose malabsorption presents with watery diarrhoea from the time of first feeds. Investigations include sugar chromatography (when available), breath hydrogen testing, mucosal enzyme assay, and gene testing for CSID.

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Newman, Franklin Scott. Comparison of the Chromatographic and the Microbiological Assay Methods for the Determination of the Nucleic Acids in Newcastle Virus. Creative Media Partners, LLC, 2021.

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Still, Rachel. Evaluation of a high performance liquid chromatography assay for measurement of plasma homocysteine, with application to patients with suspected vitamin B12 or folate deficiency. 1996.

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Chapitres de livres sur le sujet "Chromatographic assays"

Svinarov, D. A. « Unified Liquid Chromatographic and Gas Chromatographic Assays for Therapeutic Drug Monitoring and Toxicology ». Dans Recent Developments in Therapeutic Drug Monitoring and Clinical Toxicology, 691–702. Boca Raton : CRC Press, 2023. http://dx.doi.org/10.1201/9781003418153-107.

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Wainer, Irving W. « Developing Stereoselective High-Performance Liquid Chromatographic Assays for Pharmacokinetic Studies ». Dans ACS Symposium Series, 100–110. Washington, DC : American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0512.ch008.

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Ball, G. F. M. « High-performance liquid chromatographic methods for the determination of thiamin, riboflavin, niacin, vitamin B6 folate and vitamin C ». Dans Water-soluble Vitamin Assays in Human Nutrition, 202–316. Boston, MA : Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2061-0_6.

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Honour, John W. « Gas Chromatography-Mass Spectrometry ». Dans Hormone Assays in Biological Fluids, 53–74. Totowa, NJ : Humana Press, 2006. http://dx.doi.org/10.1385/1-59259-986-9:53.

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Schmidt, Dietmar. « Bioanalytical Assays – Gas Chromatography ». Dans Drug Discovery and Evaluation, 629–42. Berlin, Heidelberg : Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/3-540-29804-5_34.

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Sánchez-Guijo, Alberto, Michaela F. Hartmann et Stefan A. Wudy. « Introduction to Gas Chromatography-Mass Spectrometry ». Dans Hormone Assays in Biological Fluids, 27–44. Totowa, NJ : Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-616-0_3.

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Honour, John W. « High-Performance Liquid Chromatography for Hormone Assay ». Dans Hormone Assays in Biological Fluids, 25–52. Totowa, NJ : Humana Press, 2006. http://dx.doi.org/10.1385/1-59259-986-9:25.

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Schmidt, Dietmar. « Bioanalytical Assays : Gas Chromatography (GC) ». Dans Drug Discovery and Evaluation : Safety and Pharmacokinetic Assays, 835–52. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-25240-2_34.

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Schmidt, Dietmar. « Bioanalytical Assays : Gas Chromatography (GC) ». Dans Drug Discovery and Evaluation : Safety and Pharmacokinetic Assays, 1–19. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-73317-9_34-1.

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Neubert, Hendrik. « Quantification of Protein Biomarkers Using Liquid Chromatography Tandem Mass Spectrometry ». Dans Translating Molecular Biomarkers into Clinical Assays, 87–98. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-40793-7_9.

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Actes de conférences sur le sujet "Chromatographic assays"

Lee, C. H., et A. Lal. « Low-Voltage High-Speed Ultrasonic Chromatography for Microfluidic Assays ». Dans 2002 Solid-State, Actuators, and Microsystems Workshop. San Diego, CA USA : Transducer Research Foundation, Inc., 2002. http://dx.doi.org/10.31438/trf.hh2002.25.

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Zhao, Ming, Dakang Ma, Quanxu Shen et Bin Hong. « Abstract 400 : Immunofluorescence chromatographic assay of tumor cells in dried blood spot ». Dans Proceedings : AACR 107th Annual Meeting 2016 ; April 16-20, 2016 ; New Orleans, LA. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/1538-7445.am2016-400.

