ICP-QQQ Applications in Geochemistry, Mineral Analysis, and Nuclear Science

Význam tématu
Rare Earth Elements (REEs) are key targets for radiolabeling in pharmaceutical and imaging applications, yet their chemical similarity complicates the production of high‐purity radioisotopes. Precise knowledge of trace REE impurities is essential to ensure radiolabeling efficiency, reduce by‐product formation, and guide robust separation protocols.

Cíle a přehled studie / článku
This work demonstrates how Agilent Triple Quadrupole ICP‐MS (ICP‐QQQ) in MS/MS mode with O₂ reaction gas can directly quantify ppt‐level REE impurities in bulk REE matrices, resolve isobaric and polyatomic interferences, and support both method development and irradiated‐target assessment without extensive chemical separation.

Použitá metodika a instrumentace
Calibration standards of trace REE analytes (1 ppt–100 ppb) were prepared in 10 ppm REE matrices. Bulk REE materials—including Gd₂O₃ powders and irradiated Gd targets—were dissolved in 2 vol% HNO₃. The Agilent 8800 ICP‐QQQ equipped with a quartz torch, Scott spray chamber, and concentric nebulizer operated in MS/MS mode (Q1=target m/z, Q2=product m/z) with O₂ cell gas (0.3 mL/min), octopole bias –5 V, and energy discrimination –7 V.

Hlavní výsledky a diskuse
• Detection limits (DLs) of 2–20 ppt and background equivalent concentrations (BECs) < 1 ppt were achieved for most trace REEs measured against 10 ppm neighboring REE matrices (e.g., Tb in Gd).
• MS/MS O₂ mass‐shift fully eliminated adjacent‐mass oxide/hydride interferences (e.g., 158Gd¹⁶O⁺ on 174Yb⁺), enabling accurate low‐level quantification. Single Quadrupole modes failed to resolve these overlaps.
• Analysis of natural Gd₂O₃ powder and an ICP‐standard revealed La and Ce impurities (1–13 ppm), later reduced below detection after radiochemical separation.
• An LN resin chromatographic protocol spiked with ppt‐level Tb in 5×10⁴× Gd demonstrated that MS/MS monitoring of eluted fractions can identify incomplete separation and confirm minimal matrix bias.

Přínosy a praktické využití metody
• Rapid batch‐to‐batch QA of REE starting materials for radioisotope production.
• Stable‐isotope analog measurements replace radioactive targets during method development, reducing cost and hazard.
• Post‐irradiation impurity profiling validates chemical separation efficiency and supports reuse of lanthanide targets.

Budoucí trendy a možnosti využití
• Application to enriched or recycled lanthanide sources to improve sustainability of radioisotope production.
• Adoption of UHMI plasma conditions on next‐generation ICP‐QQQ instruments for high matrix tolerance up to 25 % TDS.
• Extension to actinide and mixed‐lanthanoid workflows to enhance separation protocols and minimize radiocontamination.

Závěr
Agilent ICP‐QQQ in MS/MS mode with O₂ reaction cell chemistry delivers a robust, interference‐free platform for ppt‐level trace REE impurity analysis in bulk matrices. This capability streamlines QA, accelerates separation development, and ensures high‐purity radio-lanthanide production without extensive pretreatment.

Reference
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3. Sugiyama N. et al. Appl. Radiat. Isot., 2017, 126, 31–34.
4. Sugiyama N. Agilent Application Note, 2012, 5991-0892EN.