Table 2.

Overview of characterization of ENMs. While class 1 properties are intrinsic to a nanomaterial itself, the class 2 properties are dependent on the interplay between ENM and assay system.

Nanomaterial property	Available analytical techniques
Class 1: “As-produced” -morphology and structure
Primary particle size, shape, and size distribution	TEM, SEM, AFM, ESEM, FIB-SEM, cryo-TEM
Fractal structure	TEM, SAXS, SANS
Pore size, porosity, and surface area	BET, SAXS, SANS
Crystallinity, framework structure, and crystal size	XRD, Raman, SAXS, NMR
Chemical composition	Raman, NMR, EDAX, FTIR, XPS, ICP
Elemental speciation and redox state	Raman, XAFS, XANES, NMR
Electronic, magnetic, and photonic properties	SAXS, Mossbauer, ESR, Raman, UV-Vis
“Dustiness” or tendency to aerosolize	EMPS, SMPS
Class 2: “As Dispersed” - interfacial properties
Dispersed size and size distribution	DLS, EMPS, SMPS, laser diffraction
Aggregate size	DLS, electro-acoustics
Charge density, pKa, PZC, ionization fraction	Direct titration in various suspending media
Surface (zeta) potential and IEP	EPM measurements in various suspending media
Surface tension components (LW, γ +, γ −)	Multiple probe liquid contact angle measurment
Roughness and chemical heterogeneity	AFM, CFM, FTIR, XPS, NMR, Raman