Evaluation of the Sealed-tube Low-temperature Combustion Method for the 13C/12C and 2H/1H Ratio Determinations of Cellulose Nitrate

• 来源期刊: 中国化学（英文版）
• 学科: 化学
• 年，卷（期）: 2001,（11）
• 页码范围: 1089-1096
• 页数: 8页
• 分类号: O6
• 语种: 英文

摘要

Traditionalluy+suggested combusion time of 1 h at 550℃ withthe sealed-tube combustion method for deternining the 13C/12C ratio of cellulose nitrate or other nitrogen-containing components could produce large negative deviation up to 1%o.Three types of cellulose are used to ascertain possible causes.The presence of nitrous oxide (N2O) formed during combus tion is most likely responsible for this deviation. Prolongation of the combustion time (at least 5 h at 550℃) and intimate coatact between copper oxide and organic matter can greatly improve the analysis precision and effectively reduce this devi ation to an acceptable level. Regardless of scattered carbon isotope data, hydrogen isotope data are all reproducible within 2‰ when this method is coupled with the high temperaure uranium reduction method. Thus, care should be taken for deternining carbon and nitrogen isotope com,positions of nitrogen-conaining substances using the low temperature sealedtube combustion method.