DETERMINATION OF ASCORBIC-ACID IN FRUIT AND VEGETABLES USING NORMAL POLAROGRAPHY

The ascorbic acid content of fruit and vegetables was determined by normal polarography. It was found that oxalic acid and EDTA protected the vitamin during the sample preparation procedure but oxalic acid was preferred to be used for polarographic analysis. Citrate buffer was used as the supporting electrolyte since it was already present in fruit and vegetables and resisted the change in pH upon the addition of the fruit extract. The most suitable pH of the supporting electrolyte was determined to be 4.5. A procedure is suggested for the determination of ascorbic acid in fruit and vegetables. The standard deviation for the method based upon the pooled precision data was found to be 1.0 for tomatoes and 3.1 for oranges.