A liquid chromatographic method for the analysis of retinyl acetate in soybased infant formula using matrix solid phase dispersion

Retinyl acetate in soy based infant formula was extracted by matrix solid p hase dispersion (MSPD) and chromatographed by isocratic normal phase chroma tography on a Si 60 column with a mobile phase of 0.28% (v/v) isopropanol i n hexane. Detection was by fluorescence (Ex lambda=325, Em lambda=470). Flu orescence response was linear (r(2)=0.999) from 0.10 - 2.5 mu g/mL. Recover ies determined on a soy based infant formula zero control reference materia l (ZRM) containing added analyte at five levels averaged 94.79% (n=25) with CV's from 0.57-3.53%. The method expands the use of MSPD extraction to the analysis of retinyl acetate in soy based infant formulas.