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YAMADA, K., T. MEGURO, A. SHIRAHATA, T. NAKAMURA et A. ASAKURA. « EFFECTS OF VITAMIN K ON VITAMIN K DEPENDENT PROTEINS IN NEWBORN INFANTS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644264.

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Plasma levels of vitamin K (VK) and VK dependent proteins ( factor E, factor VH, factor X, protein C and osteocalcin)were determined before and after VK administration to 22 newborn infants. Vitamin K2 syrup ( 2 mg/kg of body weight ) was orally administered to 9 healthy premature, 11 high risk and 2 VK deficient infants under 3 days of age. VK families extracted from plasma were separated by high performance liquid chromatography using a Cosmosil 5 Ci8 column, and separated VK families were detected by a fluorometry after their reaction with ethanolic sodium borohydride in a reaction coil connected by one-line to a chromatographic column. Total activity of factor E, factor VE and factor X was assayed by a Normotest ( Nyegaard ), and protein C was measured by protac/APTT and protac/chromogenic substrate ( S-2366 ) functional assay system ( American Diagnostica ). Osteocalcin levels were assayed by using of a RIA method before and after the absorption of plasma by hydroxyapatite.After VK administration, plasma VK2 ( menaquinone-4 ) content increased from levels less than 0.012yg/ml to levels between 15.9 and 70.9μg/ml, excluding one case in whom plasma VK was not detected after VK administration. Compared with Normotest values and osteocalcin levels of age-matched healthy newborn infants treated without VK, premature, high risk and VK deficient infant levels significantly increased after 24 hrs and after 7 days of VK administration. No correlation was seen between the increase of plasma VK contents and the increase of Normotest values after VK administration. On the other hand, no significant increase of protein C assayed by both methods was observed in healthy premature and high risk infants after VK administration.These results indicate that the change of protein C after VK treatment is different from that of factor II, VII, X and osteocalcin.

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Hori, F., et S. Uno. « Electrochemical Impedance Spectroscopy of Colloidal Gold Nanoparticles in Chromatography Paper for Immunochromatographic Assay ». Dans 2014 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 2014. http://dx.doi.org/10.7567/ssdm.2014.ps-11-14.

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Heiremans, J., M. Claeys et A. G. Herman. « DETERMINATION OF CHOLESTERYL HYDROXYOCTADBCADIENOATES IN VASCULAR TISSUE BY HPLC AND ITS RELEVANCE TO ATHEROSCLEROSIS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643084.

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Accumulation of lipids in the intimal arterial layer, and of cholesterol esters in particular, has been recognised as an early and prominent phenomenon in atherogenesis. Several attempts have been made to link putative peroxidation of these lipids in vivo to causal or deteriorating etiological determinants of plaque formation. The occurrence in advanced human atheromata of oxidized derivatives of cholesteryl linoleate -a major polyunsaturated cholesterol ester species in plasma and vessel wall - has been described by Brooks et al. (Atherosclerosis, 1970,13,223) and a positive correlation between the amount of cholesteryl hydroxyoctadecadienoates (CHODES) and the stage of the lesion has also been reported. In addition Funk and Powell (J. Biol. Chem., 1985,260,7481) have found hydroxyoctadecadienoic acids in normal aorta of different species, wich were strikingly increased after alkaline hydrolysis of total lipids, and this in contrast with the arachidonic acid analogs. The aim of this study was to develop a sensitive and practical method for specific assay of CHODES, without resorting to laborious saponification and derivatisation procedures required for gas chromatographic analysis, which could moreover augment the risk for artefacts.Dog thoracal aorta was homogenised and lipids were extracted using the Folch method with CHCl3/CH30H;2/l containing 0.05mM butylated hydroxytoluene. Fractionation of CHODES from neutral lipids was carried out by thin-layer chromatography. For detection and quantification a high-performance liquid chromatography (HPI/2) assay method was developed, with UV monitoring at 232nm , a wavelength characteristic for conjugated dienes with vicinal hydroxyl function. Reference compounds and the internal standard for HPLC analysis were synthesized from linoleic acid and 10,13,16-docosatrienoic acid, respectively, by preparation of hydroxy fatty acids with soybean lipoxygenase and subsequent esterification to cholesterol esters with pancreas cholesterol esterase. Confirmation of the structural identity was obtained by mass spectrometry. Artefactual formation of CHODES ex vivo was investigated by subjecting radiolabeled cholesteryl linoleate through the analysis procedure. This method allows the specific detection of CHODES in non-atherosclerotic arteries which was hitherto only reported for human advanced atherosclerotic lesions and is proposed as a sensitive and specific probe for prospective survey of lipid peroxidation in atherosclerotic blood vessels.

