[The determination of vitamin D in fortified milk and other foods by high performance liquid chromatography (HPLC)].
An HPLC procedure for determination of vitamin D(VD) in fortified milk and food has been developed. The samples were saponified by adding KOH, ethanol and vitamin C at 75 degrees C for 30 min. The digest was extracted with hexane in multistep manner. The extract was washed with 5% KOH, distilled water and 55% ethanol, and evaporated under reduced pressure at 50 degrees C. The residue was dissolved in hexane, transferred to a coentrifuge tube, evaporated under N2 and then dissolved in 200 microL mobile phase. The latter was injected into a silica column (10 microm, 30 cm x 4 mm) for cleanup, eluted with mixture of cyclohexane-hexane containing 0.8% isopropanol and detected at UV 254nm. VD fraction was collected according to the retention time of standard, evaporized under N2, redissolved in 100 microL MeOH, and separated on a C18 column (10 microm, 30 cm x 4 mm) with MeOH/H2O (98:2) as eluent. VD2 and VD3 were eluted as a mixture under the conditions. Recoveries of the method were 94.8% to 99.7%. The average CV (n = 5) for within and between day measurements were 1.6% and 2.1% respectively. This method was already used to determine the content of vitamin D in milk powder, pulvis elementi compound, mixed proteins, dried meat floss, humanized milk power, children health drink, milk wheat powder and fortified milk. The method is simple, rapid and accurate.
Wu
H
H
Institute of Hygiene and Environmental Medicine, Academy of Military Medical Sciences, Tianjin, 300050.
Cheng
H
H
Tian
J
J
Wang
X
X
D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005504:Food Analysis; D006801:Humans; D008892:Milk / Q000737:chemistry*; D014807:Vitamin D / Q000032:analysis*
D014807:Vitamin D