Determination of trace elements in salt lake brines using inductively coupled plasma optical emission spectrometry after magnesium hydroxide precipitation

Abstract

A magnesium hydroxide coprecipitation method for the determination of trace elements in high-salt samples from salt lake brines by inductively coupled plasma optical emission spectrometry (ICP-OES) was developed. Some effects on the coprecipitation and analysis, such as the pH value and Na and Mg amounts in primary brines, have been thoroughly investigated and optimized. After adjusting the pH to 8.70, associated with sodium hydroxide, the complicated matrix was removed from high salt brines, and thus trace amounts of Al, Co, Cu, Fe, Mn, Ni, V, and Zn were simultaneously coprecipitated and precisely determined. Recoveries of all the determined trace elements in the samples of both synthesized and real salt lake brines were more than 90%. The detection limit in the range of 0.62–14.4 μg L⁻¹ was obtained and the precision was less than 3% relative standard deviation. The optimized method has been successfully applied for the determination of trace elements in the intercrystal brine mined from Dachaidan salt lake located in the Qaidam Basin, China.