How to Measure TiO2 Engineered Particle Concentrations in Surface Waters

Sewage spills are a key source of titanium dioxide engineered (nano)-particles found in the environment.

6.1 million metric tons of TiO₂ engineered nano- and micro-particles were consumed in 2016. They are utilized in sun blocks, cosmetics, food, paper, plastic, coatings, paints and in a variety of other products.

Toxicity of TiO₂ Engineered Nanoparticles

The toxicity of TiO₂ engineered nanoparticles has been evidenced in various studies. For example, engineered nanomaterials (ENM) were found to induce inflammatory, cytotoxic, and genotoxic effects, along with causing oxidative stress.

As such, ENM must be rigorously controlled in order to reduce human exposure. The necessary exposure assessment can be made challenging by a lack of appropriate analytical tools to quantitatively detect engineered nanomaterials in complicated natural environments.

Predicted no effect concentrations (PNEC) for ENM are founded on theoretical fate models, with unsubstantial experimental data to support their efficacy. These theoretical models do not include points of discharge of nanomaterials into the environment, also known as ‘hot spots’, the inclusion of which would help to validate and parameterize them more effectively.

Multi-Element Single Particle Inductively Coupled Plasma Mass Spectrometry

In this study, the authors utilize multi-element single particle inductively coupled plasma mass spectrometry (ME-sp-ICP-MS) performed on a TOFWERK icpTOF mass spectrometer to identify and measure the amount of engineered TiO₂ particles released in sanitary sewer overflow spills.

Many techniques are applied in this complex study to measure the fraction of engineered released TiO₂ particles in the high background of natural Ti-containing particles

Differentiatiating Engineered TiO₂ from Natural Ti-Containing Particles

With its ability to simultaneously detect particles, the icpTOF enables the differentiation of engineered TiO₂ from natural Ti-containing particles founded on the elemental fingerprinting of individual particles.

ME-sp-ICP-MS helps to detect Nb as a dependable tracer for natural particles which in turn is utilized to find the total concentration of TiO₂ engineered particles by bulk techniques. However, it does not give reliable quantitative results on particle number concentration as it is unable to detect TiO₂ particles < 40 nm (detection limit).

Aside from engineered particles, the icpTOF allows for the study of natural minerals on a minute scale. In a study of river samples, elemental ratios of Ti to a variety of other elements in individual particles were in alignment with the average riverine particulate and/or crustal material element ratios.

“This is the first time, to the best of our knowledge, that these elemental associations and ratios of Ti to natural elemental tracers have been identified and quantified on an individual particle basis. These findings are indicative of the considerable advantages offered by ME-SP-ICP-MS in identifying natural tracers of natural particles, which will be extended to other types of particles in the future.”

Environmental Science: Nano

DOI: 10.1039/c8en01376d

Produced from materials originally authored by Loosli, F.; Wang, J.; Rothenberg, S.;  Bizimis, M.; Winkler, C.; Borovinskaya, O.; Flamigni, L. and Baalousha, M. from TOFWERK

This information has been sourced, reviewed and adapted from materials provided by TOFWERK.

For more information on this source, please visit TOFWERK.