Determination of trace elements in superalloys by inductively coupled plasma mass spectrometry with micro-reaction pretreatment

Due to complex pretreatment processes and the consumption of large amounts of high-purity chemical reagents, traditional analytical methods for determining trace element concentrations in superalloys face severe challenges. In this paper, a micro-reaction pretreatment method was developed by using a micro-reaction sealed digestion vessel under micro-pressure. The mass of the samples and the volume of acid used to dissolve the superalloys were significantly reduced. Five dissolution systems and three universal dissolution devices were studied. The quantitative dilution process was optimized to minimize errors through meticulous weighing procedures using a high-precision balance, and the homogeneity of the samples was verified by using Ni-based superalloy standards and general samples. Sc, Rh, and Re were selected for internal standard correction, and the matrix effect was corrected by the matrix matching method. Moreover, the mass spectral interference caused by polyatomic ions was eliminated by He collision mode. The linear correlation coefficients of the calibration curves were above 0.9995, with linear coefficients ranging from 0.1 to 100 ng/mL. The detection limits for the method ranged from 0.0042 to 0.13 μg/g, and the quantification limits ranged from 0.014 to 0.41 μg/g. The results showed the precision and reliability of the newly established green micro-reaction pretreatment scheme for the determination of Ga, As, In, Sn, Sb, Tl, Pb, and Bi in nickel-based superalloys together with inductively coupled plasma mass spectrometry. The micro-reaction test results of the various groups were consistent with those of the traditional methods, and the relative standard deviation (RSD, n = 11) was less than 10 %. In addition to reducing acid consumption and increasing the test solution utilization rate by ten times, the micro-reaction method was much more accessible from cross-contamination and intensive manual work, so it has shown great potential for application in intelligent and automatic batch testing of trace elements in superalloys.