Stable isotope labelling analysis of vulcanization accelerator 2-mercaptobenzothiazole in daily necessities

A pair of positively charged stable isotope labelled agents, 4-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-N,N,N-trimethylbenzenaminium iodide (d0-DDPTBA), and its deuterated counterpart, d3-DDPTBA were designed and synthesized. They were applied to the stable isotope labelling (SIL) analysis of 2-mercaptobenzothiazole with the aid of high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS).The method sensitivity was considerably enhanced due to the mass spectrometry (MS) sensitivity enhancement effect of positively charged DDPTBA, and the matrix effect was effectively minimized due to the SIL strategy. The limits of detection and quantification were 1.5 and 4.9 ng/kg, respectively. The recoveries were in the range of 95.2-96.8 %, and the matrix effect ranged from-2.2 % to-2.6 %. DDPTBA derivatives showed "DDPTBA-specific production ions", and the multiple reaction monitoring (MRM) parameters of DDPTBA-MBT can be applied in the analysis of other DDPTBA derivatives. It was applied to the sensitive MRM identification of other thiols in the absence of standard with four thiols identified.