Multi-element analysis of airborne particulate matter collected on PTFE-membrane filters by laser ablation inductively coupled plasma mass spectrometry

Abstract

Direct analysis of airborne particulate matter collected on PTFE-membrane filters using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was performed. Laboratory prepared standard filter samples were analyzed. Several parameters, including the laser energy, pulse type and beam focus, thermal properties and homogeneity of the sample and the carrier gas flow rate, may affect the LA-ICP-MS measurement. The influences of these parameters were thoroughly examined. Empirical results obtained here demonstrated that applying LA-ICP-MS for multi-element analysis of airborne particulate matter collected on PTFE-membrane filter is feasible. More than 20 major, minor and trace elements in airborne particles on PTFE membrane filters can be determined. It was found that the optimum ablation efficiency can be achieved using a 160 mJ single shot laser operated in the free-running mode with a 6.5 mm defocus distance from the filter surface. The optimum transport efficiency for most of the elements can be obtained if the argon gas flow rate is kept at 0.8 L min –1 .