New Method for Quantitative Analysis and Characterization of Platinum Nanoparticles in Road Dust

In a recent study, researchers at the University of Castilla-La Mancha in Toledo, Spain, have developed a new method for the quantitative analysis and characterization of platinum nanoparticles (PtNPs) in road dust. The study, published in the journal Spectrochimica Acta Part B: Atomic Spectroscopy, outlines a rapid sample preparation strategy using ultrasonic probe assisted extraction and single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) (1).

Car traveling through the desert, dusty road under the sun. | Image Credit: © puhimec - stock.adobe.com

PtNPs are widely used in vehicle catalytic converters, with an estimated global emission of 14.5 tons per year. Once emitted, they can accumulate in different environmental compartments, particularly in road dust, and pose a risk to the environment and human health. However, a lack of standardized analytical methods for the detection and quantification of PtNPs in these complex samples currently exists.

PtNPs are miniscule particles of platinum metal. The size of these particles typically ranges from less than 10–400 nanometers. They are engineered to possess unique physical and chemical properties, which make them useful in a wide range of applications, particularly in catalysis. PtNPs are widely used in the automotive industry as catalysts to reduce harmful emissions from vehicles. However, their increasing use has also raised concerns about their potential impact on human health and the environment.

To address this challenge, the researchers optimized critical parameters in the extraction and phase separation steps of the method, using a road dust reference material (BCR-723) and spiked road dust samples. The final method involves sonication probe assisted extraction using water as the extractant, followed by centrifugation-based separation and dilution before SP-ICP-MS analysis.

The researchers tested the applicability of their method by analyzing real road dust samples, with PtNP sizes ranging from 15 to 75 nm and concentrations from 6.0 to 20.0 ng/g. They found that PtNPs represented from 11 to 27% of the Pt content in the samples.

The method developed in this study provides information about PtNP size and both mass- and particle-based concentration in less than 11 minutes. The researchers achieved a recovery rate of 100±1% in spiked road dust samples, and a 12±1% (n = 6) of the total Pt was found to be in the form of PtNPs in the certified reference material.

The development of this new method is a significant step forward in the detection and quantification of PtNPs in road dust, and can contribute to more comprehensive environmental risk assessments.

Reference

(1) Sánchez-Cachero, A.; Rodríguez Fariñas, N.; Jiménez-Moreno, M.; Rodríguez Martín-Doimeadios, R. C. Quantitative analysis and characterization of PtNPs in road dust based on ultrasonic probe assisted extraction and single particle inductively coupled plasma mass spectrometry. Spectrochim Acta Part B At Spectrosc. 2023, 203, 106665. DOI: 10.1016/j.sab.2023.106665