1,3,3-Trimethyl-2-[3-(l,3,3-trimethyl-l,3-dihydroindol-2-ylidene)propenyl]-3if-indolium Chloride, a Highly Sensitive Reagent for the Spectrophotometric Determination of Selenium

摘要

A highly sensitive spectrophotometric method for the determination of selenium is reported. The method is based on the oxidation of iodide by selenium(IV) and the spectrophotometric detection of the liberated iodine in the form of an ion associate with l,3.3-trimethyl-2-[3-(1,3,3-trimethyl-l,3-dihydroindol-2ylidene)propenyl]-3H-indolium chloride reagent. The appropriate reaction conditions have been established. The molar absorptivity is 2.4 * 105 dm3 mol-1 cm-1 at 556 nm wavelength. The absorbance of the coloured extracts obeys the Beer's law in the range from 0.01 to 3.84 mg dm-3 of Se(IV).