Innovative Approaches for Estimating the Levels of Tobacco-Specific Nitrosamines in Cured Tobacco Samples

• Published in: Chemical research in toxicology 2018-09, Vol.31 (9), p.964-973
• Main Authors: Kaiser, Samuel, Soares, Frederico L. F, Ardila, Jorge A, Marcelo, Marcelo C. A, Dias, Jailson C, Porte, Liliane M. F, Gonçalves, Carlos, Pontes, Oscar F. S, Sabin, Guilherme P
• Format: Article
• Language: English
• Subjects: Carcinogens - analysis; Flow Injection Analysis - methods; Least-Squares Analysis; Mass Spectrometry - methods; Nicotiana - chemistry; Nitrosamines - analysis
• ISSN: 0893-228X; 1520-5010
• DOI: 10.1021/acs.chemrestox.8b00154

Tobacco-specific nitrosamines (TSNAs), mainly the 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), are known carcinogens. Part of the NNK found in smoke is provided from matrix-bound NNK, and its determination is extremely relevant. However, the reference extraction procedure of matrix-bound NNK is time-consuming and labor-intensive and has a limited analytical capacity. Three different methodologies were proposed to predict matrix-bound NNK: simple linear regression (LR) with soluble NNK; multiple linear regression (MLR) considering soluble NNK and characteristic parameters of the samples; and orthogonal partial least-squares (O-PLS) regression using high-throughput screening by flow injection analysis coupled to high-resolution mass spectrometry (HTS-FIA-HRMS) data. Simple linear regression showed a high influence of matrix and leaf origin. Although an existing linearity trend has been observed (R 2 = 0.62) for the global model, higher correlation values were achieved for matrix and country segregation models. Multiple linear regression predicted matrix-bound NNK with more satisfactory efficiency than simple linear regression models. The coefficients of determination were 0.87 and 0.94 for flue-cured Virginia and air-cured Burley, respectively. However, this method has a limited application, since previous information about the sample is required. The proposed method based on HTS-FIA-HRMS and O-PLS has shown the most suitable performance in the prediction of matrix-bound NNK, with errors comparable to the reference method, and a higher throughput. In addition, this approach allows to determine other soluble nitrosamines, namely N′-nitrosoanatabine, N′-nitrosoanabasine, and N-nitrosonornicotine, with relative percentage errors between 5.25 and 11.98%. Therefore, the third approach is the best method for a large number of cured tobacco for accuracy in determination of TSNAs.