New Study Evaluates 3D-Printed High-Hardness Die Steel Microchip GC Column

Researchers from the Chinese Academy of Sciences (CAS) in Dalian, China developed a new type of micro-gas chromatography (GC) column to circumvent manufacturing issues. A study evaluating this micro-GC column was published in the Journal of Chromatography A (1).

Gas chromatography (GC) is used in various applications in fields such as including petrochemical analysis, pesticide detection, environmental monitoring, and energy exploration. However, traditional GC is unsuitable for on-site real-time detection, due to its large size, high power consumption, and lengthy detection time. This has led to the miniaturization of GC systems becoming an important development direction in chromatography. The GC column is core to GC systems, so its design and functionality; however, traditional chromatography columns face challenges in miniaturization, as they typically require placement in a separate oven with temperature control for heating, limiting their flexibility in application.

gas chromatograph in a chemical laboratory, good daylight | Image Credit: © Александр Ивасенко - stock.adobe.com

Micro electro mechanical systems (MEMS) columns have helped resolve this issue. Referring to the technology used to create miniature devices with moving parts that range from 1–1000 µm, MEMS technology originates from silicon microelectronics and shares similarities in design and fabrication processes (2). Micro columns can incorporate micro-fabricated heaters on the back of a substrate, enabling temperature control of the chromatography column while separating mixtures in the channel. The silicon-glass bonding technique remains widely used in micro-GC due to silicon’s durability against chemicals and solvents, the existence of modifiable Si-OH groups for the stationary phase coating, and mature processing technology. However, mismatches in the thermal expansion coefficients (CTE), or the extents to which materials’ size and volume change with temperature, can cause micro columns to crack or break under rapid temperature programming (3). While there are workarounds in progress, silicon-based micro gas chromatography columns exhibit high brittleness under applied stress, and the fabrication process typically requires 5–6 steps, thereby rendering it both costly and time-consuming.

In this study, a 3D-printed metal column specifically made for micro-GC application was developed and the team conducted an in-depth characterization of its performance and gas separation capabilities. The microchip GC column was fabricated using direct metal laser sintering (DMLS) technology using die steel powder. DMLS is a 3D printing technique that creates layers of a part by aiming a laser at a powder bed at specific points, guided by a digitally produced CAD [computer-aided design] file) (3). The column incorporates a 3-meter-long circular spiral channel, possessing an internal diameter of 500 μm, and employs OV-1 as the stationary phase. To enable efficient heating, a ceramic plate was affixed to one side of the column. The overall assembly weighed 118 g, facilitating the flexible adjustment of column length, thereby enhancing the analysis of complex mixtures.

The column displayed outstanding separation capabilities across mixtures encompassing ketones, aromatics, alkanes, and alcohols, demonstrating consistent repeatability. Notably, it enabled rapid temperature programming at an impressive rate of 120 °C/min within the boiling point spectrum spanning of C6 to C18, while maintaining its superior separation performance. Additionally, the design achieved success in separating benzene toluene ethylbenzene & xylene (BTEX), volatile organic compounds (VOCs), and gasoline, displaying its efficiency.

This new column could present a potentially solution to the challenges that currently exist with microchip columns. It could also provide new insight into how to optimize column length through the construction of large-curvature channels on a constrained planar substrate. Additionally, per the scientists’ sentiments, the design freedom of the GC channel could be determined by the stability of the material, instead of the fabrication process.

References

(1) Wei, Y.; Meng, H.; Feng, L. A 3D-Printed High-Hardness Die Steel Microchip GC Column: 3-Meter Long, Low-Cost, and Exhibiting Superior Separation Performance. J. Chromatogr. A 2025, 1748, 465842. DOI: 10.1016/j.chroma.2025.465842

(2) Microelectromechanical System. ScienceDirect 2006. https://www.sciencedirect.com/topics/physics-and-astronomy/microelectromechanical-system (accessed 2025-3-20)

(3) What is Direct Metal Laser Sintering (DMLS)? Markforged 2025. https://markforged.com/resources/learn/3d-printing-basics/3d-printing-processes/what-is-direct-metal-laser-sintering-dmls (accessed 2025-3-20)