Determination of rare earth elements in environmental samples with high concentrations of barium by quadrupole inductively coupled plasma mass spectrometry

Determination of Rare Earth Elements by Inductively Coupled Plasma–Tandem Quadrupole Mass Spectrometry With Nitrous Oxide as the Reaction Gas

Nitrous oxide (N2O) was investigated as the reaction gas for the determination of rare earth elements (REEs) by inductively coupled plasma–tandem quadrupole mass spectrometry (ICP-QMS/QMS). The use of N2O as the reaction gas apparently improved the yields of mM16O+ for Eu and Yb in the reaction cell. As a result, the sensitivities for measurement of Eu and Yb were apparently improved in comparison to those obtained with O2 as the reaction gas. A high sensitivity measurement of the whole set of REEs was achieved, providing a typical sensitivity of 300,000 CPS mL/ng for REEs measured with an isotope having isotopic abundance close to 100%. The use of N2O as the reaction gas helped suppress Ba-related spectral interferences with the measurement of Eu, permitting the measurement of Eu in a natural sample without mathematic correction of spectral interferences. The detection limits (unit, pg/mL) for 14 REEs (except for Pm) from La to Lu were 0.028, 0.018, 0.006, 0.026, 0.006, 0.010, 0.017, 0.006, 0.016, 0.010, 0.016, 0.004, 0.023, and 0.012, respectively. The validity of the present method was confirmed by determining REEs in river water-certified reference materials, namely, SLRS-3 and SLRS-4.

Possible sources of rare earth elements near different classes of road in Poland and their phytoextraction to herbaceous plant species

The growing use of rare earth elements (REE) in industry determines their increased transport to the environment. The higher concentration of this group of elements in soils near roads may also suggest that traffic plays a significant role in their distribution. The aim of this study was to examine the content of REEs in selected consumables (car parts, asphalt) and environmental samples (plants, soils) in order to estimate the extent to which these elements derive from traffic and also to analyze their phytoextraction from soil by selected herbaceous plants species. Research materials were car parts (5 brake pads, 10 new tires - summer and winter), 20 samples of asphalt and road dust settled on its surface; soil, and 7 plants species growing at a distance of 1 m from the edge of the 5 roads located in the Wielkopolska Voivodeship, Poland. The content of REEs in the collected samples was determined using inductively coupled plasma optical emission spectrometer. The content of REEs in asphalt and brake pads was similar and significantly higher than in tires. According to the mass of particular stripped materials, the main source of these elements was asphalt. The amount of REEs released from tires to the environment was found to be much lower than REEs released from asphalt but generally higher than from brake pads. The content of REEs in the soil was found to increase in accordance with traffic intensity, but chemical composition of soil was the main determinant of the uptake these elements, mainly via the root systems of plants. The obtained results suggest that densely vegetated roadsides and verges could be an effective strategy for decontamination of soils polluted with REEs, although the most effective remedy would involve significant changes in the production technologies of automotive parts and asphalt that would limit the emission of elements to environment.