Core-based hyperbranched polyethyleneimine coating in capillary electrophoresis

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 11, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Sheryl A. TuckerVita.Ph.D. University of Missouri--Columbia 2009.In capillary electrophoresis (CE), chemical and dynamic modification of a fused silica surface can be used to control the electroosmotic flow (EOF), to minimize the interaction of analytes with the capillary surface and to modify the selectivity. , core-based hyperbranched polyethyleneimine (CHPEI) polymer utilized as either a static or dynamic coating in this study. A CHPEI-coated capillary was simply constructed in a rinsing fashion or by adding a small amount of CHPEI in a running buffer. In CHPEI-coated capillaries, several parameters were studied as follows: (1) EOF as a function of buffer pH; (2) effect of coating media (NaCl solution) concentration; (3) effect of buffer concentration; and (4) stability and reproducibility of the coating. Since CHPEI25-coated capillary provides greater EOF stability, CHPEI25 was chosen for further studies. The performance of CHPEI25 dynamic-, static-, and hybrid-coated capillaries was investigated in the separations of phenols, basic amino acids, B vitamins, aniline and its derivatives. The separation performance of CHPEI25 dynamic-coated capillaries were also compared to that of commercial eCAPTM capillary from Beckman Coulter. It is evident that CHPEI25 dynamic-coated capillary provides significantly improved peak resolution under identical separation conditions compared to that in eCAPTM.Includes bibliographical reference

CCQM-K138 : Determination of aflatoxins (AFB1, AFB2, AFG1, AFG2 and Total AFs) in Dried Fig. Key Comparison Track C. Final Report November 2018

Nine NMI/DI participated in the CCQM Organic Analysis WG Track C Key Comparison CCQM-K138 Determination of aflatoxins (AFB1, AFB2, AFG1, AFG2 and Total AFs) in Dried Fig. Participants were requested to evaluate the mass fractions expressed in ng/g units, of aflatoxins B1, B2, G1, G2 and total aflatoxin in a dried fig. Aflatoxins are part of the mycotoxin family of contaminants which are a major issue for the food production industry internationally. The CCQM-K138 results ranged from 5.17 to 7.27 ng/g with an %RSD of 10.47 for AFB1, ranging from 0.60 to 0.871 ng/g with an %RSD of 11.69 for AFB2, ranging from 1.98 to 2.6 ng/g with an %RSD of 10.36 for AFG1, ranging from 0.06 to 0.32 ng/g with an %RSD of 35.6 for AFG2, and ranging from 8.29 to 10.31 ng/g with an %RSD of 7.69 for Total AFs. All participants based their analyses on Liquid Chromatography, seven utilizing LC-MS/MS with labelled internal standards and two utilizing HPLC-FLD. Linear Pool estimators were used to assign the Key Comparison Reference Values (KCRVs) for B1, B2, G1, G2 and total aflatoxins. Successful participation in CCQM-K138 demonstrates the following measurement capabilities in determining mass fraction of organic compounds, with molecular mass of 100 g/mol to 500 g/mol, having high polarity (pKow > -2), in mass fraction range from 0.05 ng/g to 500 ng/g in dried food matrices. It was noted that the results for CCQM-K138 represent a highly challenging set of measurands and involve very low level measurement of complex analytes in a situation where there is very limited availability of appropriate calibration materials. Due to the variability in results the degrees of equivalence for these analytes were reasonably large and this will need to be taken into consideration in the assessment of proposed CMCs.Fil: Goren, Ahmet C. National Metrology Institute (TUBITAK UME); TurquíaFil: Gokcen, Taner. National Metrology Institute (TUBITAK UME); TurquíaFil: Gunduz, Simay. National Metrology Institute (TUBITAK UME); TurquíaFil: Bilsel, Mine. National Metrology Institute (TUBITAK UME); TurquíaFil: Koch, Mathias. Bundesanstalt fuer Materialforschung und –pruefung (BAM); AlemaniaFil: Kakoulides, Elias. Hellenic Metrology Institute; GreciaFil: Giannikopoulou, Panagiota. Hellenic Metrology Institute; GreciaFil: Tang Wai-tong, Gary. Government Laboratory of Hong Kong SAR (GLHK); ChinaFil: Chan, Andy. Government Laboratory of Hong Kong SAR (GLHK); ChinaFil: Kneeteman, Estela. Instituto Nacional de Tecnología Industrial (INTI); ArgentinaFil: Mugenya, Isaac. Kenya Bureau of Standards (KEBS); KeniaFil: Murııra, Geoffrey. Kenya Bureau of Standards (KEBS); KeniaFil: Boonyakong, Cheerapa. National Institute of Metrology of Thailand (NIMT); TailandiaFil: Fernandes-Whaley, Maria. National Metrology Institute of South Africa (NMISA); SudáfricaFil: Krylov, Anatoliy. D.I. Mendeleyev Institute for Metrology (VNIIM); RusiaFil: Mikheeva, Alena. D.I. Mendeleyev Institute for Metrology (VNIIM); Rusi

A simple and rapid colorimetric detection of methanol, ethanol, and isopropanol and its application toward alcohol-based hand sanitizer quality control

ABSTRACTA practical colorimetric analysis for alcohol determination was devised using a composite of food colorants, specifically a green solution of brilliant blue FCF and tartrazine at a ratio of 1:5 v/v. This colorimetric method was characterized by its simplicity, user-friendliness, environmental compatibility, cost-effectiveness, and suitability for self-measurement through visual examination. The colorimetric procedure entails admixture 1 mL of the alcohol sample with 50 µL of the green test solution and 250 µL of a 30% NaOH solution at ambient temperature. The ensuing color changes were visually assessed within 5 min. Through color sensing, methanol, ethanol, and isopropanol were identified by the manifestation of lemon yellow, orange, and biphasic solutions, respectively. Ethanol was semi-quantified based on color sensing from green to orange, with corresponding concentration ranges. The limit of detection for both methanol and ethanol was determined to be 30% v/v. The developed method demonstrated an accuracy of 93%, with the error range of 1 − 10% v/v and standard deviation of 3.9% v/v, as confirmed by the analysis of 100 commercially available alcohol-based hand sanitizers. This methodology has the potential for further expansion to encompass a wide range of rapid colorimetric analyses of products containing alcohol, including food items, alcohol raw materials, and cosmetics