气相色谱的胃袋式大体积进样器

STOMACH SHAPED LARGE VOLUME INJECTOR FOR GAS CHROMATOGRAPHY

将传统的气相色谱直形衬管改为胃袋式的弯曲形衬管,发展了一种新型的气相色谱进样器——胃袋式大体积进样器。大体积(200μL左右)的含被测物的溶液注入进样口后,溶液以液体形态存在于胃形衬管内,溶剂在大量载气的吹扫下被蒸发并通过分流阀溢出,而被分析物被浓缩并保留在衬管中,当溶剂吹出后,进样口改为不分流模式,快速升温使被分析物进入色谱柱。对比实验表明,胃袋式大体积进样器与常规进样器相比,峰形与常规进样器无明显差别,不存在峰形拓宽的现象,当被分析物的总进样量相同时,响应值基本相同。不同体积,相同浓度的加标样品的响应值成线性关系,相关系数在0.99以上,表明大体积进样器在不同进样量时的传输效率基本一致。

A new incurvate shape insert of inlets for GC transformed from straight shape insert has been developed, which has been named Stomach Shaped Large Volume Injector. At first, the injector is kept in a low temperature approaches boiling point of solvent in split mode, then large volume (about 200 μL) of sample is injected into the insert, and this sample stays as liquid in the stomach shaped insert. In this state, solvent is evaporated and escape under carrier gas flow from valve, while sample is concentrated and kept in the insert. Next, sample is introduced into column by raising apace the temperature of the insert in splitless mode. The Stomach Shaped Large Volume Injector takes in merit and turns away the demerit of other type of large volume injector. Chromatogram obtained by injecting the same of large volume and regular volume are compared. Contrast experiments indicate that it is not obviously difference in the peak shape and the width of peak isn't increase, and there are analogous responses on the whole when the injection qualities of sample are equally. Good linearity is obtained between different injection volume and its corresponding peak area, which correlation coefficient is above 0.99. This result indicates that transfer efficiencies of large volume injector are coincident in different injection volume.