二维气相色谱技术分析车用甲醇/乙醇汽油中甲缩醛

Determination of Dimethoxymethane in Methanol/Ethanol Gasoline for Motor Vehicles by Two-Dimensional Gas Chromatography

建立了一种采用填充柱切割-反吹二维气相色谱技术分析车用甲醇/乙醇汽油中甲缩醛的方法。利用非极性填充预柱将汽油中沸点不大于正己烷的轻组分保留进入分析柱，沸点大于正己烷的重组分反吹放空，轻组分和甲缩醛经一个装填有Carbowax-1500（15%（m/m））固定相的色谱柱分离分析。采用外标法定量，甲缩醛在100~80000 mg/L范围内线性关系良好，相关系数均为0.9999，标准样品6次重复性测定的相对标准偏差分别为1.27%和1.08%，回收率在98.7%~117.0%之间，方法检出限（S/N=3）为100mg/L。该方法不需要进行样品前处理，具有操作简单，准确高效的特点，是甲醇/乙醇汽油中甲缩醛测定的理想分析方法。

A simple and efficient method based on two-dimensional gas chromatography with the packed column switching-back flushing technique was established for the determination of dimethoxymethane in methanol/ethanol gasoline.With the use of a non-polar pre-column,the components in gasoline were successfully separated by back flushing out the components not lighter than the n-hexane, while the light components and dimethoxymethane were flushed into an analytical column packed with Carbowax-1500（15%（m/m））. External standard method was applied to the quantitative analysis.The method showed a good linearity between 100 to 80000 mg/L with the correlation coefficient of 0.9999 and with the relative standard deviation（RSD）of 1.27% and 1.08%.The recoveries ranged from 98.7% to 117.0% and the detection limit（S/N=3）was 100 mg/L.The method was performed without pretreatment and was proved to be simple,accurate and efficient,it’s an ideal method for the analysis of dimethoxymethane in methanol/ethanol gasoline.