Sputtered alumina as a novel stationary phase for micro machined gas chromatography columns

Silica and graphite sputtering have previously been reported as novel solid stationary phase deposition techniques for micro gas chromatography columns. As a conventional solid stationary phase in gas chromatography, compatible with sputtering yet so far unreported, alumina was evaluated in this study. Alumina sputtered semi-packed micro columns were fabricated (including an activation step) and proved able to separate a mixture of volatile alkanes (C-1-C-4 with isomers) in less than 1 min. Kinetic and a thermodynamic evaluation led to calculation of 4,500 theoretical plates for ethane in 1.1 m (HETPmin = 250 mu m) and a Gibbs free energy for propane of 30.2 kJ mol(-1), making this stationary phase's properties very close to those observed with silica-sputtered micro columns.