Abstract: An ion chromatography method was presented to determine chlorine in hogwash oil and edible oil. Oil samples were ashed in muffle furnace at 550 ℃for 4 h with calcium oxide, cooled down, extracted with water in an ultrasonic field, and purified on an On Guard Na Ⅱ SPE column for eliminating metal ions before ion chromatographic analysis. The chromatographic separation was carried out on an IonPac AS19 (4 mm× 250 mm) column using 30.0 mmol/L KOH as mobile phase at a flow rate of 1.0 mL /min. The injection volume was 500μL. The external standard method was used to quantify chlorine. The detection limit of the method was 0.004 mg/L and a good linear relationship was observed over the range from 0.004 to 0.8 mg/L (r = 0.9992). The average recovery rate and RSD were 88% and 3.1%, respectively. This method proved easy to use, rapid, sensitive and accurate.

Key words: ion chromatography, hogwash oil, edible oil, chlorine