Authors:Xiaobin Li, Fangfang Gao, Huitao Liu, and Yuan Gao
tandem MS is the most selective and sensitive technique for identification and quantification of HCP. But compared with capillaryelectrophoresis (CE), HPLC has the disadvantages of consuming a large amount of organic solvent, long analysis time and more
High-performance capillary electrophoresis with amperometric detection (CE-AD) has been used for analysis of eight bioactive components of the leaves, stems, and roots of Valeriana wallichii DC, after a relatively simple extraction procedure with ethanol. Under the optimum conditions, the eight components can be well separated or (apigenin and luteolin) separated nearly to baseline within 23 min by use of 50 mM borax (pH 9.2) as running buffer and a separation potential of 16 kV. Linearity was excellent over two orders of magnitude of concentration and detection limits (S/N = 3) ranged from 1.7 × 10−7 to 1.8 × 10−8 g mL−1. This method was used for comparison of the concentrations of the bioactive compounds in different parts of the plant on the basis of their electropherograms or ‘characteristic electrochemical profiles’. Assay results were satisfactory.
Authors:T. W. Inglot, A. Gumieniczek, Ł. Komsta, and R. Związek
Comparison of classical densitometry, video-scanning, and capillary electrophoresis was performed for determination of angiotensin II receptor antagonist, valsartan, and calcium channels blocker, amlodipine, in a combined dosage form. Thin layer chromatography was performed on RP8F254 TLC plates with a mobile phase consisting of acetonitrile-phosphate buffer at pH 9.0 (5:5, v/v) and temperature 20 °C. Densitometry was done in the reflectance mode at 217 nm for valsartan and in the absorbance mode at 370 nm for amlodipine. Video-scanning was elaborated at 254 and 366 nm for valsartan and amlodipine, respectively. For chromatographic analysis, calibration plots were constructed in the range of 0.4–2.8 μg per spot for valsartan and 0.02–0.14 μg per spot for amlodipine. Capillary electrophoresis (CE) was performed using a 75 μm × 94 cm fused silica capillary (72 cm effective length), 0.01 mol L−1 borate buffer at pH 8.0, 20 kV voltage, 30 °C temperature, hydrodynamic injection (10 mbar, 6 s) and UV detection at 237 nm. Calibration plots were constructed in the range of 0.1–0.6 mg mL−1 for valsartan and 0.005–0.03 mg mL−1 for amlodipine. All methods were validated in respect to robustness, specificity, stability, linearity, precision, and accuracy. Generally, statistical comparison between the methods did not show significant differences so all procedures are suitable for pharmaceutical analysis.
Authors:M. Jaworska, Z. Szulińska, M. Wilk, and E. Anuszewska
Because of the problems with stability and solubility, some of the amino acids (AAs) used in parenteral nutrition products are often replaced by their acetylated forms. These include N-acetyltyrosine (NAT) and N-acetylcysteine (NAC). This leads to a need to develop new analytical methods for rapid and easy determination of these substances in the presence of common AAs. Capillary electrophoresis (CE) is one of the techniques that have been successfully applied to the assay of multi-component samples containing AAs and their derivatives. This paper discusses a new CE method for the simultaneous determination of two acetylated AAs in solutions for parenteral nutrition. A background electrolyte (BGE) was developed based on borate buffer with alkaline pH. The method is selective and enables the separation and assay of analytes without special sample pretreatment. Validation parameters confirmed sufficient precision and accuracy of the method. Its applicability was verified by testing several medicinal products from various manufacturers. Moreover, the flexibility of the method was checked using two brands of CE equipment. Appropriate adjustment of instrumental parameters turned out to be essential for method transferability. The method could be used in routine testing of parenteral nutrition medicinal products containing AAs.