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Riethorst, W., M. W. P. M. te Booy, T. Beugeling, A. Bantjes, J. Over et W. G. van Aken. « THE ISOLATION OF COAGULATION FACTOR VIII FROM HUMAN BLOOD PLASMA BY AFFINITY CHROMATOGRAPHY ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644059.

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The need for high quality concentrates of coagulation factor VIII (FVIII:C) for treatment of haemophilia A is increasing. As the purity of FVIII:C obtained with existing large scale methods is poor and yields are low, another method for the isolation of FVIII is being developed primarily to avoid losses incurred during cryoprecipitation.Affinity gels were prepared by derivatizing Sepharose CL 4B with different positively charged ligand-spacer combinations. The adsorption of FVIII as well as the von Willebrand factor (VWF) from human blood plasma onto these gels was measured by a one-stage assay for FVIII:C, and enzyme immuno assays (ELISA) for FVIII:CAG and VWF:AG using monoclonal antibodies. The influences of pH, conductivity, ligand density, geltplasma ratio, and length and composition of the spacer as well as the adsorption kinetics were studied to obtain information about the types of interactions responsible for bonding of FVIII to the gels. A combination of at least electrostatic and hydrophobic interactions was concluded to play a role in most cases.At optimal conditions more than 90 % of FVIII could be adsorbed batch-wise from plasma at room temperature in less than one hour with a gel:plasma ratio of 1:20 (i.e. 2.5 g dried gel/1 plasma). In different runs 65-75 % of the FVIII:C applied was recovered by column-wise elution with a salt gradient. The eluate contained less than 0.34 % of the protein applied, which implies that FVIII was purified 190 times. Using fresh-frozen plasma (0.8 IU FVIII/ml) as a starting material for this one-step procedure the final specific activity was 2.3 IU/mg, which is significantly better than that obtained for FVIII isolated by cryoprecipitation. Furthermore, the F. VIII:C to VWF ratio in the eluate was approximately 1:1. The isolated FVIII:C was stable at room temperature and the supernatant plasma appears suitable for further fractionation. It is concluded that this method is worth scaling up and its use for purification of FVIII from other sources is anticipated.

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Tandon, N. N., et G. A. Jamieson. « ROLE OF PLATELET MEMBRANE GLYCOPROTEIN IV IN PLATELET-COLLAGEN INTERACTION : A MICROTITER ASSAY TO STUDY PLATELET ADHERENCE ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643906.

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The role of platelet glycoprotein IV (GPIV) in platelet function has not been elucidated. We have now isolated GPIV (Mr 88,000) from platelet membranes in homogeneous form by a series of steps involving (i) phase partitioning in Triton X-114, (ii) ion exchange chromatography on DEAE-cellulose, (iii) lectin affinity chromatography on WGA-Sepharose, and (iv) size exclusion chromatography on Ultrogel AcA44. Purified GPIV inhibited platelet shape change and aggregation induced by collagen (2 ug/ml; 7 nM as tropocollagen) in a dose-dependent fashion (ID50 ∼ 1 ug/ml; 10 nM) but did not affect aggregation induced by thrombin, ADP, epinephrine, arachidonate or ionophore A23187. To study the role of GPIV in platelet interaction with collagen we have developed a microtiter assay involving (i) coating acid soluble or fibrillar Type I collagen onto microtiter plates, (ii) incubation of coated collagen with 51Cr-labeled platelets and (iii) quantitation of platelet adherence by analysing the radioactivity of the SDS lysate of the adhered platelets. In this assay system, Fab fragments of anti-GPIV antibody inhibited platelet adherence by 75% to both acid soluble and fibrillar Type I collagen while nonimmune serum was without effect. Fab fragments also inhibited collagen-induced aggregation and secretion (ID∼ 10 ug/ml; 200 nM) and, slightly less effectively, aggregation by ADP and epinephrine (ID∼ 300 NM), but did not affect platelet activation by thrombin, arachidonate or ionophore. Fab fragments also inhibited platelet attachment to collagen-Sepharose columns by 80%. These results suggest a role for GPIV in the interaction of platelets with collagen, probably at the level of primary platelet adherence.

