TY - JOUR

T1 - Identification of the geometrical isomers of α-linolenic acid using gas chromatography/mass spectrometry with a binary decision tree

AU - Hejazi, Leila

AU - Hibbert, David Brynn

AU - Ebrahimi, Diako

PY - 2011/1/1

Y1 - 2011/1/1

N2 - Gas chromatography, using a highly polar column, low energy (30 eV) electron ionization mass spectrometry and multivariate curve resolution, are combined to obtain the mass spectra of all eight geometrical isomers of α-linolenic acid. A step by step Student's t-test is performed on the m/z 50-294 to identify the m/z by which the geometries of the double bonds could be discriminated. The most intense peak discriminates between cis (m/z 79) and trans (m/z 95) at the central (carbon 12) position. The configuration at carbon 15 is then distinguished by m/z 68 and 236, and finally the geometry at carbon 9 is determined by m/z 93, 173, 191 and 236. A three-question binary tree is developed based on the normalized intensities of these ions by which the identity of any given isomer of α-linolenic is accurately determined. Application of Bayes theorem to data from independent samples shows that the complete configuration is determined correctly with a minimum probability of 87%.

AB - Gas chromatography, using a highly polar column, low energy (30 eV) electron ionization mass spectrometry and multivariate curve resolution, are combined to obtain the mass spectra of all eight geometrical isomers of α-linolenic acid. A step by step Student's t-test is performed on the m/z 50-294 to identify the m/z by which the geometries of the double bonds could be discriminated. The most intense peak discriminates between cis (m/z 79) and trans (m/z 95) at the central (carbon 12) position. The configuration at carbon 15 is then distinguished by m/z 68 and 236, and finally the geometry at carbon 9 is determined by m/z 93, 173, 191 and 236. A three-question binary tree is developed based on the normalized intensities of these ions by which the identity of any given isomer of α-linolenic is accurately determined. Application of Bayes theorem to data from independent samples shows that the complete configuration is determined correctly with a minimum probability of 87%.

KW - Bayes theorem

KW - Fatty acid methyl ester

KW - GC/MS

KW - Geometrical isomers

KW - Structure elucidation

KW - Unsaturated fatty acid

UR - http://www.scopus.com/inward/record.url?scp=79251594209&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79251594209&partnerID=8YFLogxK

U2 - 10.1016/j.talanta.2010.10.017

DO - 10.1016/j.talanta.2010.10.017

M3 - Article

C2 - 21215858

AN - SCOPUS:79251594209

VL - 83

SP - 1233

EP - 1238

JO - Talanta

JF - Talanta

SN - 0039-9140

IS - 4

ER -