An automated potentiometric assay for acid phosphatase.

Two flow injection systems for detection of acid phosphatase (ACP) activity have been investigated. In both systems, monofluorophosphate (MFP) as a specific and inexpensive substrate for ACP and LaF(3) membrane-based ion-selective electrode as a potentiometric detector of fluoride ions released in the course of the biocatalytic hydrolysis of MFP were applied. The continuous-flow mode was modified to include a stopped-flow segment, with separate valve control, to increase reaction time and minimize dispersion while increasing system throughput. The bioanalytical utility of these systems was compared for quantifying of ACP activity in human serum standards.