PERFORMANCE AND CHARACTERISTICS OF 2 TOTAL-REFLECTION X-RAY-FLUORESCENCE AND A PARTICLE-INDUCED X-RAY-EMISSION SETUP FOR AEROSOL ANALYSIS

Two X-ray emission techniques, total-reflection X-ray fluorescence (TX RF) and proton induced X-ray emission (PIXE), were applied to atmosphe ric trace element determinations and compared with respect to detectio n properties, speed of analysis, precision and sampling strategy. The advantage of the commercial TXRF system over all the other techniques evaluated was clearly demonstrated. The lowest detection limits were f ound to be at a level of 0.01 ng m(-3). The use of an economical TXRF module exhibited reasonably satisfactory results in this atmospheric r esearch study; the detection limits were about one order of magnitude less favourable than those of the commercial unit. For TXRF, aerosols were collected directly on quartz glass or Plexiglas(R) carriers in a single-orifice impactor during 3-5 h; the measuring time was some minu tes. For PIXE, aerosols were deposited on Nuclepore(R) filters during 48 h, PIXE was performed under less than optimal conditions using 1.4 MeV protons, and therefore the PIXE detection limits were also recalcu lated for an optimised setup using 2.5 MeV protons. (C) 1997 Elsevier Science B.V.