Analysis of conjugated linoleic acids as 9-anthrylmethyl esters by reversed-phase high-performance liquid chromatography with fluorescence detection.
A simple and highly sensitive method for determining the fatty acid composition of food lipids containing conjugated linoleic acid (CLA) is described. The method is based on the separation of the 9-anthrylmethyl ester derivatives of saturated and unsaturated (conjugated and non-conjugated) fatty acids by reversed-phase high-performance liquid chromatography with fluorescence detection. Just like the other fatty acids, CLA reacts readily with 9-anthryldiazomethane at room temperature to produce 9-anthrylmethyl esters without isomerization and decomposition of the conjugated double bonds. Clear resolution of the individual fatty acids as their 9-anthrylmethyl esters is achieved on a highly efficient octadecylsilylated silica column (150- x 3-mm i.d., 3-microm particle size) using a stepwise gradient elution with methanol-water. The method is standardized with commercially available CLA isomers (cis-9, trans-11 and trans-10, cis-12-octadecadienoic acids, and their cis,cis and trans,trans isomers) and applied for determination of the fatty acid compositions of milk and sdairy products.
Nishimura
Kazuhiko
K
Graduate School of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan.
Suzuki
Toshiyuki
T
Momchilova
Svetlana
S
Miyashita
Kazuo
K
Katsura
Eiji
E
Itabashi
Yutaka
Y
D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003611:Dairy Products / Q000032:analysis; D004952:Esters; D044243:Linoleic Acids, Conjugated / Q000032:analysis* / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*
D004952:Esters; D044243:Linoleic Acids, Conjugated