TY - JOUR
T1 - Compound-specific chlorine isotope analysis
T2 - A comparison of gas chromatography/isotope ratio mass spectrometry and gas chromatography/quadrupole mass spectrometry methods in an interlaboratory study
AU - Bernstein, Anat
AU - Shouakar-Stash, Orfan
AU - Ebert, Karin
AU - Laskov, Christine
AU - Hunkeler, Daniel
AU - Jeannottat, Simon
AU - Sakaguchi-Söder, Kaori
AU - Laaks, Jens
AU - Jochmann, Maik A.
AU - Cretnik, Stefan
AU - Jager, Johannes
AU - Haderlein, Stefan B.
AU - Schmidt, Torsten C.
AU - Aravena, Ramon
AU - Elsner, Martin
PY - 2011/10/15
Y1 - 2011/10/15
N2 - Chlorine isotope analysis of chlorinated hydrocarbons like trichloroethylene (TCE) is of emerging demand because these species are important environmental pollutants. Continuous flow analysis of noncombusted TCE molecules, either by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) or by GC/quadrupole mass spectrometry (GC/qMS), was recently brought forward as innovative analytical solution. Despite early implementations, a benchmark for routine applications has been missing. This study systematically compared the performance of GC/qMS versus GC/IRMS in six laboratories involving eight different instruments (GC/IRMS, Isoprime and Thermo MAT-253; GC/qMS, Agilent 5973N, two Agilent 5975C, two Thermo DSQII, and one Thermo DSQI). Calibrations of 37Cl/ 35Cl instrument data against the international SMOC scale (Standard Mean Ocean Chloride) deviated between instruments and over time. Therefore, at least two calibration standards are required to obtain true differences between samples. Amount dependency of δ 37Cl was pronounced for some instruments, but could be eliminated by corrections, or by adjusting amplitudes of standards and samples. Precision decreased in the order GC/IRMS (1σ ≈ 0.1°), to GC/qMS (1σ ≈ 0.2-0.5° for Agilent GC/qMS and 1σ ≈ 0.2-0.9° for Thermo GC/qMS). Nonetheless, δ 37Cl values between laboratories showed good agreement when the same external standards were used. These results lend confidence to the methods and may serve as a benchmark for future applications.
AB - Chlorine isotope analysis of chlorinated hydrocarbons like trichloroethylene (TCE) is of emerging demand because these species are important environmental pollutants. Continuous flow analysis of noncombusted TCE molecules, either by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) or by GC/quadrupole mass spectrometry (GC/qMS), was recently brought forward as innovative analytical solution. Despite early implementations, a benchmark for routine applications has been missing. This study systematically compared the performance of GC/qMS versus GC/IRMS in six laboratories involving eight different instruments (GC/IRMS, Isoprime and Thermo MAT-253; GC/qMS, Agilent 5973N, two Agilent 5975C, two Thermo DSQII, and one Thermo DSQI). Calibrations of 37Cl/ 35Cl instrument data against the international SMOC scale (Standard Mean Ocean Chloride) deviated between instruments and over time. Therefore, at least two calibration standards are required to obtain true differences between samples. Amount dependency of δ 37Cl was pronounced for some instruments, but could be eliminated by corrections, or by adjusting amplitudes of standards and samples. Precision decreased in the order GC/IRMS (1σ ≈ 0.1°), to GC/qMS (1σ ≈ 0.2-0.5° for Agilent GC/qMS and 1σ ≈ 0.2-0.9° for Thermo GC/qMS). Nonetheless, δ 37Cl values between laboratories showed good agreement when the same external standards were used. These results lend confidence to the methods and may serve as a benchmark for future applications.
UR - http://www.scopus.com/inward/record.url?scp=80054712213&partnerID=8YFLogxK
U2 - https://doi.org/10.1021/ac200516c
DO - https://doi.org/10.1021/ac200516c
M3 - Article
C2 - 21851081
SN - 0003-2700
VL - 83
SP - 7624
EP - 7634
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 20
ER -