A micro gas chromatographic column with in-situ growing macro-porous silicon as stationary phase support layer

This paper reports a micro gas chromatographic column (μGCC) with in-situ growing macro-porous silicon as the stationary phase support layer. The macro-porous silicon stationary phase support layer (MPSL) with uniform thickness was fabricated in-situ on the inner surface of the μGCC channels by metal-assisted chemical etching. In order to avoid the negative effect of uneven thickness of the stationary phase, a 10 nm alumina film was deposited as the stationary phase on the MPSL using the atomic layer deposition technique. The macro-porous structure and high specific surface area of the MPSL provide longer diffusion paths and larger mass transfer interfaces for the analytes, which reduces the longitudinal gas diffusion and mass transfer resistance, thus improving the column efficiency. The μGCC with the MPSL achieved a 1306.7% increase in the theoretical plate number and a 195.0 % improvement in the resolution for n-nonane compared with the μGCC without the MPSL.