Jiyou Zhang

Quantification of glutathione and glutathione disulfide in human plasma and tobacco leaves by capillary electrophoresis with laser-induced fluorescence detection

A new capillary electrophoresis (CE) method with laser-induced fluorescence (LIF) detection was developed for the rapid separation and sensitive detection of glutathione (GSH) and glutathione disulfide (GSSH) after derivatization by 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol (NBD-Cl). The derivatization and separation conditions were investigated in detail and the optimums were obtained. Under the optimum experiment conditions, linear relationships between the peak height and concentrations of the analytes in normal and second-derivative electrophoregrams were obtained (0.22-45.00muM). The detection limits for glutathione and glutathione disulfide in normal and second-derivative electrophoregrams were 0.046 and 0.012muM and 0.046 and 0.014muM, respectively. The method was applied to the analysis of glutathione and glutathione disulfide in human plasma and tobacco leaves with satisfactory results.

Sensitive determination of ephedrine and pseudoephedrine by capillary electrophoresis with laser-induced fluorescence detection

A CE-LIF method was developed for the separation and sensitive detection of ephedrine and pseudoephedrine after derivatization by 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol (NBD-C1). The derivatization and separation conditions were investigated in detail and the optimum conditions were obtained. Under the optimum experiment conditions, good linearity relationships (correlation coefficients: 0.9942 for ephedrine and 0.9970 for pseudoephedrine) between the peak heights and concentrations of the analytes were obtained (0.7-140 microM). The detection limits were 0.16 microM for ephedrine and 0.17 microM for pseudoephedrine, which indicated that the sensitivities were at least ten times improved over those reported in the literature obtained by UV detection. The method was applied to the analysis of ephedrine and pseudoephedrine in ephedra herb plants and preparations with good results.

Microemulsion electrokinetic chromatography with laser-induced fluorescence detection for sensitive determination of ephedrine and pseudoephedrine.

A selective and sensitive microemulsion electrokinetic chromatography with laser‐induced fluorescence detection method was developed for the quantification of ephedrine (E) and pseudoephedrine (PE) derivatized with 4‐chloro‐7‐nitrobenzo‐2‐oxa‐1, 3‐diazol. By a series of optimization, a running buffer composed of 20 mM borate + microemulsion (23.3 mM Sodium dodecyl sulfate/180.85 mM 1‐butanol/16.4 mM n‐heptane) +8% acetonitrile was applied for the separation of the derivatives. A linear relationship for E and PE was obtained in the range of 0.058–11.58 μg·mL−1 (correlation coefficient: 0.9993 for E, 0.9995 for PE), and the detection limits for E and PE were 5.3 and 3.9 ng·mL−1. The method was applied to the analysis of the two alkaloids in Chinese traditional herbal preparations with recoveries in the range of 96.9–105.4%.

STUDIES OF THE CAPILLARY ELECTROPHORESIS BEHAVIOR OF SCOPOLAMINE-RELATED ANTICHOLINERGICS AND ITS APPLICATIONS

A simple and rapid capillary zone electrophoresis (CZE) method was proposed for the separation and quantitative analysis of atropine sulfate (AS), anisodamine hydrobromide (AH) and scopolamine hydrobromide (SH). The parameters affecting the migration behavior of these drugs were studied in detail, including the background electrolyte acidity and its concentration. In the optimized conditions, the method was used to determine the AS, AH and SH in various samples (Tablets, Injections and China herbal medicines of Hyoscyamus niger). The relative standard deviations of the migration time and the peak areas were 0.45–1.32% and 2.1–4.58%, respectively. The recovery of the three drugs ranges from 94.3 to 102.4%.