Table 4.
MOF characterization techniques.
| Technique | Property |
|---|---|
| Powder/single-crystal X-ray diffraction (XRD) | Crystallinity: crystal structure, crystalline parameters |
| Small- and wide-angle scattering (SAXS/WAXS) | Monitor the crystallization of MOFs |
| X-ray photoelectron spectroscopy (XPS) | Surface characterization: electronic structure, oxidation states, elemental composition, coating material binding |
| X-ray absorption spectroscopy (XAS) | Element-specifical investigation of chemical state and interatomic distances of species |
| Energy dispersive X-ray spectroscopy/spectroscopy (EDX/EDS) | Quantitatively determine elemental composition of MOFs |
| Porosimetry | Porosity: BET surface area and deep insight of pore size, volume and distribution of MOFs |
| Scanning electron microscopy (SEM) | Size and morphology |
| Transmission electron microscopy (TEM) | Size and morphology |
| Scanning transmission electron microscope (STEM) | Combined with high-angle annular dark field (HAADF) detector and EDX for investigation of morphology, elemental composition, and crystal structure |
| Raman microscopy | Homogeneity on composition and morphology |
| Atomic force microscope (AFM) | Size and shape in 3D mode, evaluate surface modification, localization of MOFs in cells or other matrices |
| Dynamic light scattering (DLS) | Hydrodynamic diameter |
| Nanoparticle tracking analysis (NTA) | Hydrodynamic diameter, particle concentration, individual particle tracking |
| Zeta potential | Surface charge |
| Fourier-transform infrared spectroscopy (FT-IR) | MOF degradation, drug loading, surface modification, structural defects |
| Ultrafast 2D IR spectroscopy | Structural dynamics inside a functionalized MOF |
| Nuclear magnetic resonance spectroscopy (NMR) | Interaction between the drug and MOF crystals, the precise drug localization, as well as catechizing the metal center and probing the linker molecules |
| Mössbauer spectroscopy | Investigation of chemical environment of Mössbauer nuclei (such as Fe atoms) in the sample, including the oxidation state, surface spins, and symmetry, etc. |
| Ultraviolet–visible spectroscopy (UV–Vis) | Optical properties, size, concentration |
| Inductively coupled plasma mass spectrometry (ICP-MS) | Elemental composition, intracellular MOFs quantification |
| Thermogravimetric analysis (TGA) | Thermal decomposition of MOFs |