Multi-elemental analysis of particulate matter samples collected by a particle-into-liquid sampler

Abstract

Time-resolved elemental analysis of particulate matter (PM) helps in the reliable identification of specific source tracers and study of mixing dynamics in the lower atmosphere. In this study, a new flow system (FS) for the introduction of samples into the inductively coupled plasma mass spectrometry (ICP-MS) instrument, which consists of on-line filtration and acidification of samples collected by a particle-into-liquid sampler (PILS), was optimised. Through this system, the limits of detection and quantification were significantly reduced, compared to those of ICP-MS analysis of samples collected by a PILS after off-line filtration. This makes it possible to conduct multi-elemental analysis of the samples collected by the PILS without any pre-treatment. The optimised FS-ICP-MS system was directly coupled with a PILS in order to study the profiles of some selected indoor and outdoor sources of PM (cigarette smoking, incense burning, brushwood burning, pellet burning, and road dust resuspension). The application of the FS-ICP-MS system for off-line elemental analysis of samples collected by a PILS during spot events in indoor and outdoor environments allowed us to verify the suitability of this system for the time-resolved (10 min) analysis of PM. The results indicate a significant increase in the indoor concentrations of some toxic elements (such as, Cd, and Pb) during the cleaning operation of domestic biomass burning systems (pellet stoves and thermo-fireplaces). Similarly, increases in the concentration of these elements were also observed in the outdoor environment during spot events of agricultural waste combustion, an illegal activity frequently practiced in many rural areas.