Determination of vitamin A in cereal flours,vegetable oil and sugar.Determination of vitamin A in flours, vegetable
oil and sugar were carried out using the same procedure as described by Ashoor and Knox,1987 for both SAGL and University of Ibadan (CMRL, UI) samples. Five grams of samples were saponified with 5.7 N alcoholic KOH for 45 min
and then extracted with diethyl- and petroleum ether. The vitamin A as retinol is analysed by reverse phase HPLC at 327 nm using a UV detector. The standard used was dry vitamin A Palmitate (250 CWS/F) from Chempure for SAGL (http://www. chempure.co.za/). With each set of samples, an in-house quality control sample was included; the sample was an AACC VMP proficiency sample. For sugar and cereal flour samples, a 100 g sample was dissolved in 100 ml water and a subsample of 6.25 g was analyzed according to the previous methodology summary