A voltammetric method has been developed for the determination of N,N'-dinitrosopiperazine (DNPZ) in simulated gastric juice. The method is based on measuring the differential pulse polarographic peak produced in pH 3 Britton Robinson buffer. A well defined, diffusion-controlled cathodic wave was obtained at -0.77 V versus Ag/AgCl over the range 0.4-24 microg/ml with minimum detectability (S/N = 2) of 0.072 microg/ml (5 x 10(-7) M). The proposed method was successfully applied to study the possible in vivo production of the nitroso-derivatives of piperazine under the standard nitrosation reaction conditions recommended by WHO. The method has some distinct advantages over the reported GC methods.