Determination of trace cadmium in nickel-based superalloy by glow discharge mass spectrometry
When glow-discharge mass spectrometry(GDMS)is used to determine trace cadmium in nickel-based superalloy,it is interfered by 114Sn+and MoO+polyatomic ions.After pre-correction with standard relative sensitivity factor(RSFstd),the mass spectral interferences of multi-atomic ions including 114Sn+and MoO+were corrected by interference correction equation.Thus,a method for determination of trace cad-mium in nickel-based superalloy was realized by GDMS at high-resolution mode with 114Cd as analytical iso-tope.The instrument parameters were optimized as follows:the discharge current was 48 mA;the flow rate of discharge gas was 450 mL/min;the pre-sputtering time was 20 min.The certified reference materi-als of nickel-based wrought superalloy with Cd certified value less than 0.1 μg/g and Mo mass fraction of 3％were used as blank samples and determined for 11 times consecutively.The limit of election and limit of quantifiation,which were calculated according to three-fold and ten-fold of standard deviation of blank sample,were 0.081 μg/g and 0.27 μg/g,respectively.The content of cadmium in certified reference ma-terial or reference material of nickel-based superalloy were determined according to the proposed method,and the results were in good agreement with the certified value/standard value.The relative standard devi-ations(RSD,n=6)were less than 12％.The contents of cadmium in 3 nickel-based superalloy samples were determined according to the proposed method as well as inductively coupled plasma tandem mass spectrometry(ICP-MS/MS),respectively.The results showed that the results of the above two methods were basically consistent.
glow discharge mass spectrometry(GDMS)nickel-based superalloycadmiummolybdenum
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