| Bionanomaterials, and other nanoparticles, are used extensively in biomedical and industrial research and applications. Particle size is a primary characteristic of nanomaterials, and must be assessed correctly and efficiently. Though many definitions of nanoparticle set an upper size limit of about 100 nm, The Food and Drug Administration (FDA) has yet to define how nanomaterials shall be defined for regulatory purposes. The emulsions discussed herein extend beyond 100 nm, but accurate characterization of their size is of upmost importance.;Dynamic Light Scattering (DLS) can be used to quickly determine the size distribution of a large quantity of particles, measuring them in situ. ASTM E 2490-09 includes the results of a large interlaboratory study focused on determining the accuracy of DLS in the ∼5 -- 60 nm range; however, accuracy data for DLS on larger particles are limited. In this thesis, the accuracy (trueness and precision) of the Malvern Instruments ZetasizerNano ZS (Zetasizer) DLS device was assessed by means of Gauge R & R for polystyrene nanospheres in the size ranges of 60 nm, 450 nm, and 900 nm. The nanospheres were tested both separately and in heterogeneous mixtures. Each of the four outputs (Z-ave, Intensity, Number, and Volume) of the Zetasizer was compared in each case.;Each output yielded slightly different accuracy, but for the Z-ave for the homogeneous samples, the results were 63.7 nm +/- 1.0% (59 +/- 2.5 nm nominal), 464.7 nm +/- 2.7% (453 +/- 9 nm nominal), and 940.2 nm +/- 4.3% (903 +/- 12 nm nominal). Typically, precision was greater for smaller particles, while trueness increased with particle size.;It was shown that separate measurements performed under different automatic optimizations were preferred to multiple measurements within one automatic optimization. Also, the combination of all four outputs was of no general benefit and is not advised.;Testing on the emulsion included repeatability testing, followed by additional extrusion and sonication to address poor sample quality. The emulsion testing was about two to three times less repeatable than the mixed standard samples. Additional extrusion was shown to benefit the emulsion, while sonication had relatively low impact on particle size and sample quality. |
