LIQUID CHROMATOGRAPHY-FOURIER TRANSFORM-INFRARED SPECTROMETRIC DETERMINATION OF CHOLESTEROL IN ANIMAL GREASES

Stearic acid, cholesterol and cholesteryl palmitate have been separate d in less than 14 min by liquid chromatography on a column (3.9 mm i.d . x 150 mm) of Nova-Pack C-18 (5 mu m) using chloroform-acetonitrile ( 45 : 55) as mobile phase pumped at 0.5 ml min(-1): Fourier transform i nfrared (FTIR) spectrometry was employed for both, general detection a t 2868 or 2855 cm(-1) and selective detection at 3285 cm(-1) for stear ic acid and 3526 cm(-1) for cholesterol. In all cases a baseline estab lished at 3900 cm(-1), 9-point smoothing and chromatographic peak heig ht measurements were used. The method has been validated by applicatio n to the determination of cholesterol in animal greases and fish oils. Samples, previously saponified with KOH, were extracted with petroleu m ether, redissolved in chloroform and the final solution injected int o the chromatographic system. The percentage recoveries were 95-99% fo r samples spiked with cholesterol and 100-102% for samples spiked with cholesteryl palmitate. (C) 1997 Elsevier Science B.V.