Analysis of four volatile nitroso-amines, four alkaloids, 18 polycyclic aromatic hydrocarbons in oral tobacco products based on simultaneous extraction technique and GC-MS/MS detection
Many kinds of harmful or potentially harmful components (HPHCs) exist in oral tobacco products. Usually, each kind of chemical needs a specific analytical method, which will cause high cost and low throughput. Therefore, the objective of this study was to develop a high-throughput simultaneous extraction scheme with two phase solution (5 % NaOH water solution: CH2Cl2) for 18 polycyclic aromatic hydrocarbons (PAHs), four volatile nitroso-amines (VANs), nicotine and three minor alkaloids. With reference to the 18 PAHs and four VANs of ng/g level, the solid phase extraction step with a silica column was designed for further purification. After optimization, the three classes of targets were determined by two GC-MS/MS equipped with an EI and CI source respectively. The developed analytical method was systematically validated. The limits of quantification for the 18 PAHs, four VANs, three minor alkaloids and nicotine were 0.2~1.2 ng/g, 0.2~0.4 ng/g, 0.6~1.0 µg/g, 10.2 µg/g, respectively. The inter-day precisions and the intra-day precisions for all of the targets were all controlled less than 8.5 %, 11.2 %. Using CRP1, CRP2, one chewing gum, and one dissolvable product as substrates to prepare calibration lines, the ratios of the slope of the calibration line by matrix preparation to the slope of the corresponding calibration lines by solvent preparation were in the range of 89 %~111 % for all the targets. With the low, medium, high spiked levels, the measured recovery rates for all the targets were all between 83 % and 110 %. Therefore, the developed method was proven to be of good repeatability, high sensitivity and accuracy. The developed method was then used to assay 18 oral tobacco products.