The liquid chromatographic analysis of vitamin K1 in soy based infant formula using matrix solid phase dispersion

A liquid chromatographic method is described for vitamin K-1 in soy based infant formula. The vitamins are extracted from infant formula by matrix solid phase dispersion (MSPD) and quantitated by reversed phase chromatography with fluorescence detection. Vitamin K-1 is converted to the fluorescent hydroquinone with a post column zinc reductive reactor. The limit of detection is 12 pg and the limit of quantitation is 38 pg on- column. Linear response ranged from 0.70 - 11.0 ng/mL (r(2) = 0.998). Recoveries were determined on an analyte-fortified blank material for soy based infant formula and averaged 92.5% (n = 25) for vitamin K-1. The method provides a rapid, specific, and easily controlled assay for the analysis of vitamin K-1 in fortified soy based infant formula.