The Experts below are selected from a list of 37632 Experts worldwide ranked by ideXlab platform
Georg W. Oertel - One of the best experts on this subject based on the ideXlab platform.
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Chromatography of uronic acids, sugar acid lactones, and glucuronosides on anion-exchange Paper or DEAE-cellulose.
Journal of Chromatography A, 2001Co-Authors: Georg W. OertelAbstract:Abstract For the separation of uronic acids, sugar acid lactones, and glucuronosides Paper Chromatography on anion-exchange Paper, such as Whatman ET-20, Whatman DE-20, and Schleicher & Schull Anionenaustauscher Papier with Dowex 2 X8 may be employed. Mixtures of alcohols, water, and organic acids or buffers were as mobile phases. In a similar manner, glucuronosides and glucuronic acid or glucuronic acid γ-lactone can be successfully chromatographed on columns of anion-exchange cellulose (Whatman DE-50 floc).
M Mersel - One of the best experts on this subject based on the ideXlab platform.
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separation and purification of dolichol and dolichyl phosphate by anion exchange Paper Chromatography application to cultured cells
Analytical Biochemistry, 1992Co-Authors: A Kupferberg, M L Tomassoni, M MerselAbstract:Abstract Dolichyl phosphate, dolichol C80–105 (dolichol 17:dihydroheptadecaprenol-dolichol 21:dihydrohexeicosaprenol), and dolichol C55 (dolichol 11:dihydroundecaprenol) were separated by anion-exchange Paper Chromatography. Squalene, sterols, phospholipids, anionic glycolipids, and glycerol did not migrate as dolichyl phosphate, dolichol C80–105, and dolichol C55 under our elution conditions. However, since the R f of triglycerides was similar to that of dolichol C80–105, saponification, prior to Chromatography, removed traces of triglycerides. Silica gel thin-layer Chromatography (TLC) allowed the separation of dolichol C80–105 from dolichol C55, whereas dolichyl phosphate was eluted with other lipids. Incubation of spontaneously transformed cells derived from rat astrocytes primary cultures with [2- 14 C]acetate, saponification of the extracted lipids, and anion-exchange Paper Chromatography revealed the presence of radioactive dolichyl phosphate and dolichol C80–105 (15 pmol/mg protein). Extraction of labeled dolichyl phosphate followed by acid phosphatase treatment and subsequent analysis on TLC confirmed the identity of dolichyl phosphate since all the radioactivity was associated with dolichol C55. Treatment of the transformed cells with 30 μ m 7-ketocholesterol or 7β-hydroxycholesterol stimulated markedly (two- to threefold) the incorporation of [2- 14 C]acetate in both dolichol C80–105 and dolichyl phosphate. These data demonstrate that anion-exchange Paper Chromatography is technically suitable for the separation and analysis of dolichol C55, dolichol C80–105, and dolichyl phosphate in cultured cells prelabeled with radioactive precursors.
A Kupferberg - One of the best experts on this subject based on the ideXlab platform.
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separation and purification of dolichol and dolichyl phosphate by anion exchange Paper Chromatography application to cultured cells
Analytical Biochemistry, 1992Co-Authors: A Kupferberg, M L Tomassoni, M MerselAbstract:Abstract Dolichyl phosphate, dolichol C80–105 (dolichol 17:dihydroheptadecaprenol-dolichol 21:dihydrohexeicosaprenol), and dolichol C55 (dolichol 11:dihydroundecaprenol) were separated by anion-exchange Paper Chromatography. Squalene, sterols, phospholipids, anionic glycolipids, and glycerol did not migrate as dolichyl phosphate, dolichol C80–105, and dolichol C55 under our elution conditions. However, since the R f of triglycerides was similar to that of dolichol C80–105, saponification, prior to Chromatography, removed traces of triglycerides. Silica gel thin-layer Chromatography (TLC) allowed the separation of dolichol C80–105 from dolichol C55, whereas dolichyl phosphate was eluted with other lipids. Incubation of spontaneously transformed cells derived from rat astrocytes primary cultures with [2- 14 C]acetate, saponification of the extracted lipids, and anion-exchange Paper Chromatography revealed the presence of radioactive dolichyl phosphate and dolichol C80–105 (15 pmol/mg protein). Extraction of labeled dolichyl phosphate followed by acid phosphatase treatment and subsequent analysis on TLC confirmed the identity of dolichyl phosphate since all the radioactivity was associated with dolichol C55. Treatment of the transformed cells with 30 μ m 7-ketocholesterol or 7β-hydroxycholesterol stimulated markedly (two- to threefold) the incorporation of [2- 14 C]acetate in both dolichol C80–105 and dolichyl phosphate. These data demonstrate that anion-exchange Paper Chromatography is technically suitable for the separation and analysis of dolichol C55, dolichol C80–105, and dolichyl phosphate in cultured cells prelabeled with radioactive precursors.
Yuqi Feng - One of the best experts on this subject based on the ideXlab platform.
