Laser enhanced ionization of mercury atoms in an inert atmosphere with avalanche amplification of the signal
A new method for laser enhanced ionization detection of mercury atoms in an inert gas atmosphere has been developed. The method, which is based on the avalanche amplification of the signal resulting from the ionization from a selected Rydberg level reached by a three-step laser excitation of mercury vapour in a simple quartz cell, can be applied to determination of this element in various matrices by the use of conventional cold-atomization techniques. The overall (collisional + photoionization) ionization efficiency is investigated at different temperatures and the avalanche amplification effect is reported for Ar and P-10 gases at atmospheric pressure. It is shown that the amplified signal is related to the number of charges produced in the laser irradiated volume. Under amplifier-noise limited conditions, a detection limit of about 6 Hg atoms per laser pulse in the interaction region is calculated.
Bibliographic Reference: Article: Analytical Chemistry
Record Number: 199710681 / Last updated on: 1997-06-10
Original language: en
Available languages: en