Determination of Ge, As and Se in nickel-based alloys by flow injection hydride generation dynamic reaction cell inductively coupled plasma mass spectrometry

Abstract

A dynamic reaction cell^™ inductively coupled plasma mass spectrometry (DRC-ICP-MS) method has been developed for the determination of Ge, As and Se in nickel-based alloys using flow injection hydride generation as the sample introduction system. The hydride generation technique alleviated the matrix-based interferences, such as ⁵⁸Ni¹⁶O⁺, ⁵⁹Co¹⁶O⁺ and ⁶²Ni¹⁶O⁺, on the determination of ⁷⁴Ge⁺, ⁷⁵As⁺ and ⁷⁸Se⁺. L-Cysteine is used as a masking agent to reduce the interferences arising from the transition metals. By using H₂ as the reactive cell gas in the DRC, the interferences arising due to the formation of ³⁵Cl³⁷Cl⁺, ³⁷Cl³⁷Cl⁺, ⁴⁰Ar³⁵Cl⁺ and ³⁸Ar⁴⁰Ar⁺ on the determination of ⁷²Ge⁺, ⁷⁴Ge⁺, ⁷⁵As⁺ and ⁷⁸Se⁺ have also been alleviated. The effects of the operating conditions of the hydride generation and DRC system have been studied to select the best signal-to-background ratio (S/B). Validation of the method is carried out by determining Ge, As and Se in standard reference materials of nickel-based alloys (NIST SRM 897–899). The concentrations of Ge, As and Se have been determined by standard addition and/or isotope dilution methods. The Se experimental results agreed satisfactorily with the certified values, and that of Ge and As with reference values obtained by pneumatic nebulization using high resolution ICP-MS. The detection limits for Ge, As and Se were in the range 0.001, 0.001 and 0.02 ng ml⁻¹, respectively, which corresponds to 1–20 ng g⁻¹ in the original alloy samples. The precision between sample replicates was better than 6% for all the determinations.