Analysis of doped luminescent lanthanide fluoride nanoparticles by low gas flow inductively coupled plasma optical emission spectrometry

Engelhard C, Vielhaber T, Scheffer A, Brocksieper M, Buscher W, Karst U

Abstract

Low-flow inductively coupled plasma optical emission spectrometry is applied for the analysis of water-soluble LaF3 nanocrystals doped with different lanthanide ions (Ce3+, Eu3+, Ho3+, Tb3+) for the first time. Colloidal solutions of citrate-stabilized nanoparticles (mean size 24 nm) were directly introduced into the plasma and no significant differences to digested particles were observed. The low-flow approach reduced the argon consumption of conventional instrumentation by 95% and provided limits of detection (LOD) for rare earth elements in the low microgram-per-liter range (Eu: 0.08 mu g L-1, Ho: 0.18 mu g L-1, La: 0.36 mu g L-1, Tb: 0.56 mu g L-1, Ce: 3.14 mu g L-1). Relative standard deviations (RSDs) in the range of 1-2.2% with pneumatic sample introduction were obtained. The analytical performance of the low-flow torch was assessed by direct comparison with a conventional torch. I. Recoveries in the range of 97-104% were observed for most elements.