Development of a Compound-Specific Isotope Analysis Method for Atmospheric Formaldehyde and Acetaldehyde
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- 作者：Sheng Wen ; Yanli Feng ; Yingxin Yu ; Xinhui Bi ; Xinming Wang ; Guoying Sheng ; Jiamo Fu ; and Ping'an Peng
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：August 15, 2005
- 年：2005
- 卷：39
- 期：16
- 页码：6202 - 6207
- 全文大小：108K
- 年卷期：v.39,no.16(August 15, 2005)
- ISSN：1520-5851
文摘
A novel method determining compound-specific carbonisotopic compositions for atmospheric formaldehyde andacetaldehyde in ppb or sub-ppb levels by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is presented. Atmospheric carbonyls are collectedusing the conventional 2,4-dinitrophenylhydrazine (DNPH)derivatization method, and their 
13C values are calculatedbased on stoichiometric mass balance after measuringthe carbon isotopic compositions of the carbonyl-DNPHderivatives and DNPH, respectively. Using formaldehyde,acetaldehyde, and DNPH standards with their 13C valuespredetermined, the 13C fractionation is evaluated forderivatization processes both in solutions and in simulationexperiment of atmospheric sampling. In these twoderivatization systems, through reduplicate 13C analysis,good reproducibility of the derivertization process is foundwith an average error of less than 0.5”, and the differencesbetween the predicted and the measured 13C valuesrange from -0.18 to 0.49”, indicating that the derivatizationprocess introduces no isotopic fractionation for bothformaldehyde and acetaldehyde. Thus, the 13C values ofthe original underivatized carbonyls can be accuratelycalculated through mass balance equation. Using the methoddeveloped, preliminary tests of atmospheric formaldehydeand acetaldehyde at two urban sites were conductedand revealed significant differences of their isotopiccompositions, implying possible application of the methodin helping us understand the primary emission, secondaryformation, or removal processes of carbonyls in theatmosphere.
13C values are calculatedbased on stoichiometric mass balance after measuringthe carbon isotopic compositions of the carbonyl-DNPHderivatives and DNPH, respectively. Using formaldehyde,acetaldehyde, and DNPH standards with their 13C valuespredetermined, the 13C fractionation is evaluated forderivatization processes both in solutions and in simulationexperiment of atmospheric sampling. In these twoderivatization systems, through reduplicate 13C analysis,good reproducibility of the derivertization process is foundwith an average error of less than 0.5”, and the differencesbetween the predicted and the measured 13C valuesrange from -0.18 to 0.49”, indicating that the derivatizationprocess introduces no isotopic fractionation for bothformaldehyde and acetaldehyde. Thus, the 13C values ofthe original underivatized carbonyls can be accuratelycalculated through mass balance equation. Using the methoddeveloped, preliminary tests of atmospheric formaldehydeand acetaldehyde at two urban sites were conductedand revealed significant differences of their isotopiccompositions, implying possible application of the methodin helping us understand the primary emission, secondaryformation, or removal processes of carbonyls in theatmosphere.