Stable chlorine isotope ratio analysis of subnanomolar level methyl chloride by continuous-flow isotope ratio mass spectrometry

抄録

An analytical system using continuous-flow isotope ratio mass spectrometry (CF-IRMS) was developed to determine the stable chlorine isotope ratios (δ³⁷Cl) for CH₃Cl. By using appropriate devices for sample processing prior to introduction into the spectrometer, the newly developed system successfully reduces sample requirements (>0.6 nmol-CH₃Cl) to less than one hundredth of that required by the previous CF-IRMS systems while maintaining comparable precision in the δ³⁷Cl determination (±0.1‰, 1σ). This system is also able to determine carbon isotope ratio for CH₃Cl with comparable precision (±0.3‰, 1σ, >0.3 nmol-CH₃Cl) to the previous study. δ³⁷Cl_SMOC and δ¹³C_VPDB values of CH₃Cl in commercial tank were determined to be -6.8 ± 0.1‰ and -46.9 ± 0.3‰, respectively.