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Giddings, J. C. « AN IMMUNORADIOMETRIC ASSAY (IRMA) FOR HUMANTHROMBOMODULIN ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643963.

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Thrombomodulin was separated from detergent-soluble fractions of human placenta using a combination of DEAE-Sepharose and thrombin-Sepharose chromatography. The final product demonstrated one major band (Mr approximately 100000) and three minor bands (Mr 40000 - 80000) on SDS-polyacrylamide gel electrophoresis. The purified protein markedly enhanced the rate of activation of human protein C by thrombin in the presence of calcium ions. Polyclonal antibodies to the isolated thrombomodulin were raised in rabbits and were shown to inhibit thrombin co-factor activity. Immunofluorescence of fibroblasts and of human umbilical vein endothelial cells in culture demonstrated that thrombomodulin antigen was specifically located in endothelial cell membranes. Affinity purified antibody was labelled with 125I and was used to establish an immunoradiometric assay (IRMA). The method was sensitive to approximately 10.0μg purified thrombomodulin per litre. The concentration of thrombomodulin in detergent-solubilised endothelial cells obtained at intervals during primary culture was proportional to the number of cells harvested for assay and appeared to reflect cell growth. Confluent cells from four experiments (approximately 2 × 106 cells per culture dish) contained on average 8.4ng thrombomodulin. Incubation of confluent endothelial cells with medium containing 1 unit per ml human α-thrombin for 10 mins at 37°C reduced the amount of cellular thrombomodulin detected in this assay by up to 30%. Assays of human plasma confirmed that low levels of thrombomodulin are present in normal circulating blood. A mean level of 160μg per litre was detected in 20 normal donors. The levels of thrombomodulin antigen in 10 normal serum were not significantly different from those in the corresponding normal plasma. Preliminary results illustrated that increased levels of thrombomodulin might be found in the plasma of some patients with a variety of clinical disorders. The data suggest that quantitative assays of thrombomodulin might provide a useful index of endothelial disturbances in vivo.

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Lin, Hongxia, Murugesan K. Gounder, Susan Goodin, Joseph R. Bertino, Robert S. DiPaola et Roger K. Strair. « Abstract 2759 : Validated liquid chromatography-mass spectrometry assay for determination of busulfan : Application to clinical pharmacokinetics studies ». Dans Proceedings : AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010 ; Washington, DC. American Association for Cancer Research, 2010. http://dx.doi.org/10.1158/1538-7445.am10-2759.

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GRIFFITH, M., S. A. LIU, G. NESLUND, I. TSANG, D. LETTELIER et R. BERKEBILE. « PREPARATION OF HIGH SPECIFIC ACTIVITY PLASMA AHF BY ANTI-FVIIIc IMMUNOAFFINITY CHROMATOGRAPHY ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643922.

