Background: MBT, a rubber accelerator, was popularly used in rubber manufacturing.
However, the experts from the International Agency for Research on Cancer suggested that MBT
was listed in Group 2A carcinogenic material.
Methods: Therefore, we developed a quantification method based on LC-QqQ-MS/MS, using isotopic
iodoacetamide and 13C2, D2-iodoacetamide to react with the thiol group on MBT to generate the
iodoacetamide-modified MBT as a standard for a calibration curve and the 13C2, D2-iodoacetamidemodified
MBT analog as an internal standard.
Results: Using LC-QqQ-MS/MS, we explored a Multiple Reaction Monitoring (MRM) MS detection
mode by detecting m/z of precursor and product ions of MBT, and this method was validated using
linear range, LOD, LOQ, intra-day, inter-day, and average recoveries. This validated method was
successfully applied to a waste tire as a real sample.
Conclusion: By a complete synthesis with isotopic iodoacetamide alkylation, MBT could be modified
with iodoacetamide and 13C2, D2-iodoacetamide with high yields. Furthermore, in MS detection,
the signal enhancement could be observed clearly after alkylation. Therefore, this modification of
MBT with isotopic iodoacetamide vastly improved the detection of MBT by mass spectrometry.