Premium
Analysis of CLA Isomer Distribution in Nutritional Supplements by Single Column Silver‐Ion HPLC
Author(s) -
Cossignani L.,
Giua L.,
Lombardi G.,
Simonetti M. S.,
Damiani P.,
Blasi F.
Publication year - 2013
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-012-2176-x
Subject(s) - chemistry , conjugated linoleic acid , high performance liquid chromatography , chromatography , methanol , resolution (logic) , composition (language) , fatty acid , gas chromatography , linoleic acid , organic chemistry , linguistics , philosophy , artificial intelligence , computer science
Nutritional supplements containing conjugated linoleic acid (CLA) isomers, widely used to improve body composition and inhibit fat storage, should be thoroughly analyzed, as CLA effects are isomer specific. In this research, an improvement of silver‐ion high performance liquid chromatography (Ag + ‐HPLC) was obtained by using a single‐column instead of the most commonly used multi‐columns. To develop the procedure, a standard CLA mixture has been derivatized with different chain length alcohols (from methanol to hexanol). Hexyl CLA showed better separation between CLA isomer pairs, in particular the resolution of the t 10 ,c 12: c 9, t 11 pair increased from 0.3 (methyl esters) to 0.8 (hexyl esters). Therefore, the CLA isomer composition of some commercial CLA products was determined by Ag + ‐HPLC analysis of hexyl esters. The main isomers in all supplements turned out to be c 9, t 11‐CLA and t 10, c 12‐CLA, the most anti‐adipogenic isomer. t 8, c 10‐ and c 11, t 13‐CLA were not detected. The nutritional supplements were also analyzed by high resolution gas chromatography of methyl esters to evaluate the fatty acid % composition and total CLA % content. The total CLA ranged from 79.4 to 94.4 %, and the t , t isomer from 1.4 to 7.3 %.