Title :
Semipacked separation columns with monolayer protected gold stationary phases for microgas chromatography
Author :
Shakeel, H. ; Agah, Masoud
Author_Institution :
Bradley Dept. of Electr. & Comput. Eng., VT MEMS Lab., Blacksburg, VA, USA
Abstract :
Semi-packed columns (SPC), as a new class of gas chromatography columns, offer several advantages like increased surface area and sample capacity compared to open columns and the elimination of the differential flows observed in multicapillary columns. We present herein for the first time SPCs with monolayer protected gold stationary phases by utilizing the ability of octadecanethiol (C18H37SH) to self-assemble on deposited gold layers. We employed two selective gold deposition approaches followed by thiol functionalization; 1) our previously reported high-yield double-doped self-patterned process and 2) e-beam evaporation of gold followed by the lift-off process. By utilizing both schemes, we produced 1m-long, 250μm-deep, 190μm-wide semipacked columns with circular micropillars of 20 μm-diameters and 20 μm-post spacing. Both approaches afford the separation of complex gas mixtures with wide range of boiling points. However, the shadowing effect inherent in e-beam evaporation specifically for high-aspect-ratio structures results in incomplete gold coverage and limits its application in separation columns with microposts.
Keywords :
boiling point; chromatography; doping; electron beam deposition; gas mixtures; gold; monolayers; organic compounds; self-assembly; vacuum deposition; Au; SPC; boiling point; circular micropillar; complex gas mixture; doped self-patterned process; e-beam evaporation; gold deposition approach; lift off process; microgas chromatography; monolayer protected gold stationary phase; multicapillary column; octadecanethiol; self-assembly; semipacked separation column; shadowing effect; size 1 m; size 190 mum; size 20 mum; size 250 mum; thiol functionalization; Chemical sensors; Fabrication; Gas chromatography; Gold; Sensors; Surface treatment; USA Councils;
Conference_Titel :
Sensors, 2012 IEEE
Conference_Location :
Taipei
Print_ISBN :
978-1-4577-1766-6
Electronic_ISBN :
1930-0395
DOI :
10.1109/ICSENS.2012.6411352