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To reduce the risk of pathogenic virus transmission associated with the therapeutic administration of plasma derived AHF (FVIIIc) we have developed a process wherein anti-FVIIIc immunoaffinity chromatography is used to isolate FVIIIc from a cryoprecipitate solution which has been treated with an organic solvent/detergent mixture to inactivate 1-ipid-enveloped viruses. A final ion exchange chromatography step is used to further remove contaminants (eg. anti-FVIIIc antibody) eluted with FVIIIc during the immunoaffinity step. FVIIIc obtained in the process has a specific activity of 1500 to 2000 AHF units (one stage clotting assay) per mg of protein, representing a ≥120,000-fold purification from plasma. The purified FVIIIc is stabilized for lyophilization and storage by the addition of human albumin. Polyclonal anti-FVIIIc immunoblots reveal polypeptides with apparent mol wts between 90,000 and 230,000 (heavy chain) and 70,000 to 76,000 (light chain). The major လcontaminant” in the preparation is von Willebrand Factor, one mol (Mr = 250,000 subunit) per mol of FVIIIc. Fibrinogen and fibronectin are barely detectable in the final preparation at levels of 1.0 and 0.3 ng per AHF unit respectively, representing a 3 million-fold purification of FVIIIc relative to these proteins. Anti-FVIIIc antibody, used in the immunoaffinity step of the process, is not detectable in the preparation at levels of 2.0 ng/mL (i.e. ≤0.01 ng per AHF unit). The extent to which virus reduction is associated with the process was also evaluated. The addition of an organic solvent/detergent mixture to cryoprecipitate solution resulted in HIV (and other lipid-enveloped viruses) inactivation to levels below the level of assay sensitivity in <5 min; representing a measurable 4 to 5 log reduction in virus titer. In addition, substantial (nonenveloped and lipid-enveloped) virus reduction was associated with the immunoaffinity step used in the process (3,400 to 50,000-fold depending on the virus/experimental conditions studie). The overall process results in a high specific activity AHF preparation which also appears to be substantially improved over previous AHF preparations with respect to viral contamination.

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Rapports d'organisations sur le sujet "Chromatographic assays"

Olsen et Wise. PR-179-12603-R02 Energy Meter Performance Assessment Phase 1 Amendment - Unblinded. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), avril 2014. http://dx.doi.org/10.55274/r0010833.

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Many pipelines utilize system chromatographs at delivery locations. The energy content of the gas delivered can have a significant time skew from the chromatograph. Therefore, the energy content of the gas at a delivery point may differ significantly from its associated system chromatograph. On lean burn engines with tight emission controls, changes in the energy content of the fuel gas can significantly alter the amount of air required to maintain emissions compliance. A reliable, low cost, and fast responding energy meter is desired for both scenarios described. Four Energy Meters are evaluated with six different gas compositions representative of gas compositions encountered on natural gas pipelines. The Energy Meter data is compared to a Micro GC to assess accuracy. After evaluation of the Energy Meters the same six gas compositions were operated in a CFR engine to measure methane number. The measured methane numbers are compared with methane numbers computed from energy meter data.

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Olsen et Wise. PR-179-12603-R03 Energy Meter Performance Assessment Phase 1 Amendment - Blinded. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), juin 2014. http://dx.doi.org/10.55274/r0010559.

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Bora. PR-004-14604-R01 Miniaturized Gas Chromatography and Gas Quality Sensor. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), juin 2015. http://dx.doi.org/10.55274/r0010869.

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The natural gas industry currently relies on gas chromatography to evaluate the composition of natural gas including alkanes, carbon dioxide, nitrogen, and oxygen. The higher and lower heating values, Wobbe Index, Hydrocarbon Dewpoint, Methane Number, and viscosity are all calculated from the gas composition. The need to understand the composition of fuel gas and to monitor its components is crucial to the natural gas industry. Monitoring the composition of the fuel gas provides the industry with the capability of protecting valuable underground assets, delivering gas that meets end-usage requirements, and tracking of constituents for both billing purposes and to ensure compliance with tariff agreements. As with any technology, there are limitations to gas chromatography. Limitations can include high cost, time delay, inability to sample at high pressure, and selectiveness of gas chromatography detectors. This project consisted of a technology assessment of currently available and emerging technologies including micro gas chromatographs, optical spectrometers, and mass spectrometers for their ability to determine gas composition compared to current GC technology. Technologies were investigated and assessed by their analytical characteristics (what components they could analyze and detection limits), their sampling characteristics (sampling pressure limits, scan time, and emissions), and their operational characteristics (availability, cost, consumables, maintenance, and packaging). Recommendations for further testing were made on the technologies whose characteristics showed the most promise for analysis of natural gas at custody transfer points.

