气相色谱法测定三氯蔗糖中的甲醇残留量

Determination of Residual Methanol in Sucralose by Gas Chromatography

目的：建立测定三氯蔗糖中甲醇残留量的方法。方法：采用顶空毛细管气相色谱法。色谱柱为DB-624毛细管色谱柱,柱温采用程序升温（初始温度35℃,保持5 min,以50℃/min升温至200℃,保持5 min）,检测器为氢火焰离子化检测器。进样口温度为220℃,检测器温度为250℃,载气为氮气,流速为2.0 ml/min,分流比为10∶1,顶空温度为80℃,平衡时间为30 min,进样量为1 ml。结果：甲醇质量浓度在98.99~296.96μg/ml范围内与峰面积比值呈良好的线性关系（r=0.999 9）;精密度、稳定性、重复性试验的RSD均≤2.16%;平均加样回收率为100.20%,RSD为0.48%（n=9）。三氯蔗糖最低检测限为1.39μg/ml。3个厂家样品中有1个厂家的甲醇残留量为3.12μg/ml,另2个厂家的甲醇残留量低于最低检测限。结论：该方法简便、快捷,适用于三氯蔗糖中甲醇的残留量测定。

OBJECTIVE：To establish a method for the determination of residual methanol in sucralose. METHODS：Headspace capillary GC method was adopted. The determination was performed on DB-624 capillary column by temperature programming（initial temperature of 35 ℃,maintaining for 5 min,then raising to 200 ℃ at a rate of 50 ℃/min,maintaining for 5 min）,the detector was FID. The temperature of the injector was maintaining at 220 ℃ and that of detector at 250 ℃,carrier gas was nitrogen gas at the flow rate of 2.0 ml/min,the split ratio was 10 ∶ 1,headspace temperature was 80 ℃ and equilibrium time was 30 min,and the volume was 1 ml. RESULTS：The linear range of methanol was 98.99-296.96 μ g/ml（r=0.999 9）;RSDs of precision,stability and reproducibility tests were all no more than 2.16%;the average recoveries were 100.20%（RSD=0.48%,n=9）.The limit of detection（LOD）of sucralose was 1.39 μg/ml. In samples from 3 manufacturers,the contents of residual methanol in one manufacturer were 3.12 μ g/ml,and the other two were lower than LOD. CONCLUSIONS：This method is simple and fast,and suitable for the determination of residual methanol in sucralose.