A COMPUTER-CONTROLLED HIGH-VOLTAGE EQUIPMENT FOR CAPILLARY ELECTROPHORESIS AND ELECTROCHROMATOGRAPHY

An equipment is designed and evaluated for the separation of biomolecules by capillary electrophoresis and electrochromatography. The major components of the equipment are: (a) a high-voltage dc power supply with reversible polarity output, (b) a computer controlled power supply and data acquisition interface using an IEEE-488 General Purpose Instrumentation Bus, and (c) a chromatography system (elution pump, sample injector, capillary and chromatography columns, temperature controller, and effluent monitor). The software written in Microsoft C for the control of this equipment has three distinct features: one, precision control of the high voltage, two, generation of high-voltage waveforms, and three, constant monitoring of the set voltage and current values. The equipment is versatile and applicable for liquid chromatography and capillary electrophoresis utilizing columns and capillaries of different dimensions and properties. It performs data acquisition in real time on two channels and controls the power supply at the same time. The novelty of the equipment lies in the availability of a wide variety of high-voltage waveforms which can be used to control the heat and reduce the band spreading in chromatography. The use of this equipment has been studied for the separation of a mixture of deoxymononucleotides on a chromatography column, while applying a bidirectional electric potential.