Benzo[a]pyrene in tobacco products by ultra-pressure liquid chromatography with fluorescence detection using its deuterated analog as an internal standard.
Benzo[a]pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) classified by the International Agency for Research on Cancer (IARC) as a group 1 carcinogen. BaP is formed as a product of incomplete combustion and is found in tobacco smoke as well as tobacco, particularly dark-fire cured. There is much interest in BaP in tobacco products and its testing is required by regulatory bodies (e.g. Health Canada and the United States Food and Drug Administration) as well as manufacturers (e.g. Swedish Match’s Gothiatek standard).
The objective of this study was to develop and validate an analytical method for BaP in various tobacco products as an improved alternative to an in-house GC-MS method, which required extensive sample clean-up and a long analysis time.
BaP was extracted from tobacco with methanol; shaken mechanically then centrifuged. An aliquot of supernatant was concentrated by a factor of 20 and filtered. Analysis was performed by ultra-pressure liquid chromatography (UPLC) with fluorescence detection using a Zorbax Eclipse PAH analytical column with an isocratic mobile phase consisting of water-acetonitrile. Quantitation was performed by the internal standard technique using deuterated d12-BaP. A range of individual leaf grades, reference and commercial products were evaluated by this method. CRP2, CRP3 and 3R4F gave results of 52.4, 39.5, 8.16 ng/g, respectively, which compared favorably to results obtained by the in-house GC-MS method. The limit of quantitation for BaP by this method is 0.1 ng/mL, equivalent to 0.1 ng/g.
The method was validated with acceptable linearity, accuracy, precision and selectivity to produce a robust method that utilized a simple extraction and shorter analysis time.