Microscale Determination of Vitamin C by Weight Titrimetry

Measuring Vitamin C Content of Commercial Orange Juice Using a Pencil Lead Electrode

“…The use of pencil lead as a sensitive nitrate ion-selective electrode , for a simple surface chemistry experiment and for potentiometric titrations , has been described in this Journal . The determination of vitamin C using a variety of methods has also been described in this Journal : gold electrodes modified with self-assembled monolayers , biopotentiometric iodometric back-titration , microscale weight titrimetry , high-pressure liquid chromatography , titration using 2,6-dichlorophenolindophenol and N -bromosuccinimide , and a combination of iodometric and coulometric titrimetry .…”

A Laboratory Experiment for Rapid Determination of the Stability of Vitamin C

“…The determination of vitamin C (ascorbic acid) in undergraduate laboratories is a fairly common practice because students are eager to practice new skills on substances that are relatively familiar to them. A large number of these procedures are based on teaching the students by means of the classic iodimetric or iodometric titration of vitamin C. − Another, less popular titration method involves the use of 2,6-dichlorophenol indophenol. , Instrumental methods of analysis, especially electrochemistry and HPLC, are also popular, but perhaps in more advanced undergraduate and graduate lab courses. ,− Because of their relative complexity and need for more advanced laboratory skills none of these techniques seemed suitable for our first-year general, organic, and biological (GOB) chemistry laboratory course. Therefore, we developed a precise, engaging laboratory experiment that could involve relatively simple laboratory instrumentation and skills appropriate for GOB students.…”

New, Milder Hypervalent Iodine Oxidizing Agent: Using μ-Oxodi(phenyliodanyl) Diacetate, a (Diacetoxyiodo)benzene Derivative, in the Synthesis of Quinones

“…In the past 10 years or so, several green chemistry undergraduate experiments have been published . Hypervalent iodine reagents have been used in undergraduate teaching laboratories for the oxidation of alcohols (2-iodoxybenzoic acid, IBX), for the amination of the benzylic position (diacetoxyiodobenzene, PIDA, along with a rhodium-based reagent), and for the oxidation of the enediol in ascorbic acid titrimetry . Although electrophilic aromatic substitution and acidic K 2 Cr 2 O 7 have been used to synthesize quinones in the undergraduate teaching laboratory, the most popular reagent is cerric ammonium nitrate .…”

“…1 Hypervalent iodine reagents have been used in undergraduate teaching laboratories for the oxidation of alcohols (2-iodoxybenzoic acid, IBX), 2 for the amination of the benzylic position (diacetoxyiodobenzene, PIDA, along with a rhodium-based reagent), 3 and for the oxidation of the enediol in ascorbic acid titrimetry. 4 Although electrophilic aromatic substitution 5 and acidic K 2 Cr 2 O 7 6 have been used to synthesize quinones in the undergraduate teaching laboratory, the most popular reagent is cerric ammonium nitrate. 7 However, undergraduates have not been exposed to the use of hypervalent iodine reagents, which have been used extensively in the synthesis of quinones, 8,9 including the synthesis of quinones with medicinal properties such as the antituberculosis natural product (+)-puupehenone.…”