GLOW-DISCHARGE MASS-SPECTROMETRIC ANALYSIS OF ATMOSPHERIC PARTICULATEMATTER

A direct current (dc) glow discharge mass spectrometer has been used t o analyze atmospheric particulate matter, The sample preparation used is simple and time-saving, The air is sucked by a pump through a singl e-orifice impactor stage, in which the aerosols are impacted on a meta l support, forming a central spot. This metal plate is directly used a s a cathode in a de glow discharge mass spectrometer. Evaluation of th e sample loading and of the discharge parameters allowed us to optimiz e the signal intensity and to minimize its decrease, the latter being a consequence of its consumption by continuous sputtering in the disch arge, The available aerosol analysis time could be prolonged to more t han 3 h, a time span necessary to perform a multielement analysis usin g a magnetic sector instrument and long integration times. A NIST refe rence aerosol was measured to evaluate the quantitative analysis poten tial, The internal reproducibility was better than 10% RSD, and the li mits of detection were estimated to be in the low ppm or sub ppm regio n, Even without the use of any standards or correction factors, glow d ischarge mass spectrometry could offer good semiquantitative results, based only on the use of an internal standard.