DETERMINATION OF TIN IN NICKEL-BASED ALLOYS BY ELECTROTHERMAL LASER-EXCITED ATOMIC FLUORESCENCE WITH CONFIRMATION OF ACCURACY BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY AND ATOMIC-ABSORPTION SPECTROMETRY

The determination of tin in nickel-based alloys by laser-excited atomi c fluorescence in a graphite furnace was investigated, The concentrati ons of tin in four nickel-based alloys from Pratt & Whitney Aircraft w ere determined, The nickel in the alloys was found to behave as a perm anent chemical modifier that remained in the graphite tube during anal yses. The use of a mixture of hydrofluoric, hydrochloric and nitric ac ids proved to be the most efficient dissolution method. In order to co nfirm the accuracy of the results, Zeeman-effect background corrected ETAAS and ICP-MS methods were also used, The results from these differ ent methods were compared by use of the Student's t-test, The laser-ex cited atomic fluorescence method was found to be as accurate as the ot her techniques, The precisions of the techniques varied from 4 to 12% RSD, For the dissolution of 100 mg of nickel alloy in 100 mi of aqueou s solution, the effective atomic fluorescence detection limit in the o riginal nickel alloy samples was 1.5 ng g(-1). The atomic fluorescence method was simple to develop and did not need a sophisticated backgro und correction technique to perform the analyses.