结冷胶中残留溶剂测定方法的优化探讨

Discussion on the optimization of the determination method of residual solvents in gellan gum

目的:建立顶空气相色谱法同时测定结冷胶中的残留溶剂异丙醇和乙醇。方法:在顶空平衡条件下用0.5mol·L^(-1)氢氧化钠溶液将结冷胶水解后,采用顶空气相色谱法测定,色谱柱为DB-624柱(30 m×0.53 mm,3.0μm);柱温为50℃;进样口温度为230℃;检测器为FID,温度为260℃;顶空瓶平衡温度为80℃,平衡时间为60 min。结果:乙醇在0.051~1.0209 mg·mL^(-1)范围内线性关系良好(r=0.999),异丙醇在0.0077~0.1543 mg·mL^(-1)范围内线性关系良好(r=0.999);乙醇平均回收率分别为104.2%(RSD=2.3%,n=9),异丙醇的平均回收率为100.6%(RSD=0.9%,n=9)。测定样品22批,结果乙醇含量均小于0.3%,异丙醇含量均小于0.04%。结论:该法操作较为简单、绿色环保,且方法专属性、精密度、重复性、耐用性均良好,可用于评价结冷胶中的残留溶剂情况。

Objective:Establishment of headspace gas chromatography for simultaneous determination of residual solvents isopropanol and ethanol in gellan gum.Methods:Gellan gum was hydrolyzed with 0.5 mol·L^(-1)sodium hydroxide solution under headspace equilibrium conditions,and then determined by headspace gas chromatography.The column was DB-624(30 m×0.53 mm,3.0μm);the temperature was set at 50℃;the inlet temperature was set at 230℃;the detector was FID,and the temperature was set at 260℃;the equilibration temperature of the headspace vial was set at 80℃,and the equilibration time was 60 min.Results:The linear relationship was good in the range of 0.051-1.0209 mg·mL^(-1)for ethanol(r=0.999),and the linear relationship for isopropanol was good in the range of 0.0077-0.1543 mg·mL^(-1)(r=0.999);the average recovery rate of ethanol was were 104.2%(RSD=2.3%,n=9),respectively,and the average recovery of isopropanol was 100.6%(RSD=0.9%,n=9).22 batches of samples were tested,and the results showed that the ethanol content was less than 0.3%,and the isopropanol content was less than 0.04%.Conclusion:The method is relatively simple,environmentally friendly,and has good method specificity,precision,repeatability,and durability,and can be used to evaluate the residual solvent in gellan gum.