A stamped aluminium gas chromatographic column disk employing directly grown anodic aluminium oxide stationary phase for the separation of aromatic and chlorinated compounds

In this study, mesoporous anodic aluminium oxide (AAO) with moderate polarity was used as a GC stationary phase to demonstrate the applicability to various compound species. The fluidic channel measured 6 meters in length and had a cross-section area of 0.127 mm². The column disk measured 6.2 cm in diameter and was fabricated through a stamping process on an aluminium substrate. The AAO stationary phase was directly grown on the aluminium substrate through an anodization process using oxalic acid as the electrolyte. The pore size of the AAO stationary phase was approximately 50-70 nm, with film thicknesses ranging from 6-20 μm. AAO based on oxalic acid exhibited significantly reduced surface polarity, making it suitable for separating polarizable and slightly polar compounds. The theoretical plate number for benzene had reached 1800 plates per meter, and for n-butane, it had reached 2500 plates per meter. A complex mixture of 16 compounds spanning alkanes, olefins, aromatics, and chlorinated hydrocarbons was effectively separated in 8 minutes with the temperature programmed to 200 °C.