Determination of ascorbic acid, dehydroascorbic acid, and isoascorbic acid in blood

1986 ◽  
Vol 325 (5) ◽  
pp. 473-475 ◽  
Author(s):  
Jörg Schreiber ◽  
Wolfgang Lohmann ◽  
Dietrich Unverzagt ◽  
Albert Otten
Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5696
Author(s):  
Meifei Zhu ◽  
Jian Tang ◽  
Xijuan Tu ◽  
Wenbin Chen

Ascorbic acid (AA) is one of the essential nutrients in bee pollen, however, it is unstable and likely to be oxidized. Generally, the oxidation form (dehydroascorbic acid (DHA)) is considered to have equivalent biological activity as the reduction form. Thus, determination of the total content of AA and DHA would be more accurate for the nutritional analysis of bee pollen. Here we present a simple, sensitive, and reliable method for the determination of AA, total ascorbic acids (TAA), and DHA in rape (Brassica campestris), lotus (Nelumbo nucifera), and camellia (Camellia japonica) bee pollen, which is based on ultrasonic extraction in metaphosphoric acid solution, and analysis using hydrophilic interaction liquid chromatography (HILIC)-ultraviolet detection. Analytical performance of the method was evaluated and validated, then the proposed method was successfully applied in twenty-one bee pollen samples. Results indicated that contents of AA were in the range of 17.54 to 94.01 µg/g, 66.01 to 111.66 µg/g, and 90.04 to 313.02 µg/g for rape, lotus, and camellia bee pollen, respectively. In addition, percentages of DHA in TAA showed good intra-species consistency, with values of 13.7%, 16.5%, and 7.6% in rape, lotus, and camellia bee pollen, respectively. This is the first report on the discriminative determination between AA and DHA in bee pollen matrices. The proposed method would be valuable for the nutritional analysis of bee pollen.


1989 ◽  
Vol 72 (4) ◽  
pp. 681-686
Author(s):  
Hie-Joon Kim

Abstract A rapid and sensitive liquid chromatographic method for determination of total vitamin C in foods and beverages is described. Ascorbic acid and dehydroascorbic acid are extracted with sulfuric acid solution, and the dehydroascorbic acid in the extract is reduced to ascorbic acid by dithiothreitol at pH 7. The reduction is complete in 2 min at room temperature. The resulting total ascorbic acid is separated on an anion exclusion/high speed column with 20mM sulfuric acid as eluant and detected amperometrically with a platinum electrode operating at +0.6-0.8 V vs Ag/AgCl reference electrode. Dithiothreitol (retention time, 3.2 min) does not interfere with the separation and detection of ascorbic acid (retention time, 1.3 min). The dehydroascorbic acid content can be estimated as the difference in ascorbic acid content measured with and without reduction by dithiothreitol. The completeness of the reduction was demonstrated by purposely allowing the oxidation of ascorbic acid in the food extract and determining the total vitamin C after reduction. The determinations of vitamin C content in selected foods and beverages were in good agreement with the expected values. Total analysis time for vitamin C is 10 min and the detection limit is 0.1 ng. The method is specific for vitamin C, and interference by other food constituents is minimal.


1976 ◽  
Vol 59 (6) ◽  
pp. 1244-1250 ◽  
Author(s):  
Ram B Roy ◽  
Aldo Conetta ◽  
Jerry Salpeter

Abstract A specific microfluorometric method for the determination of ascorbic acid, dehydroascorbic acid, and total vitamin C in food products has been automated. The procedure developed is an adaptation of the official AOAC method (secs. 43.056–43.062), except that N-bromosuccinimide is used instead of Norit to oxidize vitamin C. Ascorbic acid is selectively oxidized by N-bromosuccinimide before other interfering substances that may be present, so this method is a highly sensitive and specific technique with extensive applicability. The proposed automated method is simple, rapid, reliable, and sufficiently sensitive to analyze as little as 2 × 10−3 to 0.1 mg ascorbic acid/ml. Analytical results obtained for ascorbic acid, dehydroascorbic acid, and total vitamin C in a wide variety of food products are reported. The analytical system developed has the capability of analyzing 50 samples/hr.


1983 ◽  
Vol 66 (6) ◽  
pp. 1377-1379
Author(s):  
Ron B H Wills ◽  
Pushparany Wimalasirl ◽  
Heather Greenfield

Abstract The vitamin C content of several fresh fruit and vegetables was determined by a liquid chromatographic (LC) method which gave simultaneous separate values for ascorbic acid and dehydroascorbic acid (DHA) and by the official AOAC methods of microfluorometry and dye-titration. The levels of ascorbic acid obtained by LC and dye-titration were in good agreement, except for a few colored products where it was difficult to determine the end point of the titration. The combined values for ascorbic acid and DHA obtained by LC and microfluorometry were in agreement for most produce, but for about one-third of the samples, the values obtained by microfluorometry were significantly higher.


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