New method for the spectrophotometric determinations of ascorbic acid and dehydroascorbic acid

Szepesi, G.

doi:10.1007/bf00423802

Cited by 9 publications

(2 citation statements)

References 2 publications

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“…Ascorbic acid is determined after oxidation with mercuric chloride and condensing the DHAA with 4,5-disubstituted phenylenediamine 36 , which gives the quinoxaline derivative used for absorbance measurement. The method involving 4-nitro-1,2-phenylenediamine 37 (λ max =375 nm) is very complex and laborious, since it involves many timeconsuming steps including purification of the sample with anionic Sephadex column.…”

Section: Resultsmentioning

confidence: 99%

Photometric Methods for the Determination of Vitamin C

1998

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Section: Resultsmentioning

confidence: 99%

Photometric Methods for the Determination of Vitamin C

1998

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“…DHA is also an important, interesting but somewhat enigmatic compound in biological systems [1]. Numerous analytical methods, including spectrophotometry [2,3], amperometry [4,5], voltammetry [6,7], iodometric titration [8], have been developed for the determination of H 2 A in foods, pharmaceuticals and biological samples. High performance liquid chromatography (HPLC) is the most widely used technique for vitamin C determination.…”

Section: Introductionmentioning

confidence: 99%

Rapid determination of ascorbic acid, dehydroascorbic acid, and total vitamin C by electrochemiluminescence with a thin-layer electrochemical cell

Takahashi

Jin

2009

Anal Bioanal Chem

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This paper reports on a rapid and sensitive method for the simultaneous determination ascorbic acid (H 2 A), dehydroascorbic acid (DHA) and total vitamin C by electrochemiluminescnece (ECL) using a thin-layer electrochemical cell. Significant ECL signals can be generated by the anodic oxidation of Ru(bpy) 3 2+ in presence of H 2 A or DHA in pH 8.8phosphate buffer solution. Because of the extremely small dead volume of the thin-layer cell (ca.1.5 μL), almost amount of H 2 A is assumed to be completely oxidized to DHA with a short preelectrolysis step. As a result, it is possible to determine the reductive vitamin C (H 2 A) by square wave voltammetry before the pre-electrolysis step, while total vitamin C (sum of H 2 A and DHA) is able to be determined at a subsequent ECL step. The method was employed for the determination of vitamin C in commercial beverages with the analytical results in good agreement with the certified values.

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Amperometric Differential Determination of Ascorbic Acid in Beverages and Vitamin C Tablets Using a Flow Cell Containing an Array of Gold Microelectrodes Modified with Palladium

et al. 1998

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A simple and attractive method for quantification of ascorbic acid (AA) in beers, soda, natural juices and commercial vitamin C tablets was achieved by combining flow injection analysis and amperometric detection. An array of gold microelectrodes electrochemically modified by deposition of palladium was employed as working electrode which was almost unaffected by fouling effects. Ascorbic acid was quantified in beverages and vitamin tablets using amperometric differential measurements. This method is based on three steps involving the flow injection of: 1) the sample plus a standard addition of AA, 2) the pure sample, and 3) the enzymatically-treated sample. The enzymatic treatment was carried out with Cucumis sativus tissue, which is a rich source of ascorbate oxidase, at pH 7. The calibration plots for freshly prepared ascorbic acid standards were very linear in the concentration range of 0.18-1.8 mg L ¹1 with a relative standard deviation (RSD) < 1%, while for real samples the deviations were between 2.7 % to 8.9 %.

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New method for the spectrophotometric determinations of ascorbic acid and dehydroascorbic acid

Cited by 9 publications

References 2 publications

Photometric Methods for the Determination of Vitamin C

Photometric Methods for the Determination of Vitamin C

Rapid determination of ascorbic acid, dehydroascorbic acid, and total vitamin C by electrochemiluminescence with a thin-layer electrochemical cell

Amperometric Differential Determination of Ascorbic Acid in Beverages and Vitamin C Tablets Using a Flow Cell Containing an Array of Gold Microelectrodes Modified with Palladium

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