UV LASER-ABLATION OPTICAL-EMISSION SPECTROMETRY ON ALUMINUM-ALLOYS INAIR AT ATMOSPHERIC-PRESSURE

An experimental arrangement for elemental analysis of solid samples in air at atmospheric pressure is presented. The arrangement couples opt ical emission spectroscopy with XeCl ultraviolet laser ablation. The e xperimental conditions to bring about optimum reproducibility of the a nalytical measurement are given. It is shown that the plasma emission signal is strongly dependent on the number of shots delivered at a giv en place. Hence, a good control of the ablation process requires a kno wledge of the exact number of shots delivered before and during signal s acquisition. Time resolved measurements where performed with a time delay in the range of 1-4 mu s in order to eliminate background emissi on and to avoid data recording during plasma collapse. Analytical perf ormances have been evaluated for detection of magnesium in aluminum al loys using the internal standard technique. Reproducibility was invest igated for several aluminum matrices, by comparing measurements perfor med over several days, and was found to be 2%. A single straight calib ration curve was obtained for four aluminum alloys, thus indicating th e absence of second order matrix effects.