capillary zone electrophoresis

The development of a new assay for lipoproteins by capillary electrophoresis in fused-silica capillaries and in glass microdevices is described in this paper. The separation of low-density (LDL) and high-density (HDL) lipoproteins by capillary zone electrophoresis is demonstrated in fused-silica capillaries with both UV absorption and laser-induced fluorescence detection. This separation was accomplished using Tricine buffer (pH 9.0) with methylglucamine added as a dynamic coating. With UV detection, LDL eluted as a ...

Hemoglobin A2 (Hb A2) and hemoglobin F (Hb F) are important analytes in the diagnosis and follow up of Hb diseases. We evaluated a new capillary zone electrophoresis (CZE) kit for Hb A2 and Hb F measurements. The imprecision ranged from 3% to 6% for Hb A2 and Hb F at physiological and pathological concentrations. The method compared well with cation-exchange HPLC for Hb A2 and Hb F and with anion-exchange chromatography in microcolumns (MAEC), for Hb A2. Nevertheless, higher results were obtained [Hb A2 CZE (%) = 1.233 Hb A2 HPLC - 0.2; Hb A2 CZE (%) = 1.190 Hb A2 MAEC + 0.1; Hb FCZE (%) = 1.118 Hb FHPLC + 0.4], and new reference values had to be determined (Hb A2 2.7-3.8%; Hb F <1.2%). Quantification of Hb A2 was not influenced by Hb S. Measurement of Hb F was accurate and precise except at low concentrations in Hb AS patients. This new CZE kit is rapid, precise, and reliable, and seems appropriate for use in clinical laboratories.

A simple and rapid stability indicating method based on capillary zone electrophoresis has been developed and validated for the analysis of buserelin (BUS). The best separations were achieved by using a bare fused silica capillary (75 μm i.d.; 65.5 cm total, 57.0 cm effective length), phosphate buffer (pH = 3.00; 26.4 mM), at 35 °C. The sample was hydrodynamically injected at 50 mbar for 5 seconds; the applied voltage was 30 kV and detection was carried out by UV-absorbance at 200 nm. Method validation resulted in the following figures of merit : the method was linear in the concentration range between 0.781 and 500 μg/mL (linear regression coefficient 0.9996), accuracy was between 99.3% and 100.9%, intra assay precision was between 0.3% and 1.0% and intermediate precision was between 1.0% and 2.1%. Evaluation of the specificity of the method showed no interference between excipients or products of force degradation and BUS. Under the selected conditions, separation of BUS and its d...

Experimental evidence suggests that release of neurotransmitters in response to acute noxious stimulation and inflammation can differ in superficial and deeper dorsal horn (DH) laminae. Using two different microdialysis probes, we studied changes in levels of ...

Three machine learning techniques including back propagation artificial neural network (BP-ANN), radial basis function artificial neural network (RBF-ANN) and support vector regression (SVR) were applied to predicting the peptide mobility in capillary zone electrophoresis through the development of quantitative structure-mobility relationship (QSMR) models. A data set containing 102 peptides with a large range of size, charge and hydrophobicity was used as a typical study. The optimal modeling parameters of the models were determined by grid-searching approach using 10-fold cross-validation. The predicted results were compared with that obtained by the multiple linear regression (MLR) method. The results showed that the relative standard errors (R.S.E.) of the developed models for the test set obtained by MLR, BP-ANN, RBF-ANN and SVR were 11.21%, 7.47%, 5.79% and 5.75%, respectively, while the R.S.E.s for the external validation set were 11.18%, 7.87%, 7.54% and 7.18%, respectively....

Microorganisms like bacteria, viruses, fungi, etc. have a major impact on human, animal, and plant life. Several decades ago it was observed that intact cells suspended in an isotonic salt solution moved toward the anode and the mobility was proportional to the density of the charge located on the cell surfaces. Since then, efforts have been made to make electrophoresis a useful tool in cell studies. Microorganisms are no exception. In the present work we applied the capillary zone electrophoresis (CZE) with dynamical modification of the capillary surface for separation of E. coli and P. vulgaris. The same method was used for identification of E. coli in infected urine (direct injection--UTIs) and also for identification of Helicobacter pylori which is a gram-negative bacillus responsible for one of the most common infections found in humans worldwide. Using spectrophotometric measurements at lambda = 214 nm we proved that it is possible to measure the concentration of bacterial cells up to 5 x 10(8) cells/mL. Recent studies have demonstrated very practical uses for electrophoretic techniques, especially in the field of medical diagnosis.

A simple and robust solid‐phase extraction (SPE) procedure for the cleanup and sample preconcentration of antifungals (ketoconazole, clotrimazole, itraconazole, fluconazole, and voriconazole) and their metabolites after incubation with human liver microsomes, as well as a simplified capillary zone electrophoresis (CZE) method for their rapid analysis, have been developed to determine the stability of these compounds in in vitro samples. Three different sample pretreatment procedures using SPE with reversed‐phase sorbents (100 mg C8, 100 mg C18, and 30 mg Oasis‐HLB) were studied. The highest and most reproducible recoveries were obtained using a 30 mg Oasis‐HLB sorbent and methanol containing 2% acetic acid as eluent. Enrichment by a factor of about four times was achieved by reconstituting the final SPE eluates to a small volume. For the CZE separation, good separations without interfering peaks due to the in vitro matrix were obtained with a simple running electrolyte using a fused...

Methods of electromigration in laboratory apparatus of small-bore size have recently undergone development at a remarkably rapid pace, leading to a variety of new analytical techniques. One such technique is called “capillary electrophoresis” (CE), which is further classified on the basis of electromigration mode, viz., “capillary zone electrophoresis” (CZE), which, in turn, has several variations. This review aims to give a short overview of the various electromigration methods for amino compounds by using CE. Firstly, this review briefly summarizes the detection methods employed for detection of monoamines and polyamines by CE for both native and derivative forms. Next, current CE methods are described, and their applications to detection of amino acids, biogenic amines, aromatic amines, including heteroaromatic amines and their enantiomers, are introduced from representative papers. Finally, new methods for single-cell analysis and microchip CE techniques are focused on.