Jinying Sun

Analysis of amphetamines in urine with liquid-liquid extraction by capillary electrophoresis with simultaneous electrochemical and electrochemiluminescence detection

Amphetamines including methamphetamine, 3,4‐methylenedioxyamphetamine and 3,4‐methylenedioxymethamphetamine were separated and detected by CE using simultaneous electrochemical (EC) and electrochemiluminescence (ECL) detection (CE‐EC/ECL). Factors that influenced the separation and detection performance, such as the detection potential, the pH value and concentration of the running buffer, the separation voltage and the pH of the detection buffer, were investigated. LODs of 3.3×10−8 mol/L (0.16 fmol), 1.6×10−7 mol/L (0.78 fmol) and 3.3×10−8 mol/L (0.16 fmol) were obtained for methamphetamine, 3,4‐methylenedioxyamphetamine and 3,4‐methylenedioxymethamphetamine, respectively. For practical application, a liquid–liquid extraction with ethyl acetate procedure was developed for urine sample pretreatment and extraction efficiencies higher than 90% were obtained. The established simultaneous CE‐EC/ECL was successfully applied for urine sample analysis.

A novel technique for NACE coupled with simultaneous electrochemiluminescence and electrochemical detection for fast analysis of tertiary amines

A simultaneous electrochemiluminescence (ECL) and electrochemical (EC) detection scheme for NACE was presented for fast analysis of tertiary amines. Both ECL and EC signals were generated at the same Pt electrode. Triethylamine (TEA), tripropylamine (TPrA), chlorpromazine, promethazine, and dioxopromethazine (DPZ) were selected to validate NACE–ECL/EC dual detection strategy. The linear ranges for TEA and TPrA were 0.01–500 and 0.01–10 μM with the detection limits of 8.0 and 5.0 nM (S/N=3), respectively. The RSDs (n=6) of the migration time and the ECL intensity for 1 μM TEA and 0.5 μM TPrA were 0.1 and 2.8%, and 0.2 and 1.8% with theoretical plate numbers of 180 000 and 700 000 per meter, respectively. These two analytes could be separated within 92 s and the Pt electrode did not need reactivation during the experiments. Chlorpromazine, promethazine, and DPZ could be well separated by NACE. The proposed method was also demonstrated for fast determination of DPZ in human urine with simple sample preparation. The results indicated that NACE–ECL/EC had the advantages of simple and fast analysis with more information, wide linear range, high sensitivity, and compatibility with real urine sample.

Chemometrics optimization of six antihistamines separations by capillary electrophoresis with electrochemiluminescence detection.

This work expanded the knowledge of the use of chemometric experimental design in optimizing of six antihistamines separations by capillary electrophoresis with electrochemiluminescence detection. Specially, central composite design was employed for optimizing the three critical electrophoretic variables (Tris-H(3)PO(4) buffer concentration, buffer pH value and separation voltage) using the chromatography resolution statistic function (CRS function) as the response variable. The optimum conditions were established from empirical model: 24.2mM Tris-H(3)PO(4) buffer (pH 2.7) with separation voltage of 15.9 kV. Applying theses conditions, the six antihistamines (carbinoxamine, chlorpheniramine, cyproheptadine, doxylamine, diphenhydramine and ephedrine) could be simultaneous separated in less than 22 min. Our results indicate that the chemometrics optimization method can greatly simplify the optimization procedure for multi-component analysis. The proposed method was also validated for linearity, repeatability and sensitivity, and was successfully applied to determine these antihistamine drugs in urine.

Determination of nicotine and its metabolite cotinine in urine and cigarette samples by capillary electrophoresis coupled with electrochemiluminescence

In this paper, CE coupled with electrochemiluminesence (ECL) detection using a 76‐μm Pt disk as working electrode was developed for nicotine (NIC) determination. The major metabolite of NIC is cotinine (COT), which has a similar tertiary amine structure to NIC. However, there is a carbonyl group attached in the structure of COT, which leads to the great decrease in ECL response. In order to improve the ECL response of COT, NaBH4 was used for carbonyl reduction. After reduction, NIC and COT were separated and detected by CE‐ECL. ECL response plotted with NIC concentration was linear between 5.0×10−7 and 5.0×10−5 mol/L (81–8100 μg/L), with LOD of 5.0×10−8 mol/L (8.1 μg/L). The developed CE‐ECL method was applied for NIC determination in urine and cigarette samples.

Recent progress for capillary electrophoresis with electrochemical detection

AbstractCapillary electrophoresis (CE) is an attractive technique in separation science because of its high separation performance, short analysis time and low cost. Electrochemical detection (EC) is a powerful tool for CE because of its high sensitivity. In this review, developments of CE-EC from 2008 to August, 2011 are reviewed. We choose papers of innovative and novel results to demonstrate the newest and most important progress in CE-EC.

Quality Analysis of Herbal Medicine Products Prepared from Herba Sarcandrae by Capillary Electrophoresis with Electrochemical Detection

Abstract A capillary electrophoresis with electrochemical detection(CE-ED) method was developed for the quality analysis of herbal medicine products prepared from the same herb of Herba Sarcandrae: Fufang Caoshanhu tablets, Qingrexiaoyanning capsules, and Xuekang oral liquids. Under the optimal analysis conditions, the low detection limit[1.0x10−7 mol/L(S/N=3)] and the wide linear range(1.0x10−7—1.0x10−4 mol/L) were obtained for quality standard compound of isofraxidin. The precisions of the peak current and the migration time(as RSDs) for the real sample analysis were 2.0%—2.6%, and 1.2%—1.8% for isofraxidin, respectively. The contents of isofraxidin detected were 15.77 μg/tablet, 0.48 mg/capsule, 1.2 mg/ampoule(Jiangxi), and 0.44 mg/ampoule(Dalian) for Fufang Caoshanhu tablets, Qingrexiaoyanning capsules, and Xuekang oral liquids from different manufacturers, respectively. Quality estimate was conducted by comparing the contents of isofraxidin in the herbal medicine products with the demanded values of Chinese pharmacopeia. In addition, based on their own unique CE-ED profiles(namely, CE-ED electropherograms) the Xuekang oral liquids from the different manufacturers could be easily identified.