Abstract

A recently introduced inductively coupled plasma-time-of-flight-mass spectrometer (ICP-ToF-MS) shows enhanced sensitivity compared to previous developments and superior isotope ratio precision compared to other ToF and commonly used single-collector ICP-MS instruments. Following this fact, an improvement for isotope dilution ICP-MS using the new instrumentation has been reported. This study aimed at investigating whether this improvement also meets the requirements of species-specific isotope dilution using GC/ICP-MS, where short transient signals are recorded. The results of the analysis of monomethylmercury (MMHg) of a sediment reference material show that isotope ratio precision of ICP-MS instruments equipped with quadrupole, sector-field, and time-of-flight mass analyzers is similar within a broad range of peak signal-to-noise ratio when analyzing one isotopic system. The procedural limit of quantification (LOQ) for MMHg, expressed as mass fraction of Hg being present as MMHg, w(Hg)MMHg, was similar as well for all investigated instruments and ranged between 0.003 and 0.016 μg/kg. Due to the simultaneous detection capability, the ICP-ToF-MS might, however, be more favorable when several isotopic systems are analyzed within one measurement. In a case study, the GC/ICP-ToF-MS coupling was applied for analysis of MMHg in sediments of Finow Canal, a historic German canal heavily polluted with mercury. Mass fractions between 0.180 and 41 μg/kg (w(Hg)MMHg) for MMHg, and 0.056 and 126 mg/kg (w(Hg)total) for total mercury were found in sediment samples taken from the canal upstream and downstream of a former chemical plant.Graphical abstract

Highlights

  • Species-specific isotope dilution (SSID) analysis is a primary method producing most reliable and precise results [1, 2]

  • Since ICP-ToF-MS instruments work with a quasisimultaneous detection of all m/z ratios, they were shown to be superior to instruments with sequential mass analyzers, such as quadrupole (Q) and single-collector magnetic sectorfield (SF) ICP-MS instruments, regarding isotope ratio precision [4, 5]

  • These comparisons have only been conducted with standard continuous liquid introduction analyses and are not readily transferable to the measurement of isotope ratios in transient signals, as it is the case for hyphenations of ICP-MS with separation techniques, such as GC, HPLC, IC, or CE

Read more

Summary

Introduction

Species-specific isotope dilution (SSID) analysis is a primary method producing most reliable and precise results [1, 2]. Since ICP-ToF-MS instruments work with a quasisimultaneous detection of all m/z ratios, they were shown to be superior to instruments with sequential mass analyzers, such as quadrupole (Q) and single-collector magnetic sectorfield (SF) ICP-MS instruments, regarding isotope ratio precision [4, 5]. These comparisons have only been conducted with standard continuous liquid introduction analyses and are not readily transferable to the measurement of isotope ratios in (short) transient signals, as it is the case for hyphenations of ICP-MS with separation techniques, such as GC, HPLC, IC, or CE. This is due to poorer statistics resulting from the short time available for the isotope ratio measurement and small analyte quantity [6]

Objectives
Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call