Interference with the kinetic determination of acid phosphatase.

This study advocates cautious use of the kinetic determination method for acid phosphatase with alpha-naphthylphosphate as substrate and a diazonium salt for colour development. The occurrence of considerable blank rates due to the spontaneous hydrolysis of the substrate was noticed. Of the diazonium salts which were tested as alternatives for Fast Red TR, diazotised p-nitroaniline seemed to be useful. Also the interaction between plasma components and diazonium salts may influence the results of the determination. In this respect a number of possible interfering compounds was investigated and from these a structural element which may lead to side reactions was deduced.