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Sequential flow‐injection potentiometric determination of iodide and iodine in povidone iodine pharmaceuticals
Author(s) -
Hassan Saad S. M.,
Marzouk Sayed A. M.
Publication year - 1993
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140050921
Subject(s) - iodide , iodine , chemistry , potentiometric titration , detection limit , flow injection analysis , resorcinol , ascorbic acid , iodate , sodium iodide , inorganic chemistry , analytical chemistry (journal) , chromatography , electrode , organic chemistry , food science
A potentiometric sensor‐based flow‐injection system for determining iodide is described. The system utilizes a flow‐through sandwich cell and incorporates iron (II)‐tris bathophenanthroline iodide ion pair complex as an exchange site in a PVC matrix membrane. The sensor displays a fast response for 10 −1 to 10 −6 M iodide ion with an anionic slope of 59.1 ± 0.3 mV/concentration decade over the pH range 1 to 11. The experimental setup offers a precise, sensitive, selective and high sample throughput technique for determining iodide and iodine over a wide range of concentration. The limit of detection is 0.5 ppm iodide in a 20 μL sample. The average recovery is 99.8%, and the mean standard deviation is 0.5%. Sequential flow‐injection determination of iodide and iodine in some pharmaceutical preparations containing povidone iodine is performed by sample injection in a sodium sulfate‐ascorbic acid stream and monitoring of the total iodide equivalent to I − and I 2 . This is followed by injection of a second sample in an alkaline resorcinol stream and measuring of the iodide equivalent to I − and 1/2 I 2 . Iodine and iodide concentrations are calculated from the consecutive signals. The method gives results in good agreement with those obtained by the United States Pharmacopeia.