ANALYTICAL CHARACTERISTICS IN ELECTROTHERMAL ATOMIZATION STUDIES OF CADMIUM, COPPER, GERMANIUM, MOLYBDENUM, LEAD AND VANADIUM FROM PYROLYTIC AND TUNGSTEN COATED LVOV PLATFORMS BY ATOMIC-ABSORPTION SPECTROMETRY

A physical vapour deposition-sputter ion plating method was used to coat new and exhausted pyrolytic graphite platforms of different designs. Tungsten carbide was sputtered onto the surfaces of the platforms and the analytical performance of Cu, Cd, Pb, Ge, V and Mo were tested on the tungsten-coated surfaces and compared with that obtained with standard pyrolytic graphite platforms. Exhausted platforms can be recuperated by the proposed procedure with sensitivities comparable to those obtained from the new pyrolytic platforms, with the exception of V and Mo. An increment in the pyrolysis temperature for the volatile elements Cd and Pb and the improvement in sensitivity for Ge are the major advantages of the tungsten-coated surfaces. The coating system has the advantage that several platforms can be coated simultaneously.