Differential Pulse Polarographic Determination of Some Carcinogenic Nitrosamines

Abstract

The pulse polarographic behavior of N-nitrosopyrrolidine and two of its derivatives, N-nitrosoproline and N-nitroso-4-hydroxyproline, has been investigated in buffered solutions over a range of pH. The effects of temperature, mercury pressure, modulation amplitude, surfactant concentration, and solvent and supporting electrolyte have been studied. The reduction process is complicated and pH-dependent. In acid solutions, N-nitrosopyrrolidine and its derivatives give one irreversible reduction wave, while for pH greater than 6, only N-nitrosopyrrolidine itself is reduced. The reduction waves of N-nitrosoproline and N-nitroso-4-hydroxyproline at pH below 5 are diffusion-controlled in dc and normal pulse polarographic modes. In aqueous medium, N-nitrosopyrrolidine, N-nitrosoproline, and N-nitroso-4-hydroxyproline have been detected quantitatively at the 10-7 M level by differential pulse polarography with adequate precision and accuracy. The importance of examining electrochemical behavior to aid in selecting conditions for analysis is discussed. © 1975, American Chemical Society. All rights reserved.