Analytical Chemistry Laboratories, La Trobe University, Victoria 3086, Australia.
Talanta. 2004 Feb 27;62(3):631-6. doi: 10.1016/j.talanta.2003.09.008.
A gas diffusion-flow injection system was developed for the determination of carbon dioxide in gaseous samples. The calibration was based on the use of either gaseous carbon dioxide or aqueous sodium carbonate standards. Gaseous carbon dioxide samples and gaseous or aqueous standards were injected directly into a donor stream of 1.0x10(-4)M H(2)SO(4). In the gas diffusion unit, carbon dioxide diffused through a PTFE membrane into an acceptor stream containing a mixed acid/base indicator. The absorbance of the acceptor stream was monitored spectrophotometrically at 554nm. The calibration plot was linear over the range of 5.00x10(2) to 1.27x10(4)mull(-1) with a sample throughput of 28h(-1) and 3.2% R.S.D. ([CO(2)]=2.37x10(3)mull(-1), n=12). The detection limit was determined as 2.50x10(2)mull(-1). The flow system was successfully applied to the analysis of several natural gaseous samples and the headspace of milk containers during storage. The flow injection results were found to be statistically indistinguishable at the 95% confidence level from those obtained by gas chromatography using thermal conductivity detection.
建立了一种用于气态样品中二氧化碳测定的气体扩散-流动注射系统。校准是基于使用气态二氧化碳或碳酸水溶液标准。气态二氧化碳样品和气态或水溶液标准直接注入到 1.0x10(-4)M H(2)SO(4)的供流中。在气体扩散单元中，二氧化碳通过 PTFE 膜扩散到含有混合酸碱指示剂的接受流中。在 554nm 处通过分光光度法监测接受流的吸光度。在 5.00x10(2)至 1.27x10(4)mull(-1)的范围内，校准曲线呈线性，样品通量为 28h(-1)，R.S.D.为 3.2%（[CO(2)]=2.37x10(3)mull(-1)，n=12）。检测限确定为 2.50x10(2)mull(-1)。该流动系统成功应用于几种天然气态样品和储存过程中牛奶容器顶空的分析。在 95%置信水平下，流动注射结果与使用热导率检测的气相色谱法得到的结果在统计学上无显著差异。
