High density semipacked separation columns with optimized atomic layer deposited phases

Abstract

This paper reports the development of a new class of high-performance microfabricated separation columns called high-density semi-packed columns (HDSPCs). These columns are realized by using a meter long and 145 µm-wide silicon microchannel design with embedded circular micropillars (15 µm diameters) and 5 µm post spacing (perpendicular to the gas flow). The HDSPCs are coated using our previously developed atomic layer deposition (ALD) based aluminium oxide and silane functionalized thin adsorben t film. Moreover, in this study we optimize both ALD deposition temperature (100 ° C, 150 °C, 250 ° C and 300 ° C) and film thickness (10 nm, 20 nm and 30 nm) using different chromatographic parameters (plate number, peak-to-peak resolution, and separation factor). Additionally, the thermodynamic characteristics of these silane functionalized/ALD films are also studied using Van't Hoff plots. These columns with optimized stationary phases are able to provide ≈8,000 effective plates/meter and

Sensors for Volatile Organic Compounds

“…The most critical component in μGC is the microfabricated column, which must be carefully designed to optimize the separation of analytes. Like conventional columns, μ-columns are strategically coated with a stationary phase to optimize the separation of vapor analytes, 384 but they are several orders of magnitude shorter, noncylindrical, and normally microfabricated on top of planar substrates using a chip-based configuration. 381 The separation efficiency of μ-columns depends on several factors including column geometry (e.g., cross-sectional area, shape, topology), stationary and mobile phases, operating temperatures, and flow rate.…”

Advancements in Microfabricated Gas Sensors and Microanalytical Tools for the Sensitive and Selective Detection of Odors

“…In addition, one of the most critical components in µGC is the microfabricated column. Similar to conventional devices, µ-columns are strategically coated with a stationary phase to force the separation of vapor analytes [ 227 ]. Nonetheless, compared to conventional capillary columns, µ-columns are several magnitudes shorter, noncylindrical, and normally microfabricated on top of planar substrates, using a chip-based configuration [ 228 ].…”

Micro Gas Chromatography: An Overview of Critical Components and Their Integration

“…54,118 Our group has been successful in the development of thin films of alumina by atomic layer deposition. 61,119,120 The alumina films have been prepared by the reaction of trimethylaluminum and water on the surface of silicon at high temperature (250−300 °C) prior to anodic bonding. The surface −OH groups of alumina can be deactivated by treating the column with a dilute solution of chloro(dimethyl)octadecylsilane after anodic bonding.…”

“…Carbon nanotubes, because of higher surface-to-volume ratio and thermal stability, have been investigated as a stationary phase in microcolumns. Carbon nanotubes have been grown at the bottom of the separation channel by chemical vapor deposition prior to bonding the silicon chip with glass, and these columns are shown to be useful for ultrafast separation of light alkanes and other simple mixtures. , Another solid-phase material that has been collectively and reproducibly deposited using the sputtering technique is silica, and these films have been used in rapid separation of light aliphatic hydrocarbons. , Figure depicts a chromatogram for the separation of a mixture 9 n -alkanes in less than 15 s using a 2.2 m long silica-sputtered microcolumn developed by Haudebourg et al In addition to silica, these researchers have also investigated sputtered graphite and alumina as a stationary phase for the separation of light alkanes. , Our group has been successful in the development of thin films of alumina by atomic layer deposition. ,, The alumina films have been prepared by the reaction of trimethylaluminum and water on the surface of silicon at high temperature (250–300 °C) prior to anodic bonding. The surface −OH groups of alumina can be deactivated by treating the column with a dilute solution of chloro­(dimethyl)­octadecylsilane after anodic bonding.…”