离子色谱法测定瓜子中的二氧化硫残留

Determination of sulfur dioxide residues in melon seeds by ion chromatography

建立了离子色谱-抑制型电导测定瓜子中的二氧化硫残留量的方法。样品经由水蒸气蒸馏,通过3%双氧水吸收氧化得到待测液,再通过0.22μm滤膜和C18柱处理后,用IonPac AG11-HC(4*50mm)+IonPac AS11-HC(4*250mm)分离柱,1.0mL/min KOH淋洗液梯度洗脱,抑制电导检测。在优化色谱条件下,二氧化硫残留量在一定范围内线性良好,检出限为0.059mg/kg。加标回收率在88.78%~98.13%之间。该方法灵敏度高,重现性好,测定结果可靠。

An ion chromatography （IC） method with suppressed conductivity detection was developed for determination of sulfur dioxide residues in melon seeds. The samples were extracted by steam distil- lation, absorbed by 3% hydrogen peroxide, then filtered umn. The IC separation was performed on IonPac AGll with 0.22μm membrane and purified by C18 col- （50 mm× 4 mm）guard column, and IonPac AS11 （250 mm× 4 mm）analytical column using potassium hydroxide solution with gradient elution at 1 mL/min. Under the optimized separation conditions, the linear equation was y = 9. 234x--0. 0102 with correlation coefficient of 0. 9993, and the relationship of sulfur dioxide was good. The average recovery for sulfur di- oxide ranged trom 88.78% to 98.13% and limit of detection （3S/N） was 0. 059 mg/L. This method is ac- curate, reliable and sensitive for determination of sulfur dioxide residues in melon seeds.