Determination of 90Sr and 226Ra for the first time in an IAEA proficiency test (ICP-QQQ-MS) / 20.12.2023
This is the first time that an ICP-QQQ-MS (Agilent 8900 triple quadrupole mass spectrometer) method met the accuracy and precision criteria for a proficiency test in the quantification of 90Sr and 226Ra at an environmental level.
Typically, radiometric techniques are mostly employed for the examination of the artificial 90Sr and the natural 226Ra, where the emission of beta and alpha particles resulting from the radioactive decay of 90Sr and 226Ra is measured using various types of detectors, including gas ionization detectors, solid or liquid scintillators, and so on. Recent advancements in sample introduction, detector technology, and interference reduction techniques have led to numerous successful determinations of 90Sr and 226Ra utilizing mass spectrometry instruments. Inductively coupled plasma mass spectrometry (ICP-MS) devices equipped with collision/reaction cells or triple quadrupole systems have been predominantly utilized for this purpose.
The primary benefits of the mass spectrometry technique compared to radiometric methods include reduced analysis time, increased sample throughput, and decreased sample size.
Detecting low levels of 90Sr in environmental samples using a mass spectrometry instrument is difficult. The primary crucial aspect is the occurrence of isobaric interference of 90Zr due to substantial quantities of the Zr element in environmental samples. A further crucial factor is the peak tailing on the higher mass side from 88Sr. There is no isobaric interference for 226Ra, but the analysis may be affected by polyatomic interference, such as from Sr and Ba.
To achieve a higher degree of quality assurance, it is important to participate in proficiency tests administered by an internationally acknowledged reference laboratory. To meet this requirement, our laboratory took part in the IAEA-TERC-2023-01/02 World Wide Open & ALMERA proficiency test exercise organized by the International Atomic Energy Agency (IAEA). Agilent 8900 triple quadrupole ICP-MS was used for the first time in a proficiency test for 90Sr and 226Ra analysis, a field typically dominated by radiometric methods.
The outcomes of this work indicate that our scientific efforts to widen the analytical capabilities of inorganic mass spectrometry have been successful.
This is the first time that an ICP-QQQ-MS (Agilent 8900 triple quadrupole mass spectrometer) method met the accuracy and precision criteria for a proficiency test in quantifying 90Sr and 226Ra at an environmental level.
This new method, developed by the researchers from Jožef Stefan Institute (Slovenia) and Ruđer Bošković Institute (Croatia) is very competitive with traditional radiometric methods in terms of accuracy, precision, and detection limit. The implementation of accreditation and regular use of this method is anticipated in the near future, resulting in a substantial reduction in the time required for 90Sr and 226Ra measurements in environmental and biological samples.
Dr. Norbert Kavasi
Reported results and evaluation parameters of 90Sr (tap water) in IAEA-TERC-2023-01/02 proficiency test
