A FEASIBILITY STUDY OF THE USE OF ELECTROSTATIC DEPOSITION AND LASER-INDUCED FLUORESCENCE IN A GRAPHITE-FURNACE FOR SIZE-SEGREGATED ANALYSIS OF LEAD AND GOLD IN ULTRAFINE 0.02-0.2 MU-M PARTICLES

The analytical feasibility has been studied of determining lead in siz e-segregated ultrafine aerosols by laser-induced fluorescence (LIF) af ter the transport and deposition, under the influence of an electric f ield, of the isomobility aerosol in a graphite furnace. After calibrat ion with isomobility aerosols, the direct, size-segregated analysis of the lead content in a test aerosol in the 0.018-0.104 mu m diameter r ange was performed. Further, a brief study is presented of the depende nce of the particle collection efficiency on the particle diameter. To tal (polydisperse) lead concentrations in atmospheric ultrafine aeroso ls at the Ispra site were measured to be between 2.38 and 35.8 ng m(-3 ). The mass fraction, f(m), of lead in the unknown atmospheric particu late was calculated to be, on average, 4.81 x 10(-3). Results are also reported of initial studies of the analysis of gold in size-segregate d aerosols and of problems associated with monodisperse calibration. F inally, with an achievable limit of detection, defined as the mass yie lding a signal-to-noise ratio of 3, of 5 fe for lead and 3 fg for gold , estimates of the times required for the size-segregated analysis of their background levels in the above size range and in various atmosph eric aerosols are presented. These range from several minutes for the case of lead in an urban aerosol to many days for gold in average back ground aerosols. (C) 1997 Elsevier Science B.V.