Determination of K, Na, and Mg in Brine by Liquid Cathode Glow Discharge—Optical Emission Spectrometry (LCGD-OES) with Interference Suppression

The determination of K, Na, and Mg in brine is important for its effective utilization. Liquid cathode glow discharge-optical emission spectrometry (LCGD-OES) is a successful approach for the determination of these elements in brine. However, matrix interferences reduce the accuracy using a standard curve. Here a correction method based upon the mutual interferences between K, Na, and Mg is reported to improve the accuracy of brine analysis. To verify the performance, LCGD-OES was employed to analyze four samples using the optimized operating voltage and sample flow rate. The results showed that the relative errors of the concentrations of K and Na in the brine were from 1.79% to 8.65% and 3.88% to 6.49% compared to inductively coupled plasma optical-emission spectrometry (ICP-OES). The reported correction method significantly reduced matrix interferences for the determination of K and Na. Additionally, Mg in brine was determined using Al as the internal standard.