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Peterson, Warren. PR-663-19600-Z01 Develop Guidance for Calculation of HCDP in Pipelines. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), mars 2020. http://dx.doi.org/10.55274/r0011659.

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To maintain the integrity and reliability of natural gas transportation systems, system operators ensure that products in transit remain in the gas phase under foreseeable operating conditions. Compliance with pipeline hydrocarbon dew point (HCDP) specifications are demonstrated though in-situ testing or predictive models based on Equations of State (EOS) calculations. Numerical prediction of HCDP is a product of contributing elements, including gas chromatography, calibration gas quality, thermophysical science and the experimental data that underpins equations of state. Some hydrocarbon mixtures, such as those from non-traditional gas supplies, are more difficult to sample and assess than others. The methods described in this paper and accompanying spreadsheet examples are designed to assist persons in making technically defendable decisions with respect to predictive methods and the operational impacts of liquid dropout. The primary focus of this work is to connect the over-all performance of HCDP prediction to its operational implications. The secondary objective of the work is to provide tools for assessing the potential benefit from using C9+ versus C6+ gas chromatographs.

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Moores, Lee C., P. U. Ashvin, I. Fernando et Garret W. George. Synthesis of 2-Methoxypropyl Benzene for Epitope Imprinting. U.S. Army Engineer Research and Development Center, juillet 2022. http://dx.doi.org/10.21079/11681/44883.

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Harmful algal blooms (HABs) are occurring with increasing frequency and severity across the globe in part due to climate change and anthropogenic pollution (Bullerjahn et al. 2016). HABs produce several classes of toxins; however, microcystins (MCs) are the most commonly studied (Lone et al. 2015) and can be potent toxins with LD50s in the range of 50 μg/kg (Puddick et al. 2014). Sample analysis in laboratories, typically by high-pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) or by Enzyme Linked Immunosorbent Assays (ELISAs) (USEPA 2015). These analytical techniques are highly sensitive and selective for the given toxins; however, the time it takes to collect, transfer, prepare, and analyze a sample before the data can be reported is significant; often, multiple days is the most expeditious.

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Annunziato, Dominick. HPLC Sample Prep and Extraction SOP v1.3 for Fungi. MagicMyco, août 2023. http://dx.doi.org/10.61073/sopv1.3.08.11.2023.

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medicine, industry, and biotechnology. Fungi produce a wide range of bioactive compounds, such as alkaloids, antibiotics, antifungals, immunomodulators, anticancer agents, enzymes, and vitamins. However, these compounds are often locked inside the fungal cell wall, which is composed of chitin, a tough substance that is dif�icult to digest by humans1. Therefore, it is essential to have a good extraction technique that can break down the chitin and release the valuable compounds from the fungi, this is especially essential in the laboratory for accurate lab assays and potency determination during routine HPLC chromatography analysis. During licensure and/ or certi�ication any given lab will be required to take a pro�iciency test which gauges the lab’s pro�iciency at measuring a given matrices for accurate evaluation. They evaluate our abilities to run the gear and accurately measure the potency of what was extracted; however, at the time of this writing none existed for extraction of the fungal material itself, so this remains a variable between testing labs. It is important that we openly share our extraction techniques for evaluating fungi materials speci�ically for the clean extraction of active alkaloids for which potency can be measure via chromatography and/or spectrometry devices. In this way hopefully creating less variables between testing lab and more concise results. In this paper, we present a novel sample prep and extraction technique for fungi that uses speci�ic solvent composition in conjunction with M.A.E (microwave assisted extraction) in 75% methanol , 25% water which helps break the cell wall to release the compounds. Also used is an ultrasonication unit and vortex mixer. Our technique quickly releases all the available alkaloids for accurate chromatography measurements in just two hours, forty-�ive minutes with minimal handling. We demonstrate the effectiveness and ef�iciency of our technique by applying it to magic mushroom fruit bodies for the extraction of tryptamines namely psilocybin and its active derivative psilocin; however, this technique can be used for other species of fungi and compounds like Cordyceps/ cordycepin or Lions’ mane/ erinacines, etc.. We also compare our technique with other popular methods in terms of extraction techniques, digestion times and solvent compositions. Our results show that our technique is superior to the others in terms of time and effectiveness while pulling all the active compounds and not degrading them. Our extraction technique for fungi chromatography analysis offers a new and improved way to access the natural products of fungi and explore their potential for various biotechnological applications. We hope that our technique will inspire further research and innovation in the field of fungal extraction and natural product.

