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Quantitative determination of conjugated linoleic acid isomers in beef fat
Author(s) -
Fritsche Jan,
Fritsche Sonja,
Solomon M. B.,
Mossoba M. M.,
Yurawecz M. P.,
Morehouse K.,
Ku Y.
Publication year - 2000
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/1438-9312(200011)102:11<667::aid-ejlt667>3.0.co;2-n
Subject(s) - conjugated linoleic acid , chemistry , high performance liquid chromatography , chromatography , linoleic acid , detection limit , gas chromatography , fatty acid , organic chemistry
The amounts of 14 conjugated linoleic acid (CLA) isomers (t12t14, t11t13, t10t12, t9t11, t8t10, t7t9, t6t8; 12,14 c/t, t11c13, c11t13, t10c12, 9,11 c/t, t8c10, t7c9‐18:2) in 20 beef samples were determined by triple‐column silver‐ion high‐performance liquid chromatography (Ag + ‐HPLC). Quantitation was performed using an external CLA reference standard consisting of cis 9, trans 11‐18:2, trans 9, trans 11‐18:2 and cis 9, cis 11‐18: 2. Linearity was checked as being r > 0.9999 between 0.02 × 10 ‐3 to 2 mg/ml. The determination limit (5‐fold signal/noise ratio) of the CLA reference was estimated to be 0.25, 0.50, 1.0 ng/injection for the cis/trans , trans , trans and cis , cis isomers, respectively. As expected, cis 9, trans 11‐18:2 was the predominant isomer (1.95 ± 0.54 mg/g fat) in beef, followed by trans 7, cis 9‐18:2 (0.19 ± 0.04 mg/g fat); cis , cis isomers were below the determination limit in most beef samples. Total CLA amounts determined by Ag + ‐HPLC were compared to total CLAs determined by gas chromatography (GC, 100 m CPSil TM 88 column). The amounts obtained by GC were generally higher than those determined by Ag + ‐HPLC due to co‐eluting compounds.