Abstract: An ion exclusion chromatographic method for the determination of gallic acid in green tea was described. The optimal chromatographic separation was investigated on Metrosep Organic Acids (250 mm×7.8 mm) column with conductivity detection. The optimal separation was achieved using 0.006 mmol/L sulfuric acid as the eluent, 50.0 mmol/L lithium chloride as the regenerated liquid at a flow rate of 0.5 mL/min. Fluoride and 8 common acids in green tea had no interference on the determination. The total analysis time was 19 minutes. The detection limit of gallic acid was 0.1 μg/mL. The RSD of peak area for six replicate determinations was 1.34%. The recovery percentages in 4 green teas were 87.1%－96.7 %. So, the method has the advantages of simplicity, rapidity and satisfying results.

Key words: gallic acid, ion-exclusion chromatography, suppressed conductivity detection, green tea