title: Development of an impurity-profiling method for source identification of spilled benzene series compounds by gas chromatography with mass spectrometry: Toluene as a case study.
abstract: In this study, an impurity profiling method was established for the source identification of spilled benzene series compounds. Toluene was used as a case study to demonstrate the feasibility of this approach. Gas chromatography with mass spectrometry was applied for identification and quantification of the impurities including ethyl benzene, p-xylene, m-xylene, and o-xylene in toluene. Impurities in toluene were detected at very low levels by applying mass spectrometry in selected-ion monitoring mode. Eight authentic toluene samples collected from different manufacturers were analyzed by the developed gas chromatography with mass spectrometry method to construct the characteristic impurity profiling of toluene. Then, combined with scatter distribution, similarity analysis and t-test, a suite of diagnostic ratios based on the impurity distribution was used for the differentiation of toluene from different sources. Results indicated that scatter distribution method can discriminate the original toluene samples from different manufacturers. Similarity calculation and t-test methods can identify effectively the weathered toluene samples. The proposed impurity profiling method was useful for discrimination between toluene samples from different sources. Statistical analysis of these impurity profiles demonstrated the potential to investigate whether two questioned spilled toluene samples encountered in forensic casework are from the same source.
authors.affiliation: First Institute of Oceanography, State Oceanic Administration, Research Center for Marine Ecology, Qingdao, P. R. China.|Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, P. R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Han
authors.affiliation: First Institute of Oceanography, State Oceanic Administration, Research Center for Marine Ecology, Qingdao, P. R. China.
authors.forename: Junhui
authors.initials: J
authors.lastname: Chen
authors.affiliation: First Institute of Oceanography, State Oceanic Administration, Research Center for Marine Ecology, Qingdao, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Zheng
authors.affiliation: First Institute of Oceanography, State Oceanic Administration, Research Center for Marine Ecology, Qingdao, P. R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhou
authors.affiliation: First Institute of Oceanography, State Oceanic Administration, Research Center for Marine Ecology, Qingdao, P. R. China.
authors.forename: Jingxi
authors.initials: J
authors.lastname: Li
authors.affiliation: First Institute of Oceanography, State Oceanic Administration, Research Center for Marine Ecology, Qingdao, P. R. China.
authors.forename: Xiaoru
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, P. R. China.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Wang
keywords: Benzene series; Diagnostic ratio; Identification; Impurity profiling; Toluene