Reidy Shaelah, Lambertus Gordon, Reece Jennifer, Sacks Richard
Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
Anal Chem. 2006 Apr 15;78(8):2623-30. doi: 10.1021/ac051846u.
A procedure is described for the preparation of high-performance etched silicon columns for gas chromatography. Rectangular channels, 150 mum wide by 240 mum deep are fabricated in silicon substrates by gas-phase reactive ion etching. A 0.1-0.2-mum-thick film of dimethyl polysiloxane stationary phase is deposited on the channel walls by filling the channel with a dilute solution in 1:1 n-pentane and dichloromethane and pumping away the solvent. A thermally activated cross-linking agent is used for in situ cross-linking. A 3-m-long microfabricated column generated approximately 12 500 theoretical plates at optimal operating conditions using air as carrier gas. A kinetic model for the efficiency of rectangular cross-section columns is used to evaluate column performance. Results indicate an additional source of gas-phase dispersion beyond longitudinal diffusion and nonequilibrium effects, probably resulting from numerous turns in the gas flow path through the channel. The columns are thermally stable to at least 180 degrees C using air carrier gas. Temperature programming is demonstrated for the boiling point range from n-C5 to n-C12. A 3.0-m-long column heated at 10 degrees C/min obtains a peak capacity of over 100 peaks with a resolution of 1.18 and a separation time of approximately 500 s. With a 0.25-m-long column heated at 30 degrees C/min, a peak capacity of 28 peaks is obtained with a separation time of 150 s. Applications are shown for the analysis of air-phase petroleum hydrocarbons and the high-speed analysis of chemical warfare agent and explosive markers.
描述了一种用于制备气相色谱用高性能蚀刻硅柱的方法。通过气相反应离子蚀刻在硅基片上制造出宽150μm、深240μm的矩形通道。通过用1:1正戊烷和二氯甲烷的稀溶液填充通道并抽走溶剂，在通道壁上沉积一层0.1 - 0.2μm厚的二甲基聚硅氧烷固定相薄膜。使用热活化交联剂进行原位交联。一根3m长的微制造柱在以空气作为载气的最佳操作条件下产生了约12500个理论塔板。使用矩形横截面柱效率的动力学模型来评估柱性能。结果表明，除了纵向扩散和非平衡效应外，还有一个气相扩散的额外来源，这可能是由于气流通过通道的路径中有许多转折所致。使用空气载气时，这些柱在至少180℃的温度下是热稳定的。展示了对正戊烷到正十二烷沸点范围的程序升温。一根3.0m长的柱以10℃/min的速率加热，获得了超过100个峰的峰容量，分辨率为1.18，分离时间约为500s。对于一根0.25m长的柱，以30℃/min的速率加热，获得了28个峰的峰容量，分离时间为150s。展示了其在分析气相石油烃以及化学战剂和爆炸物标记物的高速分析中的应用。
