Optimization of Sample Preparation in the Study of Urban Dust Nanoparticles by Single Particle Inductively Coupled Plasma Mass Spectrometry

Abstract

Urban dust nanoparticles, which are extremely mobile in the environment and easily penetrate into living organisms, are important samples of ecoanalytical research. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is an effective method for studying anthropogenic nanoparticles. A critical step in an SP-ICP-MS analysis of environmental nanoparticles is sample preparation, which typically involves the preparation of suspensions and the extraction of nanoparticles from a polydisperse sample. This paper shows that the optimal ratio of dust sample to the extractant (water) for the separation of nanoparticles by centrifugation is 1 : 500. It was found that, for a study, it is advisable to take a 20-mg dust sample in 10 mL of water, at which the time spent for the extraction of nanoparticles is reduced and their mass concentrations can be determined with an average relative standard deviation no more than 34%. Using a standard sample of gold nanoparticles, the completeness of the extraction of nanoparticles from a polydisperse dust sample was estimated at 102 ± 4%. The optimized sample preparation method was tested using samples of urban dust from the city of Krasnoyarsk; the mass concentrations and median diameter of Cr-, Cu-, Zn-, Sn-, Sb-, W-, Pb-, and Bi-containing nanoparticles were determined.