مقالات محیط زیست

Combined cluster and discriminant analysis: An efficient chemometric approach in diesel fuel characterization
Forensic Science International (2017)
Márton Novák, Dóra Palya, Zsolt Bodai, Zoltán Nyiri, Norbert Magyar, József Kovács, Zsuzsanna Eke
Combined cluster and discriminant analysis (CCDA) as a chemometric tool in compound specific isotope analysis of diesel fuels was studied. The stable carbon isotope ratios (δ13C) of n-alkanes in diesel fuel can be used to characterize or differentiate diesels originating from different sources. We investigated 25 diesel fuel samples representing 20 different brands. The samples were collected from 25 different service stations in 11 European countries over a 2 year period. The n-alkane fraction of diesel fuels was separated using solid-state urea clathrate formation combined with silica gel fractionation. The stable carbon isotope ratios of C10–C24 n-alkanes were measured with gas chromatography–isotope ratio mass spectrometry (GC–IRMS) using perdeuterated n-alkanes as internal standards. Beside the 25 samples one additional diesel fuel was prepared and measured three times to get totally homogenous samples in order to test the performance of our analytical and statistical routine. Stable isotope ratio data were evaluated with hierarchical cluster analysis (HCA), principal component analysis (PCA) and CCDA. CCDA combines two multivariate data analysis methods hierarchical cluster analysis with linear discriminant analysis (LDA). The main idea behind CCDA is to compare the goodness of preconceived (based on the sample origins) and random groupings. In CCDA all the samples were compared pairwise. The results for the parallel sample preparations showed that the analytical procedure does not have any significant effect on the δ13C values of n-alkanes. The three parallels proved to be totally homogenous with CCDA. HCA and PCA can be useful tools when the examining of the relationship among several samples is in question. However, these two techniques cannot be always decisive on the origin of similar samples. The initial hypothesis that all diesel fuel samples are considered chemically unique was verified by CCDA. The main advantage of CCDA is that it gives an objective index number about the level of similarity among the investigated samples. Thus the application of CCDA supplemented by the traditionally used multivariate methods greatly improves the efficiency of statistical analysis in the CSIA of diesel fuel samples.
Environmental assessment of freshwater ecosystems of the Sava River watershed and Cerkniško Lake, Slovenia, using the bioindicator species Fontinalis antipyretica : insights from stable isotopes and selected elements.
Isotopes in Environmental and Health Studies (2016)
Compound-Specific Stable Isotope Fractionation of Pesticides and Pharmaceuticals in a Mesoscale Aquifer Model, Environ
Sci. Technol (2016)
Application of stable isotope tools for evaluating natural and stimulated biodegradation of organic pollutants in field studies
Curr Opin Biotechnol. (2016)

اطلاعات تماس

اراک - میدان بسیج - بلوار کربلا - دانشگاه اراک - آزمایشگاه مرکزی- مرکز تحقیقات ایزوتوپهای پایدار

Email: a-sirl@araku.ac.ir

تلفن : ۳۲۶۲۲۸۲۲ ۰۸۶ - ۳۲۶۲۲۸۲۰ ۰۸۶

امکانات

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