A commercial hollow cathode lamp is used as an atom reservoir for the atomic fluorescence of lead excited by a copper laser pumped dye laser. The glow discharge source is nearly an ideal atom cell for such measurements, having very low background emission and excellent atomization characteristics. A detection limit of 1.8 ag of lead within the laser beam is easily obtained.
B. W. Smith, J. B. Womack, N. Omenetto, and J. D. Winefordner, "Approaching Single Atom Detection with Atomic Fluorescence in a Glow Discharge Atom Reservoir," Appl. Spectrosc. 43, 873-876 (1989)