A flow-through system for the determination of salicylate in blood

A flow-through system for the determination of salicylate in blood is described. It consists of a Clark-type oxygen probe with the enzyme salicylate hydroxylase chemically bound to polymer supports. This probe, when inserted into a flow-through cell in the presence of salicylate, oxygen and NAD(P)H, produced a current signal proportional to the concentration of salicylate. Salicylate was assayed in the range 10 mumol/l up to 200 mumol/l with a detection limit of 3 mumol/l. Salicylate analysis was optimized by selecting the appropriate pH, buffer, temperature, enzyme immobilization and NAD(P)H concentration. The accuracy of this method was evaluated by recovery studies on 15 sera. Analysis of salicylate in serum sample was performed by diluting samples thirty fold with phosphate buffer to fit the calibration graphs. The response time of the probe was 2 min and 6 min was the time to perform a single analysis. Results compared with the TDx procedure correlated well.