Abstract:

The iterative upgrading process of alcohol ether carboxylic acid （AEC） products has significantly accelerated in recent years, with new products continuously emerging. Existing analytical methods are increasingly inadequate to meet the testing demands for all categories of AEC products. Therefore, in this study, a method of ion chromatography was established for determining the monochloroacetate ion and chloride ion in AEC. In the experiment, a Qingdao Shenghan SH-AP-1 anion-exchange column （5.5 μm, 4.0 mm×250 mm） was employed for target ion separation. Isocratic elution was operated by using potassium hydroxide solution as the mobile phase. Coupled with a suppressed conductivity detector, quantitative analysis was performed by external standard method. The optimized conditions of ion chromatography were determined as follows: The 5 mmol/L KOH solution was used as mobile phase at a flow rate of 0.8 mL/min. Under this condition, the target ions achieved efficient baseline separation. Methodology validation demonstrated that both target anions exhibited good linearity in the concentration range of 1-50 μg/mL, with correlation coefficients （r） exceeding 0.999. The spiked recoveries at three concentration levels ranged from 93.0% to 98.4%, with relative standard deviations （RSD） between 0.4% and 3.4%. All performance metrics met the technical requirements for real-sample analysis. This method was simple to operate and had excellent separation effect, indicative of good precision, accuracy, and repeatability. It was effective for precise quantitative detection of monochloroacetate ion and chloride ion in various types of AEC products. Furthermore, it enabled accurate screening of AEC products with low chloride type and low monochloroacetic acid type, as well as oxidation-processed products, providing reliable technical support for quality control of AEC products.

Key words: ion chromatography, alcohol ether carboxylic acid, monochloroacetate ion, chloride ion, conductivity detector