Development of an FIA method with on-line microwave-assisted saponification of vitamin A to retinol and direct in-line spectrophotometric determination

Abstract

The development of an FIA method offering on-line saponification in a microwave oven of vitamin A to its retinol form with direct in-line ultraviolet detection is described. Comparison with a batch method indicates that the proposed method offers a more rapid, simple, methodology with improved yields in the saponification process. Optimized conditions are described for the FIA method, which gave an LOD of 0.3 mg l^–1 for vitamin A as retinol, a precision of between 1 and 3.8%s_r, a working calibration range up to 20 ppm and a sample throughput of less than 120 s.