Kalin R M, Hamilton J T, Harper D B, Miller L G, Lamb C, Kennedy J T, Downey A, McCauley S, Goldstein A H
Environmental Engineering Research Centre, School of Civil Engineering, The Queen's University of Belfast, Belfast BT9 5AG, UK.
Rapid Commun Mass Spectrom. 2001;15(5):357-63. doi: 10.1002/rcm.219.
Gas chromatography/mass spectrometry/isotope ratio mass spectrometry (GC/MS/IRMS) methods for delta(13)C measurement of the halomethanes CH(3)Cl, CH(3)Br, CH(3)I and methanethiol (CH(3)SH) during studies of their biological production, biological degradation, and abiotic reactions are presented. Optimisation of gas chromatographic parameters allowed the identification and quantification of CO(2), O(2), CH(3)Cl, CH(3)Br, CH(3)I and CH(3)SH from a single sample, and also the concurrent measurement of delta(13)C for each of the halomethanes and methanethiol. Precision of delta(13)C measurements for halomethane standards decreased (+/-0.3, +/-0.5 and +/-1.3 per thousand) with increasing mass (CH(3)Cl, CH(3)Br, CH(3)I, respectively). Given that carbon isotope effects during biological production, biological degradation and some chemical (abiotic) reactions can be as much as 100 per thousand, stable isotope analysis offers a precise method to study the global sources and sinks of these halogenated compounds that are of considerable importance to our understanding of stratospheric ozone destruction.
本文介绍了在卤代甲烷CH(3)Cl、CH(3)Br、CH(3)I和甲硫醇(CH(3)SH)的生物生成、生物降解和非生物反应研究中，用于测定其δ(13)C的气相色谱/质谱/同位素比率质谱(GC/MS/IRMS)方法。气相色谱参数的优化使得能够从单个样品中鉴定和定量CO(2)、O(2)、CH(3)Cl、CH(3)Br、CH(3)I和CH(3)SH，同时还能对每种卤代甲烷和甲硫醇的δ(13)C进行同步测量。随着质量增加(分别为CH(3)Cl、CH(3)Br、CH(3)I)，卤代甲烷标准品δ(13)C测量的精密度降低(分别为±0.3‰、±0.5‰和±1.3‰)。鉴于生物生成、生物降解和一些化学(非生物)反应过程中的碳同位素效应可达100‰，稳定同位素分析为研究这些对我们理解平流层臭氧破坏具有重要意义的卤代化合物的全球源汇提供了一种精确方法。
