A semi-packed gas chromatographic column with staggered elliptic cylindrical post arrays.

A semi-packed gas chromatographic column has the advantages of high specific surface area and low column pressure. We report that the stagnation regions formed in the adjacent posts along the channel of the semi-packed columns can decrease the area and height of chromatographic peaks, which makes it difficult to detect low-concentration mixed gases. A semi-packed column with staggered elliptic cylindrical post arrays (SC-S) made using a micro-electro-mechanical system technique is presented, and the separation performance of SC-S is compared with that of a semi-packed column with aligned elliptic cylindrical post arrays (SC-A). The simulation results show that the width of stagnation regions in SC-S is 86.89% smaller than that in SC-A. The experimental results indicate that the area and height of chromatographic peaks increased as stagnation regions reduced. In the separation of the alkane mixture from C8 through C10 with 10 ppm concentration, the chromatographic peak of decane was hardly identified in SC-A while the chromatographic peak in SC-S was still clearly visible. The chromatographic peak heights of octane and nonane were increased by 65.06% and 130.00%, respectively, in SC-S. The peak areas of octane and nonane were increased by 120.45% and 168.18%, respectively.