Vitamin D3: Preconcentration and Determination in Cereal Samples Using Ultrasonic‐Assisted Extraction and Microextraction Method

Abstract

This research is the first analytical method to isolate and determine cholecalciferol (vitamin D3) in cereal samples. Ultrasonic‐assisted extraction followed by dispersive liquid‐liquid microextraction as a fast, reliable, and highly sensitive method was employed for the preconcentration step. High‐performance liquid chromatography allowed an efficient and considerably faster analysis. Alcoholic KOH solution was employed for accomplishing the fast and easy release of vitamin D3 from the wheat flour and bread matrix. Effective factors in the microextraction process were investigated and optimized with response surface methodology based on a central composite design. Under the best conditions, the calibration curves showed high levels of linearity (R2 > 0.999) for vitamin D3 in the range of 2–500 ng/g. The relative standard deviation for the seven analyses was 6.2%. The relative recoveries of vitamin D3 in spiked wheat flour and bread samples were 87–98%. The limit of detection and limit of quantitation were 0.7 and 2.1 ng/g, respectively. The method compared favorably with other methods for vitamin D3 analysis of various foods.