Reduction of chloride matrix effect using silver oxide as a precipitating reagent for the determination of trace anions in chloride-rich samples via ion chromatography.

A new method was developed for the determination of trace anions in chloride-rich samples via ion chromatography by reducing the concentration of chloride ions using silver oxide as a precipitating reagent. In this method the sample pretreatment was started with the addition of silver oxide powder followed by 8 min of stirring and 2 min of centrifugation at a speed of 1500 rpm. The supernatant was diluted with a 1:10 ratio using deionized water and filtered with a 0.

[Improvement of prediction model of retention values of anions with sodium carbonate-sodium bicarbonate as eluents].

A prediction model of retention values of anions with sodium carbonate-sodium bicarbonate as eluents has been improved. The improved model is suitable for a wider range of concentrations of sodium carbonate-sodium bicarbonate eluents than the old one set up several years ago. An extensive set of experimental retention data obtained for 7 anions (nitrate, sulfate, oxalate, selenate, iodide, phosphate and arsenate ) using the eluents of varied concentrations was dealt by binary linear regression process.

Nonlinear function retention model in weak acid anion chromatography.

A nonlinear function retention model for anion chromatography is developed, which is able to predict the retention behavior of polyvalent weak acid anions using sodium hydroxide as eluent. The relationship between the retention factors of phosphate and resorcinol and eluent concentration was studied with sodium hydroxide as the eluent. Both retention factors of the analyte anions first increase then decrease with the increase of sodium hydroxide concentration.