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
Y1 - 2011
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
SN - 0039-9140
VL - 83
SP - 1233
EP - 1238
JO - Talanta
JF - Talanta
IS - 4
ER -