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frontal elution Paper Chromatography for ambient ionization mass spectrometry analyzing powder samples
Analytical Methods, 2013Co-Authors: Yunqing Huang, Jinqing You, Yupeng Cheng, Wenjian Sun, Li Ding, Yuqi FengAbstract:We developed a convenient method by coupling frontal elution Paper Chromatography with desorption corona beam ionization mass spectrometry (FEPC/DCBI-MS) for rapid analysis of powder samples. In this method, the powder was deposited directly onto a coarse strip near the base of a triangular Paper sheet, and then a strong elution solvent was pipetted onto the base of the Paper sheet in the open air for developing. The sample zone migrated at the solvent front under strong elution conditions. Target analytes were finally condensed at the V-shaped tip which was then placed under the visible plasma beam of DCBI for ionization. Steps of solvent extraction and developing were performed on a Paper sheet simultaneously. The overall procedure requires less than two minutes. Signal intensities of target analytes were improved significantly due to analyte condensation at the tip and matrix effect reduction. Fundamentals and applications of FEPC/DCBI-MS were demonstrated by analysis of chlorphenamine in herbal medicines, clenbuterol in pig feed powder and nicotine in house-hold dust. The limits of detection ranged from 0.35 μg g−1 to 1.5 μg g−1 (0.52–2.2 ng, absolute) in full-scan positive-ion mode. The linear range was 5.0 μg g−1 to 5.0 × 102 μg g−1 with satisfactory linear coefficient (R2 = 0.885–0.956). Good reproducibility was achieved with relative standard deviations (RSDs) less than 20% and the recoveries ranged from 70 to 90%. The results demonstrate that the improved FEPC-DCBI-MS method is satisfactory for semi-quantitative evaluation of analytes in powder samples.
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coupling frontal elution Paper Chromatography with desorption corona beam ionization mass spectrometry for rapid analysis of chlorphenamine in herbal medicines and dietary supplements
Journal of Chromatography A, 2011Co-Authors: Yunqing Huang, Wenjian Sun, Li Ding, Jingqing You, Junsheng Zhang, Yuqi FengAbstract:We developed a convenient method by coupling frontal elution Paper Chromatography with desorption corona beam ionization mass spectrometry (DCBI-MS) for rapid determination of chlorphenamine added in herbal medicines or dietary supplements. In this method, the ethanol extract of the herbal products was spotted directly onto an isosceles triangular filter Paper sheet, and then the Paper sheet was developed under strong elution condition with the sample zone migrating at the solvent front. The analyte was finally condensed at the V-shaped tip which could then be placed under the visible plasma beam of DCBI for ionization. The overall procedure took less than 5 min. The frontal elution Paper Chromatography on a triangular plate used in this work improved the signal intensity of chlorphenamine by 30-fold due to the analyte condensing at the tip and the reduction of the background suppression. Furthermore, the Paper sheet also functioned as a filter in the analysis of solid or powder samples, which can increase the analytical throughput by omitting the step of centrifugation. The proposed method in current study was successfully applied in the determination of chlorphenamine in herbal medicines. Chlorphenamine was detected in four of the twelve types of herbal medicines examined in this study. The limit of detection was 200 ng/mL (2.0 ng absolute) in full-scan positive-ion mode and the linear range was from 5.0 μg/mL to 50 μg/mL with satisfactory linear coefficient (R(2) (the square of the correlation coefficient)=0.895). Good reproducibility was achieved with relative standard deviations (RSDs) less than 15.0% and the recoveries of chlorphenamine ranged from 84.3 to 90.6%.
M L Tomassoni - One of the best experts on this subject based on the ideXlab platform.
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separation and purification of dolichol and dolichyl phosphate by anion exchange Paper Chromatography application to cultured cells
Analytical Biochemistry, 1992Co-Authors: A Kupferberg, M L Tomassoni, M MerselAbstract:Abstract Dolichyl phosphate, dolichol C80–105 (dolichol 17:dihydroheptadecaprenol-dolichol 21:dihydrohexeicosaprenol), and dolichol C55 (dolichol 11:dihydroundecaprenol) were separated by anion-exchange Paper Chromatography. Squalene, sterols, phospholipids, anionic glycolipids, and glycerol did not migrate as dolichyl phosphate, dolichol C80–105, and dolichol C55 under our elution conditions. However, since the R f of triglycerides was similar to that of dolichol C80–105, saponification, prior to Chromatography, removed traces of triglycerides. Silica gel thin-layer Chromatography (TLC) allowed the separation of dolichol C80–105 from dolichol C55, whereas dolichyl phosphate was eluted with other lipids. Incubation of spontaneously transformed cells derived from rat astrocytes primary cultures with [2- 14 C]acetate, saponification of the extracted lipids, and anion-exchange Paper Chromatography revealed the presence of radioactive dolichyl phosphate and dolichol C80–105 (15 pmol/mg protein). Extraction of labeled dolichyl phosphate followed by acid phosphatase treatment and subsequent analysis on TLC confirmed the identity of dolichyl phosphate since all the radioactivity was associated with dolichol C55. Treatment of the transformed cells with 30 μ m 7-ketocholesterol or 7β-hydroxycholesterol stimulated markedly (two- to threefold) the incorporation of [2- 14 C]acetate in both dolichol C80–105 and dolichyl phosphate. These data demonstrate that anion-exchange Paper Chromatography is technically suitable for the separation and analysis of dolichol C55, dolichol C80–105, and dolichyl phosphate in cultured cells prelabeled with radioactive precursors.
