Trace Analysis of Mutagenic Heterocyclic Aromatic Amines in Cigarette Smoke Condensate and its Base Fractions via Silylation-GC-MS

Among the more than 5000 chemicals reported in cigarette smoke condensate (CSC), heterocyclic aromatic amines (HAAs) are considered to be a contributor to observed biological activity. HAAs are non-volatile and are reported at ppb levels in CSC. A new method for HAA analysis at the trace level is reported here. N, O-Bis(trimethylsilyl) trifluoroacetamide (BSTFA) containing 1% trimethylchlorosilane was employed to derivatize amino groups by heating the reagent containing a sample of CSC at 80 °C for 30 min followed by analysis employing gas chromatography-mass spectroscopy (GC-MS) in the selected-ion-monitoring (SIM) mode. This derivatization method afforded symmetrical peak shapes on a ZB-50 stationary phase and achieved instrumental limits of quantification (LOQ) at 10:1 S/N from -1 ng/mL for AαC to120 ng/mL for Glu-P-1. The chemical identity of each derivative was confirmed by comparison of retention time and mass spectra of standards. The latter were characterized by the following ions: M·+ or [M-1]+, [M-15]+, and m/z 73 (i.e., trimethylsilyl). CSC and its base sub-fractions were studied using the GC-MS method. Ten HAAs were screened and five were quantified in cigarette smoke condensate, while 2-5 HAAs were quantified in each of three base sub-fractions. Values obtained with the new procedure agree well with values reported in the literature and with results obtained from a commercial laboratory via a different analytical method. The potential contribution of each HAA to the overall mutagenic activity observed for CSC and its base fractions is discussed. When considered together, HAAs account for only a small portion (-7.8%) of the observed mutagenicity of the CSC.