3D-Printed Metal Column Developed for Micro-GC

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Micro-gas chromatographic (μGC) systems have evolved considerably since the first chromatographic gas analyzer was fabricated on a silicon wafer in 1979 (2). While this progress has brought significant improvements a number of issues still exist with the most critical part of the μGC system—the microfabricated separation column (μcolumn). The multi‑step process to produce μcolumns is fraught with potential issues from the mismatched thermal expansion coefficients of different materials to issues regarding reproducibility and consistency. The result is an expensive and time-consuming production process with many potential pitfalls.

3D-printing technology has the potential to overcome many of the issues with μcolumns because it offers freedom of design, complex geometry with high precision, the elimination of tooling, rapid prototyping, reduced fabrication times, and cost‑effective customization (3,4). Furthermore, the printing substrates have the potential for ingenuity.

Utilizing this technology, researchers designed and produced a μcolumn using Ti6Al4V Grade 23 powder and a direct metal laser sintering (DMSL). DMSL is a widely used 3D-printing technique where metal powders on the platform are selectively sintered together by a high powered laser. The column was then coated with a stationary phase, characterized, and used in a GC analysis.

Results of the column characterization found the 500-μm-diameter circular channel and 800 μm-wide ports to be uniform and without distortion when examined with 3D X-ray microscopy. Furthermore, the columns displayed physical and thermal properties similar to that of standard Ti6Al4V Grade 23 alloy with near zero porosity (~0.07%).

The column was tested with pre-treatment and stationary coating, as well as with no treatments and only with pre‑treatment. A superior separation was achieved with the column with both pre-treatment and stationary coating when a gas mixture of alkanes aromatics, alcohols, and ketones was investigated. Researchers then employed the column to separate a gas mixture of 12 alkanes with the results showing no significant column or peak tailing.

Following these results the researchers anticipate that the technology can lead to further advancements of μGC technology and further deliver the promised reduction of analysis times, resources, sample quantity required, and costs.