IMPROVEMENT OF SIGNAL-TO-NOISE RATIO OF ELECTROPHEROGRAMS AND ANALYSIS REPRODUCIBILITY WITH DIGITAL SIGNAL-PROCESSING AND MULTIPLE INJECTIONS

Poor signal-to-noise ratios and analytical reproducibility in capillar y electrophoresis were improved by application of multiple injections of the same sample at (pseudo) randomly chosen time moments. One order of signal-to-noise ratio improvement was achieved in practice using a n in-house developed computer-controlled pneumatic sampler. However, i t is demonstrated here that better implementation of the capabilities of multiple input requires that the detector signal noise be ''pre-whi tened'', i.e. spikes, baseline drift, oscillations etc, must be remove d from the detector signal before transforming it to the electropherog ram in the common form. Such filtering of the detector signal was real ized by implementing iterative, menu-driven software written in Matlab , a high-level programming language.