Differential Pulse Polarographic Determination of Carcinogenic, 4-(N-Nitrosobutylamino)-1-butanol

Abstract

The pulse polarographic behavior of a carcinogenic nitrosamine, 4-(N-nitrosobutylamino)1-butanol (NBBN) in aqueous solutions has been studied. The effects of temperature, mercury pressure, modulation amplitude, and pH have been investigated. The reduction process is complicated and pH-dependent. In acid solution with pH below 4, the slope of potentialpH curve is -123 mV/pH, also the slope being -86 mV/pH in the pH range between 4.5 and 7 (Fig.1). From the dependence of mercury pressure, h_corr on the current, i by normal pulse (NP) mode, the value of log i-log h_corr plot remains near O.68, being diffusion-controlled. In addition, the slope of i-t curve by the first drop polarograph was ca.0.20 the same as the theoretical value of O.192. The relative temperature coefficients of the limiting current at 20°C lie in the range 1 to 2%/°C, corresponding to the diffusion-controlled current. The differential pulse polarographic peak height is proportional to the concentration of NBBN between 2.5 x 10^-7, and 2.75 X 10^-6mol⋅dm^-3. The detection limit for NBBN under the same conditions shown in Fig.5 was 8.64 X 10^-8mol⋅dm^-3 at ΔE=-50 mV. In the artificial sample of human urine added NBBN, the nitrosamine could not be determined directly because of the interference of protein, bacilli, nitrite and so on. Therefore, it is necessary to do cleanup of the sample by use of freeze-dry and/or column chromatogrphic method.