SAMPLE MATRIX EFFECTS IN CAPILLARY ELECTROPHORESIS .1. BASIC CONSIDERATIONS

Serum samples contain high concentrations of proteins and ions which interfere in the analysis of small molecules such as theophylline. These effects are minimized by employing an electrophoresis buffer with high ionic strength. Although such buffers slow the speed of the analysis, they minimize the effects of proteins and ions, improve the separation and enable a larger volume of sample to be introduced into the capillary leading to enhanced signals. Therefore, serum samples can be diluted in weak buffers and analyzed directly rendering capillary zone electrophoresis an attractive technique in the clinical laboratories.