Determination of rare earth and concomitant elements in magnesium alloys by inductively coupled plasma optical emission spectrometry

摘要

An Inductively Coupled Plasma Optical Emission Spectrometry method for simultaneous determination of Al, Ca, Cu, Fe, In, Mn, Ni, Si, Sr, Y, Zn, Zr and rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in magnesium alloys, including the new rare earth elements-alloyed magnesium, has been developed. Robust conditions have been established as nebulizer argon flow rate of 0.5 mL min(-1) and RF incident power of 1500 W, in which matrix effects were significantly reduced around 10%. Three acid digestion procedures were performed at 110 degrees C in closed PFA vessels heated in an oven, in closed TFM vessels heated in a microwave furnace, and in open polypropylene tubes with reflux caps heated in a graphite block. The three digestion procedures are suitable to put into solution the magnesium alloys samples. From the most sensitive lines, one analytical line with lack or low spectral interferences has been selected for each element. Mg, Rh and Sc have been studied as internal standards. Among them, Rh was selected as the best one by using Rh I 343.488 nm and Rh II 249.078 nm lines as a function of the analytical lines. The trueness and precision have been established by using the Certified Reference Material BCS 316, as well as by means of recovery studies. Quantification limits were between 0.1 and 9 mg kg(-1) for Lu and Pr, respectively, in a 2 g L-1 magnesium matrix solution. The method developed has been applied to the commercial alloys AM60, AZ80, ZOO, AJ62, WE54 and AE44. (c) 2016 Elsevier B.V. All rights reserved.