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Lee, S. W. Supercritical fluid chromatographic analysis of aromatic ring type component of diesel fuels for an engine testing program to assess impact of fuel aromatics on diesel emissions. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1993. http://dx.doi.org/10.4095/304569.

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Horton, David, Victoria Soroker, Peter Landolt et Anat Zada Byers. Characterization and Chemistry of Sexual Communication in Two Psyllid Pests of Pears (Homoptera : Psyllidae). United States Department of Agriculture, août 2011. http://dx.doi.org/10.32747/2011.7592653.bard.

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Pear-feeding psyllids in the genus Cacopsylla (Hemiptera: Psyllidae) are among the most important arthropod pests of pears worldwide. These pests are exceedingly difficult to control, and new management tools are needed. Sex attractantpheromones have been used in IPM programs for pests of pome fruits (especially Lepidoptera), but not as yet for pest Hemiptera. Results of the current project showed that males of two psyllid pests of pears, Cacopsylla bidens (Israel) and Cacopsylla pyricola (North America), use volatile or semi-volatile compounds to locate female psyllids for mating. For both species, the attractants can be collected from the cuticle of females by washing live female psyllids with an appropriate solvent. Analysis of these washes by gas chromatography – mass spectrometry led to the following discoveries: Psyllid cuticles contain a mix of hydrocarbons, straight chain and branched alkanes, and long chain aldehydes The two species have different chemical profiles Chemical profiles change seasonally and with reproductive status Chemical profiles differ between male and reproductive female psyllids Several specific compounds found to be more abundant in attractive females than males were identified and synthesized. Behavioral assays (olfactometer) were then used to determine whether these compounds were attractive to males. Two compounds showed promise as attractants for male psyllids: 7-methylheptacosane (C. bidens) and 13-methylheptacosane (C. pyricola and C. bidens). These are the first sex attractantpheromones identified for any psyllid species. Field tests showed that the chemicals could be used to attract males under orchard conditions, but that effectiveness in the field appeared to be seasonally variable. Future research plans include: (a) test mixtures of compounds; (b) explore seasonality in field response to compounds; (c) determine whether chirality of the two compounds affects their attractiveness; and (d) compare different types of traps and release devices to optimize lure performance.

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Badrinarayanan et Olsen. PR-179-11201-R01 Performance Evaluation of Multiple Oxidation Catalysts on a Lean Burn Natural Gas Engine. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), août 2012. http://dx.doi.org/10.55274/r0010772.

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Two-way catalysts or oxidation catalysts are the common after-treatment systems used on lean burn natural gas engines to reduce CO, VOCs and formaldehyde emissions. The study evaluates the performance of oxidation catalysts from commercial vendors for varying catalyst temperature and space velocity. For this study, a part of the exhaust from a Waukesha VGF-18 GL lean burn natural gas engine was flowed through a catalyst slipstream system to assess the performance of the oxidation catalysts. The slipstream is used to reduce the size of the catalysts and to allow precise control of temperature and space velocity. Analyzers used include Rosemount 5-gas emissions bench, Nicolet Fourier Transform Infra-Red spectrometer and HP 5890 Series II Gas Chromatograph. The oxidation catalysts were degreened at 1200oF (650oC) for 24 hours prior to performance testing. The reduction efficencies for the emission species varied among the oxidation catalysts tested from different vendors. Most oxidation catalysts showed over 90% maximum reduction efficiencies on CO, VOCs and formaldehyde. VOC reduction efficiency was limited by poor propane emission reduction efficiency at the catalyst temperatures tested. Saturated hydrocarbons such as propane showed low reduction efficiencies on all oxidation catalysts due to high activation energy. Variation in space velocity showed very little effect on the conversion efficiencies. Most species showed over 90% conversion efficiency during the space velocity sweep. Adding more catalyst volume may not increase the reduction efficiency of emission species. Varying cell density showed very little effect on performance of the oxidation catalysts. The friction factor correlation showed the friction factor for flow through a single channel is inversely proportional to cell density.

