Article ID Journal Published Year Pages File Type
750600 Sensors and Actuators B: Chemical 2015 9 Pages PDF
Abstract

•An improved alkane thiol based stationary phase coating process presented for semipacked columns.•Kinetic and thermodynamic properties of functionalized evaporated gold and nanoparticles films studied.•Semipacked columns are utilized to achieve a high speed separation of high boilers within 45 s.

Semipacked columns (SPCs) with integrated micropillars have been characterized for high chromatographic efficiencies and fast separations. In this article, high-yield and stable alkane thiol based stationary phase coating methods are presented for SPCs. Briefly, a new three step (anisotropic, O2 plasma, and isotropic) etching method is first developed in order to improve metal lift-off by producing a 3-dimensional undercutting profile inside deep etched SPCs. This innovative fabrication scheme is used for 1 m-long, 220 μm-deep, 190 μm-wide SPCs with circular micropillars of 20 μm-diameters and 42 μm-post spacing. Two different thin gold film deposition techniques are utilized for microcolumns (1) a wafer-level physical vapor deposition, and (2) a device level layer-by-layer (LbL) self-assembly of gold nanoparticles (3.2 nm diameter). After gold film deposition and metal lift-off, the surface of the patterned gold layer is functionalized with a 2 mM octadecanethiol (C18H37SH) solution for chromatographic separations. Both kinetic (Golay plots) and thermodynamic (Van’t Hoff plot) properties of thiol-functionalized gold phases are studied. The significance of SPCs, for faster analysis, is also validated by achieving baseline separation of a straight chain alkane mixture, containing high boilers (174 °C to 287 °C), within 45 s.

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Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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