The analysis of the ascorbic acid (vitamin C; A.A.) contained in some foodstuff and pharmaceutical samples was performed by a new microcalorimetric method. It uses the oxidation of the vitamin C catalysed by the enzyme ascorbate oxidase (A.O.), which gets the specificity of the reaction. The calibration curve was built under the following operative conditions: 25.00 8C, pH 5.6, [A.O.]/11 IU ml1, the linearity range is: 35/A.A.5/270 mg l1. The method has been applied to many samples to determine the vitamin C quantity. Each analysis takes about 20 min (the assay time is instead about 5 min, the slow step is due to the time necessary for the calorimeter to return to the operative temperature after washing). No pre-treatments of the samples are requested, unless their solubilisation in buffer. The variations of vitamin C concentration were studied in function of storage time and light exposition. Using a known HPLC assay to compare its reliability on a drug analysis has validated the proposed method.
Food analyses: a new calorimetric method for ascorbic acid (vitamin C) determination / Antonelli, Marta Letizia; D'Ascenzo, Giuseppe; Lagana', Aldo; P., Pusceddu. - In: TALANTA. - ISSN 0039-9140. - STAMPA. - 58:5(2002), pp. 961-967. [10.1016/s0039-9140(02)00449-6]
Food analyses: a new calorimetric method for ascorbic acid (vitamin C) determination
ANTONELLI, Marta Letizia;D'ASCENZO, Giuseppe;LAGANA', Aldo;
2002
Abstract
The analysis of the ascorbic acid (vitamin C; A.A.) contained in some foodstuff and pharmaceutical samples was performed by a new microcalorimetric method. It uses the oxidation of the vitamin C catalysed by the enzyme ascorbate oxidase (A.O.), which gets the specificity of the reaction. The calibration curve was built under the following operative conditions: 25.00 8C, pH 5.6, [A.O.]/11 IU ml1, the linearity range is: 35/A.A.5/270 mg l1. The method has been applied to many samples to determine the vitamin C quantity. Each analysis takes about 20 min (the assay time is instead about 5 min, the slow step is due to the time necessary for the calorimeter to return to the operative temperature after washing). No pre-treatments of the samples are requested, unless their solubilisation in buffer. The variations of vitamin C concentration were studied in function of storage time and light exposition. Using a known HPLC assay to compare its reliability on a drug analysis has validated the proposed method.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
