Serum antipyrine concentrations determined by micellar electrokinetic capillary chromatography

We developed an assay for antipyrine in serum using micellar electrokinetic capillary chromatography. A capillary electrophoresis system with a 70-cm fused-silica capillary and pH 8.2 borate-sodium dodecyl sulfate buffer was used. Standard curves ranging from 0.5 microgram/ml to 25 micrograms/ml were analyzed. The resulting electropherograms showed no interfering endogenous peaks and the assay was linear in the range of concentrations analyzed. The intra-day and inter-day relative standard deviations ranged from 0.7 to 5.2% and 1.7 to 8.1%, respectively. Analytical recovery of antipyrine ranged from 78.2 to 105.0%. The theoretical plate number for antipyrine was calculated to be 561,000 +/- 79,000 plates/m.