Authors:Y. Wen, H. Liu, L. Tian, P. Han, and F. Luan
A simple and rapid capillary electrophoretic procedure for analysis of matrine and oxymatrine in Kushen medicinal preparations has been developed and optimized. Orthogonal design was used to optimize the separation and detection conditions for the two active components. Phosphate concentration, applied potential, organic modifier content, and buffer pH were selected as variable conditions. The optimized background electrolyte contained 70 mM sodium dihydrogen phosphate and 30% acetonitrile at pH 5.5; the separation potential was 20 kV. Each analysis was complete within 5 min. Regression equations revealed linear relationships (r > 0.999) between peak area and amount for each component. The detection limits were 1.29 μg mL−1 for matrine and 1.48 μg mL−1 for oxymatrine. The levels of the two active compounds in two kinds of traditional Chinese medicinal preparation were easily determined with recoveries of 96.57–106.26%. In addition, multiple linear regression and a non-linear model using a radial basis function neural network approach were constructed for prediction of the migration time of oxymatrine. The predicted results were in good agreement with the experimental values, indicating that a radial basis function neural network is a potential means of prediction of separation time in capillary electrophoresis.
Authors:Haya I. Al-Johar, Hadir M. Maher, Nourah Z. Al-Zoman, Dlayel J. Al-Shammary, and Hessa Al-Showiman
(LC–MS) [18–20], ultra-performance liquid chromatography (UPLC) , high-performance thin-layer chromatography (HPTLC) [22–24], and spectrophotometry [25–30].
To our knowledge, the use of capillaryelectrophoresis (CE) to determine FTC and
An ultrasensitive and rapid method for the determination of epicatechin, rutin, and quercetin was developed using capillary zone electrophoresis with on-line chemiluminescence detection. Under the optimal conditions, the analytes were baseline separated within 12 min. The limits of detection in turn were 0.60 pg mL−1 for epicatechin, 0.50 pg mL−1 for rutin, and 1.0 pg mL−1 for quercetin. The developed method was an easy and reliable method of determining these analytes concentrations in tea, extract Ginkgo biloba, and rutin tablet, demonstrating the feasibility and reliability of the proposed method.
Authors:Huitao Liu, Yingying Wen, Feng Luan, and Yuan Gao
A simple and rapid capillary zone electrophoretic method is proposed for the analysis of antioxidants and preservatives in food. The important factors affecting separation and detection, for example pH, and concentration of the buffer electrolyte and organic modifier, were investigated in detail. Separation of five antioxidants (propyl gallate, gallic acid isoamyl ester, gallic acid n-octyl ester, nordihydroguaiaretic acid, and trihydroxybutyrophenone) and one preservative (benzoic acid) was achieved in a 50.5 cm (effective length) × 75 μm i.d fused-silica capillary, with 15 mmol L–1 borate buffer, pH 9.18, containing 25% (v/v) acetonitrile as separation buffer. UV detection was at 219 nm and the applied potential was 25 kV. Regression analysis revealed linear relationships between peak area and amount of each additive from 10 to 1000 μg mL–1 (R = 0.9992–1.0000). RSD of retention time and peak area were 0.44–0.74% and 1.25–4.31%, respectively. The method was successfully used for simultaneous analysis of the six compounds in food with the recoveries from 89.3 to 115.8%.
Capillary electrophoresis with fluorescence detection has been investigated for simple, sensitive, and selective analysis of morphine and 6-acetylmorphine (6-AM) in human urine. The method is based on the reaction of morphine and 6-AM with the freshly prepared diazonium salt of aniline at 0°C. The method is selective in the presence of codeine. Conditions that affect derivatization (diazonium concentration and reaction time) and separation (electrolyte concentration, pH, β-cyclodextrin concentration, organic additives, and separation potential) were studied. When fluorescence detection was used with an excitation wavelength of 350 nm and an emission cutoff filter of 500 nm, good linearity was obtained in the range of 50–2000 ng mL–1 with limits of detection and quantification below 1.0 and 3.3 ng mL–1, respectively. The method was applied to human urine and validated by comparison with previously established capillary electrophoretic methods. Accuracy, repeatability, and intermediate precision of results were comparable. The method is suitable for application in forensic cases for initial screening, and in clinical analysis to prevent overdose-induced toxicity.