Separation of N-nitrosamines by micellar electrokinetic chromatography

Abstract

A simple and rapid micellar electrokinetic chromatography (MEKC) method was developed for separation of three selected N-Nitrosamines namely N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA). The effects of composition of the buffer and its pH, concentration of surfactants on the separation and migration times of nitrosamines were investigated. The instrumental variables affecting sensitivity and resolution such as power supply and injection mode were carefully optimized. The best separation was achieved using 40 mM sodium dodecyl sulfate (SDS) as a surfactant in 10 mM phosphate buffer (pH 8.0) at a temperature of 25 ºC, applied voltage of 29 kV, wavelength of 230 nm and electrokinetic injection of 9 s at 5 kV within 10 min analysis time. Excellent linearity was obtained in the concentration range of 2 to 100 μg/mL with coefficients of determination, r2 ≥ 0.979. This method showed good reproducibility with relative standard deviation (RSDs) value ranging from 2.46% to 6.61%. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.16 to 0.43 μg/mL and 0.54 to 1.44 μg/mL respectively.