A Fast and Simple Method for Determination of Vitamin E in Infant Formula by Dispersive Liquid-Liquid Microextraction Combined with HPLC-UV

Abstract

Developing a simple and fast method for quantification of vitamins in complex matrixes is one of the important issues in quality control of foods such as milk. In this study, after introducing a new method for quantification of vitamin E in infant formula, its content was compared to the label claims. In this study, dispersive liquid-liquid microextraction (DLLME) procedure with acetonitrile and chloroform as dispersive and extraction solvents, respectively, was used for isolation and clean-up of vitamin E from infant formula samples without the need for saponification. Then, reversed-phase high-performance liquid chromatography (RP-HPLC) composed of a C18 column as stationary phase and the mixture of acetonitrile, methanol, and water (91:8:1%) as mobile phase using a standard addition method was employed for quantification of vitamin E (α-tocopheryl acetate) with UV detection at 296 nm. After method validation under the optimum conditions, the method provided a linear range with a determination coefficient (R2) of 0.99 and acceptable accuracy and precision. Results showed that the developed method is an appropriate method for quality control of infant formulas. The advantage of DLLME compared with saponification process and liquid-liquid extraction is the decrease of organic solvent consumption and proposing of a simple and fast method for analysis of vitamin E in infant formula. Application of the developed method for analysis of vitamin E in infant formulas on the market showed there was a considerable difference between labeled and obtained content in most of the samples.