CHNS-O DETERMINATION IN METAL ORGANIC FRAMEWORKS BY FLASH COMBUSTION

Metal-Organic Frameworks (MOFs) are unique crystalline materials consisting of metal ions or clusters coordinated with rigid organic ligands to form one-, two- or three-dimensional structures with very high porosity.

They are generally applied to design systems with highly specific properties. In particular, the internal surface, formed by pores, can be adapted to specific applications by adjusting the surface-area-to-volume ratio. For this reason, nowadays, the interest of many scientists is moving towards their optimization for industrial applications: gas storage and separation, sensors, water and soil purification, biomedicine, microelectronics, etc.

In this context, our Analytical Department tested 7 MOFs with expected values of:

• Carbon (C): ~55%
• Hydrogen (H): ~7%
• Nitrogen (N): ~10%
• Oxygen (O): ~20%
• The compounds do not contain Sulfur (S)

The MOFs appear as fine, highly electrostatic powders. For this reason, proper sample preparation is crucial in order to obtain accurate and reproducible results. In this regard, samples were preheated, placed in a desiccator, and carefully weighted using a micro-balance.

The complete analysis has been carried out in two different steps:

• CHNS configuration with a specific calibration curve created to determine the concentration of Carbon, Hydrogen, and Nitrogen in samples;
• O configuration with a specific calibration curve created to determine the concentration of Oxygen in samples.

The results, obtained by our specialists using the EMA 502 Elemental Analyzer, are in line with the expected values. High accuracy and reproducibility are granted by the TCD detection technology, with a LOD of 0.001 mgN (with Helium) and an RSD of 0.2% (Sulphanilic acid). 

Read the application note to learn about official methods, analytical procedures, steps of the analysis, safety precautions, and how to get accurate results for the CHNS-O determination in MOFs by using the VELP EMA 502 Elemental Analyzer.
 

DOWNLOAD THE APPLICATION NOTE