GC顶空进样法和溶液直接进样法检测葡萄酒中甲醇的方法比较

Comparison of GC head-space injection and GC direct injection of solution in determination of methanol in wine

目的采用高效毛细管柱气相色谱法，分别使用顶空进样法和溶液直接进样法检测葡萄酒中甲醇的残留量，并进行方法比较。方法采用聚乙二醇为填料的毛细管色谱柱（30m×0．53mm，涂层厚1．0μm），程序升温的色谱条件：顶空进样法，平衡温度为60℃，平衡时间为30min；溶液直接进样法：取样品进行蒸馏，制备供试品溶液，取溶液直接进样测定。结果顶空进样法，甲醇在79．15—633．2mg／L范围内线性关系良好，检出限为1．58mg／L，加标平均回收率为101．34％，RSD=1．21％（n=6）。对同种样品采用顶空进样和直接进样法进行测定，2种方法测定结果相同。结论2种方法均可用于葡萄酒中甲醇的测定，但顶空进样法需要样品量少，无需样品前处理时繁琐的蒸馏过程，可缩短检测周期，提高工作效率。

[ Objective ] To establish methods for the analysis of methanol in wine by gas chromatography （ GC } by using head-space injection and direct injection of solution, and compare the results. [ Methods ] A capillary column （ 30 m × 0.53 ram, film coat 1.0 μm ） packed with polyethylene glycol was used with the programmed column temperature. For head space-GC method, the sam- ples had been equilibrated at 60 ℃ for 30 minutes. For direct injection of solution-GC method, and the samples were distilled to prepare the test solution and the solution were injected for the analysis. [ Results] For head-space injection, the calibration curve of methanol showed good linearity in the range of 79. 15-633.2 mg/L, the detection limit was 1. 58 mg / L, recoveries were 101.34%, and RSD = 1.21% （ n = 6 ）. For the determination of the same sample, both 2 methods had the same results. [Condusion] The 2 injection methods can be used to detect the methanol in wine, while the head-space injection method needs less sam- ple, without complex distillation during the preparation of test solution, thus, it shortens testing cycle and improves work efficiency.