Dynamic light-scattering measurement comparability of nanomaterial suspensions

Abstract

Increased use of nanomaterials in everyday products leads to their environmental release and therefore, the information need on their fate and behaviour. Nanomaterials have to be suspended with high repeatability and comparability for studies on environmental effects. They also have to be well characterised with a focus on the state of agglomeration and particle size distribution. Dynamic lightscattering (DLS) is a common technique used for these measurements. If suspensions are prepared in different laboratories, then concern has risen about the comparability of the measured results, especially when different DLS instruments are used. Therefore, for quality assurance, a round-robin test was conducted to assess the comparability of different DLS instruments and a dispersion protocol in ten independent laboratories. Polystyrene and TiO2 were chosen as test (nano)materials. For the comparability of the DLS instruments, the average sizes of the PSL and a stabilised TiO2 suspension were measured. The measured average hydrodynamic diameter shows an overall good inter-laboratory comparability. For the PSL suspension, an average hydrodynamic diameter of 201 ± 13 nm and for the TiO2 suspension an average diameter of 224 ± 24 nm were detected. For the TiO2 suspension that was prepared at each laboratory following an established suspension preparation protocol, an average hydrodynamic diameter of 211 ± 11 nm was detected. The measured average particle size (mode) increased up to 284 nm with a high standard deviation of 119 nm if the preparation protocol could not established and different procedures or different equipment were employed. This study shows that no significant differences between the employed DLS instrument types were determined. It was also shown that comparable measurements and suspension preparation could be achieved if welldefined suspension preparation protocols and comparable equipment can be used

Characterizing the binding interaction between ultrafine carbon black (UFCB) and catalase: electron microscopy and spectroscopic analysis

“…S2 †), an indication for a mildly polydisperse suspension. 24 The suspension obtained from 0.8 mm lter suggested the existence of particles with both number and volume peak sizes at about 100 nm. Aer the ltration of 0.22 mm lter, much smaller particles with number and volume peak sizes (25 nm) were detected in the ltrate.…”

“…The latter two groups were used to detect smaller particles that might exist in the FW200 suspension since larger particles can overshadow the smaller particles. 24 In Fig. 2, the DLS analysis conducted on the raw FW200 system yielded a diameter of 180 nm for number-size-distribution and 220 nm for volume-size-distribution, which suggested that the particles in T80 solution agglomerated highly.…”

Progress and future of in vitro models to study translocation of nanoparticles

“…Widely used methods to detect nanoparticles in liquid dispersions are dynamic light scattering (DLS), centrifugal liquid sedimentation (CLS) (Braun et al 2011 ; Cascio et al 2015 ; Murdock et al 2008 ; Nickel et al 2014 ; Powers et al 2006 ) and nanoparticle tracking analysis (NTA) (Filipe et al 2010 ; Vasco et al 2010 ). These methods allow determining an average size or size distribution related to the measured intensity signal.…”

Non-equivalence of different evaluation algorithms to derive mean particle size from dynamic light scattering data

“…Wang et al 2007;Tuoriniemi et al 2014), only a reference to DLS is made without additional information on the evaluation algorithm. Nickel and colleagues compared the results of different DLS instruments on various nanomaterial suspensions and found no significant differences between instruments (Nickel et al 2014). However, eight participants in their study used the Malvern Zetasizer Nano ZS, and only two other instruments were used.…”