Method development and inter-laboratory comparison about the determination of titanium from titanium dioxide nanoparticles in tissues by inductively coupled plasma mass spectrometry

Abstract

Nanosized titanium dioxide (TiO2) is one of the most interesting and valuable nanomaterials for the construction industry but also in health care applications, food, and consumer goods, e.g., cosmetics. Therefore, the properties associated with this material are described in detail. Despite its widespread use, the analytical determination and characterization of nanosized metal oxides is not as straightforward as the comparatively easy-to-detect metallic nanoparticles (e.g., silver or gold). This study presents the method development and the results of the determination of tissue titanium (Ti) levels after treatment of rats with the nanosized TiO2. Total Ti levels were chosen to evaluate the presence and distribution of TiO2 nanoparticles. A procedure consisting of incubation with a mixture of nitric acid (HNO3) and hydrofluoric acid (HF), and heating was developed to digest tissues and TiO2 nanomaterials in order to determine the total Ti content by inductively coupled plasma mass spectrometry (ICPMS). For the inter-laboratory comparison, altogether four laboratories analyzed the same samples upon digestion using the available ICPMS equipment. A major premise for any toxicokinetic study is the possibility to detect the chemical under investigation in biological samples (tissues). So, the study has to be performed with a dose high enough to allow for subsequent tissue level measurement of the chemical under investigation. On the other hand, dose of the chemical applied should not induce over toxicity in the animal as this may affect its absorption, distribution, metabolism, and excretion. To determine a non-toxic TiO2 dosage, an acute toxicity study in rats was performed, and the organs obtained were evaluated for the presence of Ti by ICPMS. Despite the differences in methodology and independent of the sample preparation and the ICPMS equipment used, the results obtained for samples with Ti concentrations >4 μg Ti/g tissue agreed well.

Tissue distribution and elimination after oral and intravenous administration of different titanium dioxide nanoparticles in rats

“…The tissue distribution of the TiO 2 nanomaterials administered to the animals was evaluated by determining the Ti content in blood and tissues at various time points after administration by High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS), as recently developed and described [39]. For the oral study, the livers were homogenized in 50 mL centrifuge tubes for ~30 sec./level 2 using an Ultra Turrax T25 Basic (IKA Labortechnik, Staufen, Germany).…”

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…The work of Krystek et al 141 is therefore, of personal interest. Nanosized TiO 2 is one of the most widely used nanomaterials in a wide range of industrial applications including construction, health care and consumer goods and, for this reason, there is considerable interest in the toxicokinetics of this material.…”

Detection, characterization and quantification of inorganic engineered nanomaterials: A review of techniques and methodological approaches for the analysis of complex samples

“…Working with inorganic ENMs, the simplest approach is based on the use of an atomic spectrometry technique (flame AAS, ET-AAS, ICP-OES or ICP-MS, depending on the concentration) for monitoring of a specific element, both for detection and total element quantification. This may be sufficient when tackling with scenario 2 studies, where control samples with no added ENMs are available for comparison [113]; however, with samples from scenarios 1 and 3, more elaborated approaches are necessary. Then, an atomic spectrometry technique in conjunction with an electron microscopy technique (ICP-MS and TEM, most often) is viewed as the basic tools for adequate detection, total mass quantification and characterization (size and shape).…”

“…size, aggregation). Thus the main applications of these techniques are oriented to get total element concentrations in a variety of samples that include bioaccumulation and biodistribution studies of ENMs [112,113]. These limitations are overcome by using these techniques in combination with some of the sample preparation methods described in section 2…”