Continuous-flow automated HPLC analysis of fat-soluble vitamins in tablets

A prototype automated system involving continuous-flow analysis and high performance liquid chromatography (CFA/HPLC) has been developed for the analysis of fat-soluble vitamins in individual pharmaceutical tablets. The novel features are the front-end coupling of CFA to HPLC, injection of hexane solutions on reversed phase columns, separation/quantitation of vitamins A, D2 and E within single chromatographic runs for a wide variety of tablets, and a dynamic range sufficient to accommodate the 1000-fold higher levels of vitamins a and E over D2 in the same tablets. The analysis rate is 10 samples per hour, the precision better than 6% for all three vitamins, and the recovery is 70-90% of that obtained by the standard AOAC method. Although the system is a prototype, it already greatly outperforms current manual analyses which are time consuming, tedious, and demanding in terms of the level of skill and experience of the experimenter. Included in this work are some retention comparisons of commercial columns.