Detection of iodide in geologic materials by high-performance liquid chromatography

A method for the detection of iodide in geologic materials including surface and ground waters, brines, and extracts from sediment, plants, soil and crude oil is presented. The detection limit of the HPLC system under ideal conditions is 0.45 ng. Applications of the method are related to the use of the I-129 isotope system in environmental science and geology. Ion chromatography is used to monitor extraction of I and to determine total I concentrations from samples prepared for measurement of I-129/I ratios by accelerator mass spectrometry. Methods of extraction and sample preparation are described.