Operating parameter effects in capillary zone electrophoresis (CZE): Analysis of pentamidine, hydroxystilbamidine, propamidine, DAPI, and stilbamidine in body fluids

A study was undertaken of the effects of varying those parameters that most affect analyses by capillary zone electrophoresis (CZE), electrolyte buffe r, concentration of electrolyte, pH, voltage, temperature, and diameter of capillary, in respect to the following aromatic diamidines of therapeutic v alue: pentamidine, hydroxystilbamidine, propamidine, 6-amidino-2- (4-amidin ophenyl) indole dilactate (DAPI), and stilbamidine. The data obtained permi t the design of specific analytic methodology for each of these chemicals u nder differing conditions. As a demonstration, an analytical method is prop osed in which all these chemicals are analyzed, simultaneously, in serum an d urine under the following CZE conditions: citrate buffer 25 mM, pH = 3.75 , T = 30 degreesC, and V = 14 kV. The detection limits for the method for s erum and urine are (mug/mL): pentamidine, 0.3; hydroxystilbamidine, 0.4; pr opamidine, 0.2; DAPI, 0.3; and stilbamidine, 0.3. Oasis HLB cartridges were used for prior treatment of both serum and urine samples.