FLOW-THROUGH BIOSENSOR FOR SEQUENTIAL DETERMINATION OF TOTAL AND PROSTATIC ACID-PHOSPHATASE-ACTIVITY

Two continuous methods based on the use of a conventional flow-injecti on system and a flow-through sensor for the sequential determination o f total and prostatic acid phosphatase activity are reported. The bioc hemical basis of both methods is the hydrolysis of p-nitrophenyl-phosp hate catalysed by the analyte and photometric monitoring of the reacti on product (p-nitrophenol) at 405 nm. The enhancement of sensitivity a chieved when this species is retained on the support packed in the flo w cell makes the method suitable for the determination of the analyte activity in serum samples after 1:5 dilution. The excellent agreement of the results obtained by the proposed and a conventional method and also the recoveries obtained prove the usefulness of the proposed bios ensor.