RESUMEN
OBJECTIVE: To establish a method of on-line matrix elimination together with ion chromatographic for determination of residual tetraethylammonium bromibde(TEAB) which acts as phase transfer catalyst in clopidogrel sulfate. METHODS: An ion excluding column Dionex IonPac NG1 was used for the separation of TEAB from clopidogrel sulfate, using 20 mmol·L-1 MSA as eluent. A pre-concentration column Dionex CG17 was used to enrich the trace TEAB. After being switched to analytical system, the separation was performed on Dionex ICS3000 using Dionex IonPac CS17 as analytical column, and suppressor was not required. 5 mmol·L-1 MSA containing 35% acetonitrile was used as mobile phase. RESULTS: The RSDs of retention time and peak area were good. The recoveries of TEAB were between 97.8%-103.3%. The calibration curves of analytes were linear in the range between 0.4 and 10.0 μg·mL-1. The limit of detection reached 0.2 μg·mL-1. CONCLUSION: This method can be applied to detect trace kation in pharmaceutical chemicals.