Automated determination of tin and nickel in brass by on-line anodic electrodissolution and electrothermal atomic absorption spectrometry

The application of an on-line metallic alloy dissolution system using anodi c electrodissolution in a flow injection system for the determination of ti n and nickel in copper alloys is described. After the electrolyzed material was collected in the autosampler cup, determination was carried out using electrothermal atomic absorption spectrometry (ETAAS). Using specific softw are developed in Turbo Pascal 7.0, it is possible to control electrolysis t ime, intensity of the applied current, and triggering of the three-way sole noid valves that push the fluids. Through manipulation of these variables, it is possible to adjust the analytical signal to within the working range of the spectrometer. Calibration of the spectrometer was accomplished by pr ocessing reference material. For tin, relative standard deviations for a se ries of measurements (n = 5) performed on the same point and on different p oints of the sample was smaller than 2 and 4%, respectively; for nickel, 2 and 5%, respectively. The results for tin and nickel were in good agreement with those obtained through application of the classical methodology, as w ell as with data obtained by optical emission spectrometry. The detection l imit for tin was 0.001% (w/w), whereas for nickel it was 0.003% (w/w). The analytical throughput is 30 samples h(-1). (C) 1998 Elsevier Science B.V. A ll rights reserved.