Abstract
A miniature glow discharge (GD) is evaluated as an atom reservoir for laser-excited atomic fluorescence spectrometric measurements of Eu, Y, and Tm. Nanoliter-sized aqueous samples are deposited and dried on the Ni cathode and atomized upon ignition of the GD. The atom population is probed by a copper vapor laser pumped dye laser, and direct-line fluorescence is detected. The optimum chamber pressures and operating currents are 1 Torr and 10 mA for Eu, 2 Torr and 10 mA for Y, and 3 Torr and 40 mA for Tm. The fluorescence temporal profiles are found to consist of short (∼20-ms duration) transient spikes, followed by long tails which last more than 60 s as a result of sample redeposition on the cathode surface. The limits of detection (3a) are 2 fg, 1.2 pg, and 0.08 fg for Eu, Y, and Tm, respectively, with the use of signal area integration over a 6-s duration. Theoretically simulated signals for a particular sample mass, considering the geometry of the GD atomizer, were found to fall within one order of magnitude of those obtained by experiment.
Get full access to this article
View all access options for this article.