Dehydroascorbic quantitative determination

JT Vanderslice, DJ Higgs. Quantitative determination of ascorbic, dehydroascorbic, isoascorbic, and dehydroisoascorbic acids by HPLC in foods and other matrices. J Nutr Biochem 4 184-190, 1993. 

Ascorbic acid can be semi-quantitatively estimated with the comparison method after colour reaction with molybdophosphoric acid [61]. The suggestion of Stbohecker et al. [129, 130] for quantitative determination has met with approval. The red zone of dehydroascorbic acid-DNP is scraped off, eluted with 85% sulphuric acid, filtered or, better, centrifuged, and the light absorption of the solution measured at 520 to 525 nm against water as blank. The analysis result is worked out with the help of a standard solution which is treated identically. 

The potential of PBI LC-MS in the analysis of various vitamins was explored by Careri et al. [99-100]. The fat-soluble vitamins A, D, and E were analysed in food and multivitamin preparations [99]. Absolute detection limits in SIM mode were 0.6-25 ng after fast leversed-phase separation using a 97% aqueous methanol as mobile phase. Mass spectra in El, positive-ion and negative-ion Cl were obtained and discussed. The mass-spectral and quantitative performance of PBI LC-MS in the analysis of eleven water-soluble vitamins was also explored [100]. Detection limits were determined in SIM mode under positive-ion Cl, and were below 15 ng for ascorbic acid, nicotinamide, nicotinic acid, and pyridoxal, around 100 ng for dehydroascorbic acid, panthothenic acid, and thiamine, and above 200 ng for biotin, pyridoxamime, and pyridoxine. Riboflavine was not detected. 

Ascorbic acid, CgHgOs (vitamin C), is a reducing agent. The amount of this acid in solution can be determined quantitatively by a titration procedure involving iodine, I2, in which ascorbic acid is oxidized to dehydroascorbic acid,... 

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See also in sourсe #XX -- [ ]

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