University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Fruit

Classification: Fruit -> lemon

Citations 2

"A New Simple And Accurate Turbidimetric Method For Determination Of Ascorbic Acid In Pharmaceuticals And Fruits"
J. Chin. Chem. Soc. 2002 Volume 49, Issue 5 Pages 949-956
Mir Ali Farajzadeh and Sepideh Nagizadeh

Abstract: An accurate, simple, solvent free and inexpensive turbidimetric method is presented for the determination of ascorbic acid in pharmaceutical preparations and fruits. It needs no special reagents or precautions. In this method HgCl2 oxidizes ascorbic acid in citrate buffer at a pH of about 4 and produced Hg2Cl2 precipitate as monitored by turbidance measurements. The procedure is very simple and the experimental conditions such as temperature, ionic strength, stirring and time are not critical. High sensitivity and selectivity are two other advantages of this method. Linear dynamic range of the calibration curve is between 3-120 µg/mL with limit of detection (LOD) 1 µg/mL, which allows the ascorbic acid contents of most fruits and vegetables to be analyzed. On the other hand, the interference studies show that common compounds in real samples and colored substances have no considerable effect on the determination. Only filtration of some samples is necessary and other treatments, which are performed prior to determination of ascorbic acid by other analytical methods, are eliminated. Finally, ascorbic acid concentration in different samples is determined by the proposed method and obtained results are compared with the results of the official 2,6-dichlorophenolindophenol or iodimetric methods and a good agreement is obtained. This method is very sensitive in comparison with iodimetry and is very fast relative to the 2,6-dichlorophenolindophenol method.
Ascorbic acid Turbidimetry Interferences Optimization Method comparison

"Flow Injection Determination Of Total Vitamin C Using Cucumber Juice Carrier"
Bunseki Kagaku 1990 Volume 39, Issue 11 Pages 793-795
Uchiyama, S.;Suzuki, S.

Abstract: The total ascorbic acid (I) content of lemons, mandarins and kiwi fruit was measured by a flow injection method after reduction of dehydroascorbic acid to L-ascorbic acid. Cucumber juice (filtered and centrifuged), containing ascorbate oxidase, was used as a carrier and the O consumed in the enzymatic reaction was detected at an O electrode. At a flow rate of 1.3 mL min-1 the peak currents were proportional to total I concentration. in the range 0.1 to 1 mM. The results were compared with those obtained by spectrophotometry. Ascorbate oxidase was stable in cucumber juice for 7 days.
Ascorbic acid Electrode Electrode Enzyme Method comparison