An assessment of common atmospheric particulate matter sampling and toxic metal analysis methods

Abstract

In this study, the atmospheric particulate matter (PM) was sampled using the tapered element oscillating microbalance, and the inductively coupled plasma mass spectroscopy (ICP-MS) and scanning electron microscopy coupled with energy dispersive spectrometry (SEM/EDS) were used for determination of elemental composition of the PM. The efficiency and relevance of the sampling method, ICP-MS and SEM/EDS in toxic metal analysis were assessed. Low flow rate yielded high accumulated mass of particulate matter. The efficiency of the filter media used was found to be, in decreasing order: teflon-coated glass fiber, ringed-teflon and quartz filters. The main elements identified from the SEM/EDS on ringed-teflon filters were Si, Fe, Mg, K, Na, C, S, F and O, and for ICPMS, the following main elements were identified: Fe, Al, Ca, Mg, K, Na, Cr, Ni, Pb, Cu, Zn and Mn. The ICP-MS proved to be more relevant for the analysis of the toxic metals of interest. The standard deviations obtained from this method were less than 30% for most of the metals identified. The method detection limit was also low (0.2 to 1 μg/L) for most metals, and 50% and less standard deviation to mean ratios were obtained for Ni and Pb.

Key words: Toxic metals, inductively coupled plasma mass spectroscopy, scanning electron microscopy coupled with energy dispersive spectrometry, particulate matter, tapered element oscillating microbalance.