Elemental analysis of airborne particulate matter using an electrical low-pressure impactor and laser ablation/inductively coupled plasma mass spectrometry

In this study, we investigated the elemental contents of airborne particulate matter, having dimensions in the nanometer (<0.1 mu m), submicrometer (0.1-1.0 mu m), and micrometer (>1.0 mu m) size ranges, collected using an electrical low-pressure impactor (ELPI). We used laser ablation/inductively coupled plasma mass spectrometry (LA-ICP-MS) to analyze the airborne particles trapped on filter media and to determine their elemental compositions. To simulate the ELPI collection of samples, we prepared laboratory-made standard filter samples by placing drops of liquid standard solutions onto the filter. The absolute limits of detection ranged from 2 x 10(-2) ng for Cd to 1.06 ng for Si. The mean relative standard deviation for five replicates using the standard filter ranged from 3.5 to 17.8%. To determine the accuracy of this protocol, we analyzed the airborne particles using a standard addition method. Comparison with the data obtained using a dichotomous sampler/ICP-MS method revealed that our proposed ELPI/LA-ICP-MS method allowed the elemental and physical characteristics of ultra-fine particles in the atmosphere to be monitored with suitable accuracy to satisfy the needs of environmental, safety, and health applications.