Chemically modified carbon paste electrode for iodide determination on the basis of cetyltrimethylammonium iodide ion-pair.
A new carbon paste electrode (CPE) for the determination of iodide ion based on a cetyltrimethylammonium iodide (CTMAI) ion pair as an electroactive material is described. The electrode shows a linear response for iodide ion over the concentration range of 4 x 10(-5) M to 1 x 10(-1) M with a lower detection limit of 4 x 10(-5) M at 25 degrees C. The electrode has a Nemstian slope of -55.0 +/- 0.4 mV/decade and a fast potential response of 45 s, which is almost constant over a pH range of 5.0 - 9.0. Selectivity coefficient data of the CTMAI-CPE for some common ions show negligible interference, and the electrode has high selectivity towards the iodide ion. An average recovery of 101.83% with a relative standard deviation of 1.53% has been achieved for the determination of iodide in Flaxedil (gallamine triethiodide) ampoules, a muscle relaxant drug. The electrode has been examined for the determination of iodide in saline water; the results were found to compare favorably with those obtained using Metrohm iodide ISE. The electrode has been utilized as an end-point indicator electrode for the determination of Hg(II) and phenylmercury(I) in their aqueous solutions using potentiometric titration with a potassium iodide standard solution.
Abbas
Mohamed Noor El-Deen
MN
Microanalytical Laboratory, Applied Organic Chemistry Department, National Research Center, Dokki, Cairo, Egypt. mnoorsci@menanet.net
D002244:Carbon; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D005703:Gallamine Triethiodide / Q000032:analysis; D007454:Iodides / Q000032:analysis*; D017736:Ion-Selective Electrodes / Q000592:standards*; D008628:Mercury / Q000032:analysis; D004364:Pharmaceutical Preparations / Q000032:analysis; D010663:Phenylmercury Compounds / Q000032:analysis; D012016:Reference Values; D012680:Sensitivity and Specificity; D014867:Water
D002593:Cetrimonium Compounds; D007454:Iodides; D004364:Pharmaceutical Preparations; D010663:Phenylmercury Compounds; D014867:Water; D002244:Carbon; D008628:Mercury; D005703:Gallamine Triethiodide; D000077286:Cetrimonium