In this Application Update, ion chromatography coupled with pulsed amperometric detection is used to determine iodide in brine (approximately 30% sodium chloride). This method is specific, sensitive, and rapid. Sample preparation is a simple sample dilution. Iodide is separated on the Dionex IonPac AS11 column, which contains a hydrophilic resin that is well suited to the chromatography of iodide, a relatively hydrophobic anion. Using a nitric acid eluent, the iodide ion elutes from the column in under five minutes.

The type, amount, and ratios of volcanic gases characterize and can predict impending volcanic activity and its intensity. Changes in CO2 concentration, SO2-CO2 ratios, or halide gas composition may indicate impending volcanic eruptions. Previous analyses indicate that volcanic gases are primarily composed of CO2, water vapor, and SO2 with trace amounts of arsine and halide gases. The samples are diluted by AutoDilution to determine the major components as anions and neutralized by AutoNeutralization to determine the trace gases as anions.

In this Application Update, ion chromatography coupled with pulsed amperometric detection is used to determine iodide in urine. This method is specific, sensitive, and rapid. Sample preparation involves removal of urine components with molecular weights greater than 10,000 daltons, sample dilution, and treatment with a polymeric, reversed-phase cartridge (OnGuard™-RP).

This application note includes the acetic acid digestion method for iodide extraction, coupled with an IC-PAD method for iodide detection. The IC method coupled with electrochemical detection allows for selective and sensitive determination of iodide in complex matrices. The acid digestion procedure to extract iodide was optimized for milk- and soy-based infant formulas. Sample preparation conditions to convert iodate to iodide for determining total iodine (i.e., iodide and iodate) are presented. This method is shown to be fast, robust, and sensitive.

Determination of Anions in an Artificial Volcanic Gas Condensate Sample on 2 mm IonPac AS25 Column. This sample simulates a volcanic gas condensate sample containing 100 mg/L carbonate, 10 mg/L sulfate and ppb to ppm concentrations of halides, sulfite, thiocyanate, and thiosulfate.