LASER VAPORIZATION OF SOLID SAMPLES INTO A HOLLOW-CATHODE DISCHARGE FOR ATOMIC EMISSION-SPECTROMETRY

A hollow cathode discharge system has been developed for atomic emission spectrometry of solid samples. In this system, a solid sample is vaporized by a Q-switched Nd:YAG laser, and the vaporized material is introduced into a hollow cathode discharge by means of an argon gas flow. A photodiode array detector is used to acquire the spectral data and the spatial intensity profiles of atomic lines in the cathode bore. Experimental parameters which have been optimized include the pressure and flow rate of argon gas, the forms of the electrodes, and the discharge current. The laser is operated in either single pulse mode or multiple pulse mode, 20 pulses at 10 Hz repetition rate. The latter mode offers improved precision and detection limits, and quasi-continuous emission signals. Analytical curves obtained for standard samples of aluminum alloys are linear over 3 orders of magnitude with a relative standard deviation of 1.6-4.6%, and the estimated detection limits for the various elements range from 3 μg g-1 for Mg to 16 μg g-1 for Ni. © 1990.