Advancing Fluid Characterization for Energy and Environmental Research with ETHOS system

The Technical University of Denmark (DTU) is one of Europe’s leading engineering universities, recognized for its strong integration of research, education, and industrial collaboration. DTU maintains a distinctive DNA rooted in close partnerships with industry, ensuring that scientific advancements translate into practical and societal impact. DTU Offshore is a specialized department within the university that focuses on offshore and subsurface environments. Historically characterized by strong collaboration with North Sea offshore industries, the department has evolved in recent years toward a broader research portfolio while maintaining deep industrial engagement. Its activities span offshore energy systems, including geothermal and wind energy, hydrogen, and carbon storage, alongside environmental impact assessment and subsurface modeling. Within this framework, the Fluid Characterization Laboratory plays a critical role in supporting both research and industry-facing projects through advanced analytical investigations of complex subsurface-derived samples.

Two primary technical challenges were identified:

1. High carbon content and biological materials, which can complicate digestion and interfere with inorganic analysis.
2. Heterogeneous samples composed of different matrices, particularly in environmental projects, may lead to incomplete digestion and consequently to an underestimation of elemental content.

Before microwave technology was introduced, digestion was performed using traditional hot-plate methods. This approach presented several limitations:

1. Lower digestion efficiency due to reduced temperature and absence of pressure.
2. Greater exposure to acid fumes of the operators.
3. Higher contamination risk from the external environment
4. Extensive manual handling and longer processing times.
5. Difficulty achieving true total digestion, particularly for heterogeneous samples.

For environmental investigations, where complete digestion is essential to avoid underestimating metal content, these limitations became challenging.

To overcome these constraints, the laboratory implemented the Milestone ETHOS EASY microwave digestion system in 2022.
The decision was justified based on key technical advantages:

• Closed-vessel digestion, improving digestion quality and safety, by obtaining complete digestion and less exposure to acid fumes.
• High power capability, enabling fast and simultaneous digestion of complex and organic-rich matrices.
• Accurate temperature monitoring, using a contactless temperature sensor for accurate control of the digestion conditions in all vessels.

The adoption of microwave digestion transformed sample preparation from a complex and safety-concerned process into a controlled, reproducible, and efficient workflow. The ability to achieve high temperatures under pressure significantly enhanced digestion efficiency, particularly for heterogeneous and particulate-containing samples. Equally important, ETHOS microwave digestion system reduced exposure to acid fumes and minimized external contamination risks, directly improving laboratory safety and data reliability.