气相-液相色谱联合分析偏三甲苯氧化产物

Analysis on oxidation products of 1,2,4-trimethylbenzene by GC and HPLC jointly

针对偏三甲苯氧化过程中产物复杂、分析困难的问题,开展了气相色谱-液相色谱联合分析方法研究。使用岛津GC-2014C气相色谱仪,采用SE-54色谱柱(0.32 mm×30 m,薄膜厚度0.25μm),氢火焰离子化检测器,定量分析其中低沸点产物(偏三甲苯、醇、醛以及甲基羧酸产物等);使用安捷伦Aglient-1200液相色谱仪,采用C18色谱柱(5 mm×250 mm,粒度5μm),以甲醇-水为二元流动相,分析高沸点产物(均苯四甲酸、偏苯三甲酸及苯二甲酸等)。通过标准曲线方法获得相对摩尔校正因子,并以4-甲基邻苯二甲酸(在气相色谱和液相色谱均出峰)作为桥梁物质将2种分析方法关联,实现产物的定量分析。准确度实验表明分析误差均小于1.0%。

A gas chromatography-liquid chromatography combined analysis method is developed to address the complexity and analytical challenges in the oxidation process of 1,2,4-trimethylbenzene.A Shimadzu GC-2014C gas chromatographic instrument equipped with an SE-54 column(0.32 mm×30 m,a film thickness of 0.25μm)and a hydrogen flame ionization detector are used to quantitatively detect the low-boiling point products such as 1,2,4-trimethylbenzene,alcohols,aldehydes,and carboxylic acid derivatives.An Agilent-1200 liquid chromatography system with a C18 column(5 mm×250 mm,a particle size of 5μm),and a binary mobile phase of methanol-water are employed to detect the high-boiling point products,including 1,2,4,5-benzenetetracarboxylic acid,1,2,4-trimellitic acid,and terephthalic acid.Relative molar correction factors are obtained through using the standard curve method.4-Methylphthalic acid,which exports peaks at both gas and liquid chromatography,is served as a bridging substance to correlate the two analysis methods for quantitative analysis of the products.Accuracy experiments demonstrate that the analysis errors are all below 1.0%.