A simple, innovative method for the determination of iodide by using gas‐phase molecular absorption spectrometry after volatile species evolution

Abstract

A simple, innovative method for the determination of iodide has been developed and described based on evolution of halogen gas and followed by gas‐phase molecular absorption spectrometry (GPMAS) with a conventional hollow cathode lamp as primary radiation source. A convenient reaction vessel is designed for vapor generation and a flow‐through absorption tube is used to replace the atomizer of a commercial atomic absorption spectrometer. Concentrated sulfuric acid is used as reaction agent to oxidize the iodide, and the produced iodine gas is carried into light path of the absorption cell. Measurement of the molecular absorption has been performed at wavelength 518 nm with a conventional Mg lamp. The detection limit for iodide attained is about 0.89 (μg/ml and the relative standard deviation is usually less than 3% at the analyte concentration of 50 (μg/ml. An interference study shows that the proposed method is selective and effective. The method has also been tested for real sample analysis.

Key words:

• Iodide determination
• Gas‐phase molecular absorption
• Method development
• Chemical evolution
• spectrometry