Determination of sulphonamides in pork meat extracts by capillary zone electrophoresis

For 16 sulfonamides the effective mobility was measured as a function of pH and from the effective mobilities detd. in 2 electrolyte systems the pK value and mobility at infinite diln. were calcd. A pH of 7.0 was optimum for the sepn. of both std. mixts. and mixts. of sulfonamides dissolved in pork meat exts. For the detn. of the sulfonamides in pork, only a very simple sample pretreatment, consisting of extn. with MeCN and centrifugation, is suitable as the matrix effects at pH 7.0 do not affect the sepn. Calibration graphs for 5 sulfonamides were constructed, and regression coeffs. of at least 0.999 were obtained. The limit of detection was 2-9 ppm for a pressure injection time of 10 s (injection vol. .apprx.18 nL) by using a Polymicro Technol. capillary 116.45 cm long, with a distance between injection and detection of 109.75 cm and an internal diam. of 50 mm