Direct solid atomic emission spectrometric analysis of metal samples by anargon microwave plasma torch coupled to spark ablation

Spark ablation has been combined to microwave plasma torch atomic emission spectrometry for the direct analysis of compact metallic samples. The mater ial is ablated by a medium voltage spark (450 V, 370 Hz) in a point-to-plan e configuration and swept into a 100-W, 2.45-GHz argon microwave discharge. The microwave plasma is observed end-on and the radiation analysed with a polychromator. The detection limits for Fe, Ni, Pb and Sn in brass, Cr, Cu, Ni, Mn, Mo, Si and V in steel and Cu, Fe, Mg, Mn, Si and Zn in aluminium w ith the microwave plasma torch in the case of measurements with a polychrom ator are in the mu g/g range and by a factor of up to 20 higher than those obtained with spark ablation coupled to inductively coupled plasma atomic e mission spectrometry using a high resolution sequential spectrometer. The s tability of the emission signal depends on the element studied and relative standard deviations usually are between 0.5 and 3.5%. In the case of low-a lloy steels, the linearity and the precision of the calibration could be im proved by internal standardisation. Several elements (Cr, Cu, Ni, Si and V) could be determined in a steel sample (BAS SS 410/1) with high accuracy an d precision. (C) 1999 Elsevier Science B.V. All rights reserved.