Determination of lanthanides in magnesium alloys by ion chromatography

A certain amount of lanthanide elements can be added to the magnesium metal alloys in order to improve their mechanical properties and corrosion behaviour. The light fraction La, Ce, Pr and Nd is normally added to the metal during the alloy production process. The determination of these elements in the magnesium alloy is usually carried out by different atomic spectroscopic techniques with the exception of cerium which is difficult to determine by atomic absorption spectroscopy (AAS) due to matrix interference. These techniques include X-ray fluorescence (XRF), optical emission spectroscopy (OES), inductive coupled plasma-mass spectroscopy (ICP-MS) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and AAS. This paper presents an analytical procedure for the determination of these elements in the magnesium alloy by ion chromatography. The determination of La, Ce, Pr, and Nd by cation exchange chromatography, ion interaction chromatography and anion exchange chromatography is also discussed. The accuracy and reproducibility of the cation exchange chromatographic method are investigated through standardized magnesium alloy materials. A comparison of analytical data was set up to study the suitability of this method against standard methods of analysis like ICP-AES and AAS spectroscopic techniques. It was apparent that data obtained from this work closely matches with data obtained from the two other methods of analysis. This work indicates that the determination of lanthanides in magnesium alloys by ion chromatography is fast, reliable and accurate.