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

摘要

The analytical feasibility has been studied of determining lead in size-segregated ultrafine aerosols by laser-induced fluorescence (LIF) after the transport and deposition, under the influence of an electric field, of the isomobility aerosol in a graphite furnace. After calibration 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 range was performed. Further, a brief study is presented of the dependence of the particle collection efficiency on the particle diameter. Total (polydisperse) lead concentrations in atmospheric ultrafine aerosols 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 particulate 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-segregated aerosols and of problems associated with monodisperse calibration. Finally, with an achievable limit of detection, defined as the mass yielding 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 atmospheric aerosols are presented. These range from several minutes for the case of lead in an urban aerosol to many days for gold in average background aerosols. (C) 1997 Elsevier Science B.V. [References: 65]