Numerical methods for comparing fresh and weathered oils by their FTIR spectra Li, Jianfeng en_US Hibbert, D. Brynn en_US Fuller, S en_US 2021-11-25T13:06:00Z 2021-11-25T13:06:00Z 2007 en_US
dc.description.abstract Four comparison statistics(`similarity indices`) for the identification of the source of a petroleum oil spill based on the ASTM standard test method D3414 were investigated. Namely, ( 1) first difference correlation coefficient squared and ( 2) correlation coefficient squared, ( 3) first difference Euclidean cosine squared and ( 4) Euclidean cosine squared. For numerical comparison, an FTIR spectrum is divided into three regions, described as: fingerprint (900-700 cm(-1)), generic (1350-900 cm(-1)) and supplementary (1770-1685 cm(-1)), which are the same as the three major regions recommended by the ASTM standard. For fresh oil samples, each similarity index was able to distinguish between replicate independent spectra of the same sample and between different samples. In general, the two first difference-based indices worked better than their parent indices. To provide samples to reveal relationships between weathered and fresh oils, a simple artificial weathering procedure was carried out. Euclidean cosine and correlation coefficients both worked well to maintain identification of a match in the fingerprint region and the two first difference indices were better in the generic region. Receiver operating characteristic curves ( true positive rate versus false positive rate) for decisions on matching using the fingerprint region showed two samples could be matched when the difference in weathering time was up to 7 days. Beyond this time the true positive rate falls and samples cannot be reliably matched. However, artificial weathering of a fresh source sample can aid the matching of a weathered sample to its real source from a pool of very similar candidates. en_US
dc.identifier.issn 0003-2654 en_US
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri en_US
dc.source Legacy MARC en_US
dc.title Numerical methods for comparing fresh and weathered oils by their FTIR spectra en_US
dc.type Journal Article en
dcterms.accessRights open access
dspace.entity.type Publication en_US
unsw.description.publisherStatement Reproduced by permission of The Royal Society of Chemistry (RSC). en_US
unsw.identifier.doiPublisher en_US
unsw.relation.faculty Science
unsw.relation.ispartofissue 8 en_US
unsw.relation.ispartofjournal Analyst en_US
unsw.relation.ispartofpagefrompageto 792-800 en_US
unsw.relation.ispartofvolume 132 en_US
unsw.relation.originalPublicationAffiliation Li, Jianfeng, Chemistry, Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Hibbert, D. Brynn, Chemistry, Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Fuller, S en_US School of Chemistry *
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