ISSN:
1432-1130
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A new simple, rapid and sensitive spectrophotometric flow injection method for the determination of trace iodide is described based on an ion associate of iodate (IO3 –) with 2- (3,5-dibromo-2-pyridylazo)-5-diethylamino-phenol (3,5-Br2-PADAP) and thiocyanate (SCN–). In a strongly acidic medium, this unstable violet product was formed with an absorption maximum at 605 nm. Flow injection is an ideal method to reproducibly monitor the transient signal. Various parameters were optimized using the Super Modified Controlled Weighted Centroid Simplex Method (SMCWC). Under the optimum experimental conditions, iodide could be determined in the range of 1.00 × 10–6 and 2.4 × 10–5 mol l–1. The correlation coefficient of the calibration curve is 0.9991. With a sampling frequency of 80 h–1, the detection limit for iodide is 5.0 × 10–7 mol l–1. The proposed method has been applied to the determination of trace iodide after oxidizing I– in table salt or laver to IO3 –. In addition, the mechanisms of the ion association reaction was studied.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002160050292
