Determination of Trace-Level Anions in Electronic-Grade γ-Butyrolactone (GBL) for Lithium Ion Batteries with 2D Ion Exclusion-Ion Exchange Chromatography Coupled with Valve-Switching Technique

An ion chromatography method that based on valve-switching technique has been proposed for the determination of five trace-level anions in electronic grade γ-butyrolactone within a clean environment. The test system consists of an ion exclusion column, a concentrator column, and an anion exchange column connected in series via two 6-ports valves in a Dionex Aquion ion chromatograph. It is the basis for the analysis of trace-level anions in electronic grade γ-butyrolactone, such as test environment, containers, consumables, reagents, etc. The valves were switched several times for removing complex matrix, concentrating and separating the five anions. The chromatographic conditions were optimized with a limit of detection (S/N = 3) were ranging from 3 to 82 ng/kg, while the limit of quantitation (S/N = 10) were in the range of 10 to 275 ng/kg respectively. The relative standard deviations (RSDs) of peak area were less than 4.7% within 6 injections and the linear correlation coefficient of the calibration curve was ≥ 0.998. The recovery rate of 0.2 ng, 0.8 ng and 2.0 ng were from 85.3% to 101.5%. This method could meet the detection requirements of trace-level anions in electronic grade γ-butyrolactone for lithium-ion batteries.