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

Abstract

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.

Advances in Analytical Techniques and Applications in Exploration, Mining, Extraction, and Metallurgical Studies of Rare Earth Elements

“…The spectral interference problem can be minimized by (i) procedural blank subtraction, (ii) a temperature-controlled sample introduction system, (iii) mathematical interference correction, (iv) offline and online sample pre-treatment methods, (v) internal standardization, (vi) the standard addition method, (vii) the isotope dilution method, (viii) the use of mixed plasmas, (ix) matrixmatching calibration, (x) the use of cool plasma technology, (xi) the use of high-resolution ICP-MS, and (xii) the use of collision/reaction technology [111]. However, recent studies by several authors demonstrated that the use of tandem ICP-MS or ICP-MS/MS with a collision/reaction cell (operated with gases, like NH 3 , O 2 , and N 2 O) sandwiched by two quadrupole analyzers, and measuring all REE either on-mass mode or mass-shift mode, provided the best results with detection limits at sub-pg/mL levels (Table 5) for different REEs [111,112]. Some studies indicated that NH 3 as a cell gas was found to react with many of the polyatomic ions that interfere with the REEs and is useful in eliminating/minimizing interferences.…”

“…However, NH 3 also reacts with some of the REEs leading to reduced sensitivity. On the other hand, Zhu [112] found that N 2 O as a reaction gas gave more accurate values compared to the use of O 2 gas when REEs were determined by ICP-MS/MS when both N 2 O and O 2 were used as reaction gases for the removal of interferences during the determination of the whole set of REEs in river water reference material. Especially the use of N 2 O as the reaction gas helped to suppress Ba-related spectral interferences, and also yielded lower detection limits.…”

Sensitive and accurate determination of REEs using a high-efficiency miniaturized ultrasonic nebulization sampling system coupled with the inductively coupled plasma mass spectrometer

“…Although the Ar-ICP provides high ionization efficiency (close to 100%) for the sensitive measurements of all REEs, 43 polyatomic spectral interferences, such as oxide, can pose challenges in accurately quantifying REEs, for example, 139 La 16 O + , 150 Sm 16 O + , and 159 Tb 16 O + interfering with the measurement of 155 Gd + , 166 Er + and 175 Lu + , respectively. The CRC is a simpler and more effective method to solve these oxide interferences compared to other methods, such as mathematic correction, chemical separation, and high-resolution ICP-MS. [43][44][45] However, it should be noted that the use of a CRC in ICP-MS potentially reduces the sensitivity of the analyte. 46 By reducing the moisture introduced into the ICP, MUN can potentially reduce the formation of polyatomic ions without compromising sensitivity, which may offer an alternative approach to solve this issue.…”

Atomic spectrometry update – a review of advances in environmental analysis

“…IH 2 + background signal.Using both gases simultaneously resulted in a LOD of 0.73 mBq L −1 (0.11 ng L −1 ) thereby making it possible to determine129 I in rainwater without any chemical separation even in the presence of up to 100 mg L −1 127 I. The use of N 2 O as a reaction gas improved78 slightly the determination of REEs in river water by boosting the yields of153 Eu 16 O + and 172 Yb 16 O + in the reaction cell in mass shi mode. In addition, Ba-related spectral interferences on Eu were suppressed so there was no need for spectral interference corrections.…”