顶空气相色谱法测定杏脯中二氧化硫

建立顶空气相色谱测定杏脯中二氧化硫残留的方法,探讨了气液体积比、加酸量、平衡温度和平衡时间对检测结果的影响。向450 mL顶空瓶内加入5 g样品、10 g石蜡、200 mL水及25 mL盐酸溶液,于75℃平衡20 min后放至室温,抽取0.5 mL顶空气体进行定性定量分析检测。该方法标准工作曲线线性相关系数r~2为0.992,检出限和定量限分别为0.1,1.0 mg/kg,测定结果的相对标准偏差为1.9%~3.2%(n=6),样品加标回收率为89.4%~94.3%。该法操作简便、快捷,灵敏度高,人为误差小,满足杏脯中二氧化硫残留的批量检测要求。

Determination of Sulfur Dioxide Residue in Preserved Apricots by Headspace Gas Chromatography

A new method for determination of sulfur dioxide residues in preserved apricots by headspace gas chromatography was developed. The effects of gas–liquid volume ratio,the amount of acid, the equilibrium temperature and time on the test results were studied. 5 g sample, 10 g paraffin, 200 mL water and 25 mL hydrochloric acid solution were added into 450 mL headspace bottle, and after equilibrium at 75℃for 20 min, the bottle was cooled to room temperature,0.5 mL headspace gas was used to do qualitative and quantitative analysis. Results showed thatr2 of standard curve was 0.992, RSD was 1.9%–3.2%(n=6), the recovery was 89.4%–94.3%, and the limits of detection and quantifica tion of sulfur dioxide were 0.1, 1.0 mg/kg, respectively. This method is simple and fast, with good sensitiv ity and small human error. It can be used for batch determination of sulfur dioxide residues in pre served apricots.