中心切割气相色谱法测定液化石油气中甲缩醛等9种含氧化合物

Determination of Nine Oxygenates in Liquefied Petroleum Gas by Gas Chromatography with Heart-cutting Deans Switch System

采用微板流路控制Deans Switch中心切割技术、双火焰离子化检测器的双柱气相色谱系统,建立了测定液化石油气中甲缩醛等多科含氧化合物的方法.在优化的色谱条件下,将适量试样直接注入气相色谱仪中,通过阀的两次切换,将强极性的含氧化合物组分从非极性柱导入到极性柱,使得甲缩醛、二甲醚、甲基叔丁基醚、丙酮、甲醇、乙醇、丙醛和丁醛共9种含氧化合物与液化石油气中烃类组分完全分离.结果显示,甲缩醛等9种含氧化合物在0.01％（v/v）～5.0％（v/v）范围内呈现良好的线性,相关系数均大于0.99,样品重复测定5次,相对标准偏差小于3％,加标回收率在92.11％～104.40％之间,含氧化合物检出限可达0.0003％（v/v）～0.0021％（v/v）.

A method for determination of nine oxygenates such as methylal in liquefied petroleum gas （LPG） by gas chromatography with heart-cutting deans switch system was developed. By twice switch of the solenoid valve, the oxygenate compounds were cut from the non-polar column to the polar column for further separation. Under the optimal conditions, nine oxygenates, such as, methlal, dimethyl ether, methanol, ethanol, acetone, n-propyl aldehyde,/-butyl aldehyde, n-butyl aldehyde and methyl butyl ether, were well separated from paraffins of LPG. Those oxygenate compounds showed good linearity in the concentration of0.01% （V/V） to 5.0 % （V/V）, and the correlation coefficients of nine oxygenate compounds reached more than 0.99. The relative standard deviations of five times repetitive measurement were less than 3 %. The recoveries of oxygenates were between 92.11% to 104.40 %, and the detection limits of oxygenates were from 0.0003 % （V/V） to 0.0021% （V/V）.