An all-silicon microfabricated gas chromatographic column with a high aspect ratio.

Increasing the aspect ratio of the microchannels of microfabricated gas chromatographic columns (μGCCs) can allow analytes to quickly reach equilibrium between the stationary phase and mobile phase, which helps improve their separation performance. In this paper, an all-silicon microfabricated gas chromatographic column (AS-μGCC) with a high aspect ratio was proposed and fabricated using deep reactive-ion etching (DRIE) and silicon direct bonding. Two AS-μGCCs with the lengths of 2 m and the aspect ratios of 6.6 (100 µm-width × 660 µm-depth) and 25 (30 µm-width × 750 µm-depth) were successfully fabricated. The effects of different aspect ratios on the column efficiency of AS-μGCCs were studied. A separation experiment showed that the column efficiency of the AS-μGCC with an aspect ratio of 25 (AS-μGCC-25) was 12 times higher than that of the AS-μGCC with an aspect ratio of 6.6 (AS-μGCC-6.6). The column efficiency of the AS-μGCC-25 was 1961 plates/m, and a heavy hydrocarbon mixture (C8–C20) could be separated using AS-μGCC-25 within 4.5 min [Display omitted] • Two all-silicon microfabricated gas chromatographic columns with aspect ratios of 25 and 6.6 were fabricated. • The AS-μGCC-25 showed a 12-fold improvement in the column efficiency as compared to the AS-μGCC-6.6. • By optimizing the conditions of the temperature programming, C8–C20 could be separated using AS-μGCC-25 within 4.5 min. [ABSTRACT FROM AUTHOR]