Miniaturized on-line capillary electrophoresis instrument

The need to control physical and chemical phenomena requires on-line instruments or modifications of existing commercial instruments to on-line purposes. Capillary electrophoresis (CE) has demonstrated its potential as a significant technique for a variety of analyses due to especially its high speed and ease of automation. In this study, we have developed, built and tested an on-line CE instrument, which is suitable for on-line control of indutrial processes. The instrument is constructed from two identical solvent modules for electrolyte solutions and sample made of PMMA polymer. They are on-line coupled with the ends of an installation module designed for a capillary and an UV or a LIF detector. A peristaltic pump is used to feed the solutions. Samples are injected with the aid of a loop and electrical actuated valve. A thermostated box for the whole module system and the solvent reservoirs, an UV detector, computer controller and data processing units are modified for the instrument. The peristaltic pump, a sampling valve and the on-line modules are connected with Teflon tubes to a 6-way low pressure selection valve allowing selection of solvents for conditioning, rinsing and separation stages. The miniaturized on-line CE system has been used in monitoring water-soluble anions in pulp and paper processes at mills.