Determination of salicylic acid in human serum with capillary zone electrophoresis.

The determination of salicylic acid (SA), a metabolite of aspirin, in human serum was developed using capillary zone electrophoresis (CZE) with diode array detection. The reproducibility of separation and quantification with CZE analysis of the extract of SA from human serum was appropriate for the intra- and inter-day assay coefficients. A high correlation was revealed between the serum SA levels in volunteers determined by CZE and those determined by a fluorescence polarization immunoassay (r=0.973, n = 12), although the former values were slightly higher than the latter. There were no peaks interfering with the assay of SA by internal standard method. This CZE method could provide a simple and efficient method for monitoring SA in patients.