A simple photokinetic method for the determination of nitroprusside in biological and pharmaceutical samples.

A simple method has been developed for the determination of nitroprusside in human serum and pharmaceutical preparations. The new method is based on the strong inhibitory effect of nitroprusside on the photochemical reduction of phloxin by ethylenediaminetetra-acetic acid. The rate measurements are accomplished very simply by measuring the time needed for the absorbance to be reduced to 1/10th of its initial value. Optimal conditions for the determination of nitroprusside at concentrations of 15-200 ng ml-1 are described.