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
Website: @unf

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Classification: Beverage -> non alcoholic -> lemonade

Citations 2

"The Application Of Strongly Oxidizing Agents In Flow Injection Analysis. 4. Manganese(IV) And Copper(III)"
Anal. Chim. Acta 1988 Volume 211, Issue 1-2 Pages 99-104
W. E. van der Linden, G. den Boef and W. Ozinga

Abstract: Both oxidizing reagents were prepared under batch conditions and fed to the flow injection device from a strongly alkaline stock solution. Sexavalent Te was added to keep both Cu(III) and Cu(II) in solution, as well as Mn(IV) formed after the reduction of Mn(VI). The stability of both reagents and their oxidizing ability depend on the concentration. of Te(VI) and on the alkalinity of the solution The reactions of most analytes tested with Mn(VI) required the use of a heated (65°C) coil. The flow systems used for analyzes with each reagent are presented, and applications of each are discussed. The Mn(VI) reagent is particularly useful in the determination of 0.1 to 0.01 mM monosaccharides; this is demonstrated for the determination of fructose and glucose in lemonade.
Monosaccharides Fructose Glucose Spectrophotometry Heated reaction Merging zones

"Electrochemical FIA System Combined With An Immobilized Enzyme Reactor For The Determination Of Ascorbic Acid"
Ernaehrung 1993 Volume 17, Issue 11 Pages 605-608
Friedrich, O.;Sontag, G.;Pittner, F.

Abstract: A simple and rapid method for determination of ascorbic acid (I) was developed by combining an FIA system with an enzyme reactor (L-ascorbate oxidase), an inactive reactor and an amperometric detector. If a sample containing I and another oxidizable substance are 1st passed through the inactive reactor both of them will be detected at +0.7 V. If the same sample is then passed over the enzyme reactor ascorbic acid is oxidized enzymatically and the detector detects only the other oxidizable substance. The difference of the signals is proportional to the concentration. of the I. In juices and lemonades 4.1/20.2 mg/L were found. Pharmaceutical preparations contained 20-497.2 mg/tablet. The relative standard deviation was 0.9-11.7%. (SFS)
Ascorbic acid Electrochemical analysis Immobilized enzyme Reactor