Determination of N-nitrosamines in rubber products by solid phase extraction purification and ultra high performance liquid chromatography-tandem mass spectrometry

Abstract

A method using C18 solid phase extraction (SPE) for purification and ultra high performance liquid chromatography (UHPLC) coupled with electrospray ionization tandem mass spectrometry (ESI-MS/MS) for detection was developed to simultaneously determine 13 N-nitrosamines in rubber products. The analytes were extracted with methanol (60 degrees C, 30 min) with the aid of ultrasonic technique and then purified by a C18 SPE cartridge. The analytes were separated on a C18 chromatographic column and qualitatively and quantitatively detected by a mass spectrometer with positive ESI at multiple reaction monitoring (MRM) mode. The operating parameters for UHPLC separation and ESI-MS/MS detection were also optimized. Under optimum operating conditions, the relative standard deviations (RSDs, n = 7) were less than 10% at spiked level of 50 microg/kg for all analytes except N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) which were spiked at 500 microg/kg. The recoveries spiked in real from 70.7% to 117.0%. The limits of detection (LODs, 10 times of standard deviation) were in the range of 0.5 - 500 microg/kg. The method has been successfully applied to the simultaneous determination of the 13 N-nitrosamines in rubber products.