Capillary Electrophoresis Articles

A simple capillary zone electrophoresis method is discussed for the simultaneous analysis of omeprazole and lansoprazole.

A simple capillary zone electrophoresis method (CZE) was established for simultaneous analysis of omeprazole (OM) and lansoprazole (LA). Untreated fused-silica capillary was operated using a phosphate buffer (50 mM, pH 9.0) under 20 kV and detection at 200 nm. Baseline separation was attained within 6 min. In method validation, calibration curves were linear over a concentration range of 5 to 100 µM, with correlation coefficients 0.9990. Relative standard deviation (RSD) and relative error (RE) were all less than 5% for the intra-day and inter-day analysis, and all recoveries were greater than 95%. The limits of detection for both omeprazole and lansoprazole were 2.0 µM (S/N = 3, hydrodynamic injection 5 s). This method was applied to determine the quality of commercial capsules. Assay results fell within 94–106%.

Life on earth is currently estimated to have begun approximately 3.8 billion years ago.1 Protists were the first single cells of eukaryotic origin. Though many of these organisms are only composed of one single cell, their importance extends beyond their relative simplicity. In fact, they serve as the basis for the ecology of advanced organisms. The questions what is life and how does it originate point to the paradox inherent in the single cell. Modern science has yet to uncover a completely satisfying response. If such questions are so difficult to answer, it stands to reason that single-celled organisms — among the simplest eukaryotic species on earth — must in reality be incredibly complex. The human desire for self-understanding, down to the simplest biological building block, promotes extensive single-cell study within the research community.

Introduction :

Capillary electrophoresis (CE) is a relatively new technique, which has expanded considerably in the last decade. Such rapid development is the result of several factors: sample preparation is reduced to a minimum, separation can usually be achieved quickly and solvent requirements are minimal. With the method we have developed to analyse citrus juices, preparation requires only filtration and dilution. The separation is rapid, up to thirty citrus juice compounds can be separated in 20 min. There is no reconditioning period between each analysis and after a 3 min wash a new sample can be started. These CE characteristics are well suited for continuous analysis with little intervention from the analyst. Finally, the use of the instrument is very cost effective. Seventy centimetres of bare fused-silica capillary cost very little and the same tubing can be used for several years, if maintained properly.

A capillary electrophoresis method using the CElixir buffer system for the analysis of propranolol in human serum was compared with a method using phosphate buffer. While both methods showed good linearity over the concentration range tested, the CElixir method showed better accuracy and precision at the low concentration end (25–50 ng/mL). The limits of quantitation and detection of the CElixir method were 25 and 12.5 ng/mL, respectively. Improved migrationtime reproducibility was obtained with the CElixir method, which was probably responsible for an enhanced overall performance compared with the standard phosphate method.

Introduction :
Capillary electrophoresis (CE) is gaining wider acceptance in analytical laboratories and has become an important tool for routine analysis in the pharmaceutical and biotech industries1.

Co-authored by separation scientists at three pharmaceutical companies, this instalment of “CE Currents” describes how these companies have successfully adopted capillary electrophoresis for routine analysis. The column discusses using capillary electrophoresis to support aspects of early drug discovery testing, to analyse protein-based pharmaceuticals, and to support drug development and routine quality control of marketed pharmaceuticals.

This “CE Currents” column examines the use of capillary electrophoresis (CE) in three important areas of pharmaceutical analysis. The first section deals with using CE to support aspects of early drug discovery testing, and it uses examples from Cardiome Pharma Corp. (Vancouver, British Columbia, Canada). The second section concentrates on using CE to analyse protein-based pharmaceuticals, a fastgrowing area, and it incorporates several examples from Genentech Inc.

Since the introduction of commercial capillary electrophoresis (CE) systems over 10 years ago, separation mechanisms have become more clearly understood, and can now be modelled, simulated and thus controlled. However, it is important to think in terms of the “CE world” when troubleshooting CE methods rather than using conventional “chromatography-mode thinking”. Raw electrophoretic data transformation into the effective mobility scale is a first step towards better reproducibility for both qualitative and quantitative analyses. Application examples are used to illustrate the power of this data transformation tool.

Introduction :
“CE-mode thinking”, as termed by Whatley (1), is a prerequisite for handling capillary electrophoresis (CE) problems and obtaining robust results. Acquiring good reproducibility in migration times (qualitative aspects) and peak integration (quantitative aspects) forms part of this goal.

This month’s instalment of “CE Currents” deals with problems that may arise when using capillary electrophoresis for unattended, long-term operation. The guest authors look at issues such as sample carryover, evaporation effects, capillary conditioning, capillary surface changes, buffer handling, capillary breakage and detector-lamp deterioration. They provide several technical recommendations for stabilizing the electrophoretic system and increasing reproducibility.

Because commercial capillary electrophoresis (CE) instruments have been available for a decade, CE has become a mature and well-established analytical tool. CE is extensively used for routine analysis as an alternative or complementary technique to high performance liquid chromatography (HPLC). Many of the technical problems have been solved, and handling the instruments has become effortless.