ABSTRACT
Physicochemical methods for determining vitamins in foods began with colorimetric methods, which required open-column chromatography or thin-layer chromatography to isolate the vitamins from interfering substances. In the 1960s, gas chromatography (GC) became the dominant technique for determining vitamins D and E. The columns used at that time were of the packed type and lacked the sophistication of modern capillary columns. Cleanup of sample extracts by open-column or thinlayer chromatography was still necessary, as was derivatization to increase the vitamins’ thermal stability and volatility. The subsequent development of fused-silica open tubular capillary columns has revived the interest in GC. The introduction of high-performance liquid chromatography (HPLC) in the early 1970s led to its becoming the technique of choice for the determination of fat-soluble vitamins and carotenoids. Other modern separation techniques of potential application are supercritical fluid chromatography, capillary electrophoresis, and continuousflow analysis.