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Fluhr, Robert, et Maor Bar-Peled. Novel Lectin Controls Wound-responses in Arabidopsis. United States Department of Agriculture, janvier 2012. http://dx.doi.org/10.32747/2012.7697123.bard.

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Innate immune responses in animals and plants involve receptors that recognize microbe-associated molecules. In plants, one set of this defense system is characterized by large families of TIR–nucleotide binding site–leucine-rich repeat (TIR-NBS-LRR) resistance genes. The direct interaction between plant proteins harboring the TIR domain with proteins that transmit and facilitate a signaling pathway has yet to be shown. The Arabidopsis genome encodes TIR-domain containing genes that lack NBS and LRR whose functions are unknown. Here we investigated the functional role of such protein, TLW1 (TIR LECTIN WOUNDRESPONSIVE1). The TLW1 gene encodes a protein with two domains: a TIR domain linked to a lectin-containing domain. Our specific aim in this proposal was to examine the ramifications of the TL1-glycan interaction by; A) The functional characterization of TL1 activity in the context of plant wound response and B) Examine the hypothesis that wounding induced specific polysaccharides and examine them as candidates for TL-1 interactive glycan compounds. The Weizmann group showed TLW1 transcripts are rapidly induced by wounding in a JA-independent pathway and T-DNA-tagged tlw1 mutants that lack TLW1 transcripts, fail to initiate the full systemic wound response. Transcriptome methodology analysis was set up and transcriptome analyses indicates a two-fold reduced level of JA-responsive but not JA-independent transcripts. The TIR domain of TLW1 was found to interact directly with the KAT2/PED1 gene product responsible for the final b-oxidation steps in peroxisomal-basedJA biosynthesis. To identify potential binding target(s) of TL1 in plant wound response, the CCRC group first expressed recombinant TL1 in bacterial cells and optimized conditions for the protein expression. TL1 was most highly expressed in ArcticExpress cell line. Different types of extraction buffers and extraction methods were used to prepare plant extracts for TL1 binding assay. Optimized condition for glycan labeling was determined, and 2-aminobenzamide was used to label plant extracts. Sensitivity of MALDI and LC-MS using standard glycans. THAP (2,4,6- Trihydroxyacetophenone) showed minimal background peaks at positive mode of MALDI, however, it was insensitive with a minimum detection level of 100 ng. Using LC-MS, sensitivity was highly increased enough to detect 30 pmol concentration. However, patterns of total glycans displayed no significant difference between different extraction conditions when samples were separated with Dionex ICS-2000 ion chromatography system. Transgenic plants over-expressing lectin domains were generated to obtain active lectin domain in plant cells. Insertion of the overexpression construct into the plant genome was confirmed by antibiotic selection and genomic DNA PCR. However, RT-PCR analysis was not able to detect increased level of the transcripts. Binding ability of azelaic acid to recombinant TL1. Azelaic acid was detected in GST-TL1 elution fraction, however, DHB matrix has the same mass in background signals, which needs to be further tested on other matrices. The major findings showed the importance of TLW1 in regulating wound response. The findings demonstrate completely novel and unexpected TIR domain interactions and reveal a control nexus and mechanism that contributes to the propagation of wound responses in Arabidopsis. The implications are to our understanding of the function of TIR domains and to the notion that early molecular events occur systemically within minutes of a plant sustaining a wound. A WEB site (http://genome.weizmann.ac.il/hormonometer/) was set up that enables scientists to interact with a collated plant hormone database.

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