Simplified method for the determination of N-nitrosamines in rubber vulcanizates

A simplified method for the trace determination of N-nitrosamines in carbon black-loaded rubber compounds is described. The extraction of volatile nitrosamines is accomplished by thermal desorption rather than the traditional solvent extraction procedure. The analytes are trapped on Thermosorb/N sorbent and subsequently analyzed by gas chromatography with thermal energy analyzer detection (GC/TEA). Conditions that provide full extraction of nitrosamines from actual rubber compounds were determined to be 30 min at 150 °C in vessels dynamically purged with N2. Method precision was found to be 10% for NDMA at 71 ng/g and 7.3% for NMOR at 248 ng/g. Recoveries for the seven common N-nitrosamines ranged from 94 to 117%. Limits of detection in the rubber matrix are 6.3–13 ng/g. The technique is found to offer improved recovery of lower molecular weight nitrosamines and it is shown to be simpler and faster than previous techniques.