Number Concentrations For Nanoparticles

Nanoparticles (NPs) are an essential building block for the development of new materials with improved properties, e.g. optical, thermal or mechanical.[1] Parameters such as the particle size, shape and concentration must be carefully controlled to comply with performance, cost and safety requirements. SAXS is a well-established technique for traceable size measurements.[2,3,4] Recently, it was also shown that number concentrations of NPs could be reliably determined from SAXS data collected at synchrotron facilities with metrological traceability to the standard system of units (SI).[5] We demonstrate in this Application Note that traceable number concentrations can also be obtained using a SAXS laboratory setup with acquisition times of 10 min. […]

A certified concentration standard from LGC (colloidal dispersions of citrate-stabilized gold NPs, modal diameter 30.7 nm, number concentration 1.47E11±2.8E10 particles per mL, product code LGCQC5050)[6] has been measured as-received and in dilution series. The measurements were done on a Nano-inXider instrument in a flowcell, whose thickness was determined from the transmission value. […]

Figure: Colloidal dispersion of gold NPs with certified concentration measured as received and in dilution series. Relative number concentration determined from the SAXS profile as a function of the relative dilution determined gravimetrically when preparing the dilution.

References:

[1] S. Logothetidis, Nanostructured Materials and Their Applications, Springer, 2012.

[2] G. Gleber, L. Cibik, S. Haas, A. Hoell, P. Müller and M. Krumrey, “Traceable size determination of PMMA nanoparticles based on Small Angle X-ray Scattering (SAXS),” Journal of Physics: Conference Series, vol. 247, p. 012027, 2010.

[3] F. Meli, T. Klain, E. Buhr, C. G. Frase, G. Gleber, M. Krumrey, A. Duta, S. Duta, V. Korpelainen and R. Bellotti, “Traceable size determination of nanoparticles, a comparison among European metrology institutes,” Measurement Science and Technology, vol. 23, p. 125005, 2012.

[4] B. Pauw, C. Kästner and A. Thünemann, “Nanoparticle size distribution quantification: results of a small-angle X-ray scattering inter-laboratory comparison.,” Journal of Applied Crystallography, vol. 50, pp. 1280-1288, 2017.

[5] A. Schavkan, C. Gollwitzer, R. Garcia-Diez, M. Krumrey, C. Minelli, D. Bartczak, S. Cuello-Nuñez, H. Goenaga-Infante, J. Rissler, E. Sjöström, G. B. Baur, K. Vasilatou and A. Shard, “Number Concentration of Gold Nanoparticles in Suspension: SAXS and spICPMS as Traceable Methods Compared to Laboratory Methods,” Nanomaterials, vol. 9, no. 4, p. 502, 2019.