Solid Sampling Approach in Inductively Coupled Plasma Atomic Emission Spectrometry for the Determination of Four Lanthanides With High Sensitivity

Abstract

A solid sampling technique was developed for the ICP-AES determination of ultra-trace amounts of lanthanides chemically separated from U/Pu fuel materials. An essentially dc arc approach of using a buffer–carrier mixture of graphite–AgCl (4+1) was adopted to facilitate volatilization of the lanthanides. A 20 µl volume of lanthanide solution is loaded on 20 mg of carrier–buffer mixture placed in the crater of a Scribner–Mullin type of electrode system, evaporated under an IR lamp and introduced into the running argon plasma using a modified plasma torch assembly. The near total introduction of sample vapour into the plasma allows the determination of Dy and Eu at the 0.4 ng level and Gd and Sm can be determined at the 1 and 2 ng levels, respectively, with a precision of 10% RSD. The method is free from interferences due to the presence of concomitant lanthanides and common metals and has a significantly high tolerance to the presence of refractory U–Pu matrices.