STUDIES ON FOOD ADDITIVES (ERYTHORBIC ACID) ABSORPTION IN MAN

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Erythorbic acid (ErA) is one of the stereoisomers of L-ascorbic acid (AsA). It possesses antioxidative properties similar to AsA and is used widely in Japan as an antioxidant in foods with no dosage limitation, because animal tests show that it has no toxic effects. The results of our biological monitoring studies in humans showed that absorption and/or excretion of ErA may be less than that of AsA after administration of simultaneous oral doses. However, further tests must be done to confirm these findings. Because the concentration of food additives in biological samples is very low, we first tried to simultaneously determine these two acids by high performance capillary electrophoresis (HPCE).Methods : The HPCE procedure called micellar electro kinetic chromatography (MEKC) using a buffer solution containing micelles of ionic surfactant (e.g. SDS), has been used to simultaneously determine AsA and ErA in standard solutions and urine samples spiked with AsA and ErA.10nl of sample was siphoned into the capillary. The proposed method used a 500 mm*75mum i.d. fused silica column and a 10mM borate buffer containing 50 mM SDS (pH 11.0). The determination was carried out using a 15kV separation voltage at 25ﾟC.The UV absorption was measured at lambda=265nm.Results : The AsA peak migrated at 5.7min and the ErA peak at 6.1 min in the standard solution. In the urine samples, the AsA peak migrated at 5.2 min and the ErA peak at 5.6min. The separation was complete in eight minutes and there was no overlapping with the creatinine peak (4.9min) and uric acid peak (5.8min). The recovery of AsA and ErA from the urine was 98% and 88%.respectively.