A rapid and sensitive method to measure the levels of twelve heterocyclic aromatic amines (HAAs) in mainstream tobacco smoke condensate has been developed. Mainstream smoke collected onto a glass fibre filter pad is extracted into 0.1M of hydrochloric acid (HCl), with isotope-labelled HAAs added as internal standard (IS). Sample matrix effects are reduced by solid-phase extraction (SPE) using a mixed mode (non-polar and cation exchange) polymeric sorbent. The purified extract is analyzed using an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) system operating in selected reaction monitoring (SRM) mode. The combination of the SPE and UPLC system provided sensitivity improvements compared to other published LC-MS/MS methods. Most of target HAAs can be analyzed at levels below 0.5 ng/cig.

For the HAAs investigated, average recoveries obtained from spiked reference cigarette smoke matrices ranged from 100 to 118% with relative standard deviations (RSDs) under 14.5%. The precision of the method was evaluated by analyzing HAAs in the mainstream smoke of Kentucky Reference cigarette 3R4F smoked under two smoking regimens: ISO (35mL puff volume, 60 second puff frequency, no vent blocking) and Health Canada Intense (55mL puff volume, 30 second puff frequency, 100% vent block). Seven of twelve target HAAs including IQ, norharman, harman, Trp-P-1, AaC, Trp-P-2, and MeAaC, were detected in mainstream smoke of 3R4F cigarettes. The RSD values obtained were below 10.1% for norharman, harman, AaC, MeAaC, and ranged from 9.8 to 20.0% for IQ, Trp-P-1, Trp-P-2. The levels of Glu-P-1, MeIQ, Glu-P-2, MeIQx, and PhIP in mainstream smoke of 3R4F cigarettes smoked under both smoking conditions were all below the method detection limit.

Yields of HAA’s determined by this method are in agreement with those obtained using a validated GC/MS method and the published LC-MS/MS method.