title: Flow injection spectrophotometric or conductometric determination of ascorbic acid in a vitamin C tablet using permanganate or ammonia.
abstract: Two simple flow injection (FI) procedures for the determination of ascorbic acid content in a vitamin C tablet are proposed: spectrophotometric involving injection into a stream of acidic potassium permanganate solution and monitoring its color change due to the redox reaction; FI conductometry based on the neutralization of ascorbic acid injected into a flowing ammonia solution yielding a change in conductivity. The procedures have been applied to the analysis of locally commercial vitamin C tablet samples. A through-put of at least 90 injections h(-1) can be achieved. The relative standard deviation was found to be 2.5% (for a 50 mg vitamin C tablet; n=7) for both. Results obtained by either procedure agree with a standard titrimetric method.
authors.affiliation: Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: K
authors.initials: K
authors.lastname: Grudpan
authors.forename: K
authors.initials: K
authors.lastname: Kamfoo
authors.forename: J
authors.initials: J
authors.lastname: Jakmunee