Table 2.

Comparison of basic optical parameter characterization of commercially available reference materials. Information was collated using manufacturer websites and product sheets that were openly available. It is possible further is known about these products, but that information is not freely/openly available at the time of writing this review. Ticks depict whether information is provided by the manufacturer. Asterisks highlight measurement types that require a limit of detection to be provided. The last row shows if a limit of detection has been provided for any of the relevant measurements. SAXS; small angle x-ray scattering.