Inductively coupled plasma isotope detectors

Multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS) combines sector-field ICPMS with a multiple collector detector system and has recently emerged as an alternative to TIMS for precise U-Th isotope measurement. The full potential of MC-ICPMS has yet to be realized. Yet despite this, its performance in high precision isotope measurement already challenges and, in some cases, surpasses that ever achieved by TIMS (e.g., Lee and Halliday 1995 Blichert-Toft and Albarede 1997). 

The gas chromatograph may be interfaced with atomic spectroscopic instruments for specific element detection. This powerful combination is useful for speci-ation of different forms of toxic elements in the environment. For example, a helium microwave induced plasma atomic emission detector (AED) has been used to detect volatile methyl and ethyl derivatives of mercury in fish, separated by GC. Also, gas chromatographs are interfaced to inductively coupled plasma-mass spectrometers (ICP-MS) in which atomic isotopic species from the plasma are introduced into a mass spectrometer (see Section 20.10 for a description of mass spectrometry), for very sensitive simultaneous detection of species of several elements. 

TIMS, depending on the application [3]. These developments with magnetic sector instruments include multiple Faraday cup detectors (multicollectors) and multiple ion counters. The Faraday cup multicollectors have enabled the determination of isotope ratios with accuracy and precision rivaling TIMS [4], Due to lower sensitivity and differences in instrument design, quadrupole instruments (quadrupole inductively coupled plasma mass spectrometry [Q-ICP-MS]) have not demonstrated the same accuracy and precision as magnetic sector instruments, especially at low concentrations [5], Nevertheless, improvements in the sensitivity of quadrupole instrumentation have also increased their utility for many isotope ratio applications [6]. 

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