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

Abstract

The determination of tin in nickel-based alloys by laser-excited atomic fluorescence in a graphite furnace was investigated. The concentrations of tin in four nickel-based alloys from Pratt & Whitney Aircraft were determined. The nickel in the alloys was found to behave as a permanent chemical modifier that remained in the graphite tube during analyses. The use of a mixture of hydrofluoric, hydrochloric and nitric acids proved to be the most efficient dissolution method. In order to confirm the accuracy of the results, Zeeman-effect background corrected ETAAS and ICP-MS methods were also used. The results from these different methods were compared by use of the Student’s t -test. The laser-excited atomic fluorescence method was found to be as accurate as the other techniques. The precisions of the techniques varied from 4 to 12% RSD. For the dissolution of 100 mg of nickel alloy in 100 ml of aqueous solution, the effective atomic fluorescence detection limit in the original nickel alloy samples was 1.5 ng g ^-1 . The atomic fluorescence method was simple to develop and did not need a sophisticated background correction technique to perform the analyses.