提出了气相色谱法测定甲醇中8种苯系物含量的方法。取甲醇样品200.00 mL,用二硫化碳5 mL和水200 mL进行萃取,静置分层后,倒出200 mL上清液,于二硫化碳液层中再加入水200 mL,充分振荡3 min,静置分层后倒出上清液200 mL;重复水洗3次后,取二硫化碳液层进行气相色谱分析。用DB-WAX毛细管柱分离,氢火焰离子检测器测定。8种苯系物的质量浓度均在1.0~40 mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.25~0.45 μg·L-1之间。方法用于测定工业甲醇样品中苯系物的含量,并进行加标回收试验,回收率在96.9%~101%之间,测定值的相对标准偏差(n=10)在0.56%~2.5%之间。

A method of GC for the determination of 8 benzene homologues in methanol was proposed. The methanol sample (200.0 mL) was extracted with 5 mL of CS2 and 200 mL of water. After phase separation, 200 mL of the upper layer was poured out, and another portion of 200 mL of water was added to the lower layer of CS2, shaked for 3 min to perform the 1st back-washing, and the back-washing with water was repeated 2 times more in the same way. Finally, the CS2 layer was taken for GC analysis. DB-WAX capillary column was used for seperation, and hydrogen FID used for determination. Linear relationships between values of peak area and mass concentration of 8 benzene homologues were kept in the same range of 1.0-40 mg·L-1, with detection limits (3S/N) in the range of 0.25-0.45 μg·L-1. The proposed method was applied to the determination of benzene homologues in industrial methanol, and recovery was tested by standard addition method, giving values of recovery in the range of 96.9%-101% with RSD′s (n=10) in the range of 0.56%-2.5%.