Monser L, Adhoum N, Sadok S
Département de Chimie, Centre Urbain Nord, Institut National des Sciences Appliquées et de Technologie, B.P. 676, 1080 Tunis Cedex, Tunisia.
Talanta. 2004 Feb 6;62(2):389-94. doi: 10.1016/j.talanta.2003.08.008.
A novel gas diffusion-flow injection method has been developed for the rapid and sensitive determination of total inorganic carbon (TIC) in water. The method is based on the diffusion of CO(2) across gas permeable membrane from a donor stream containing 0.1M HCl to an acceptor stream of sodium acetate (10(-5)moll(-1) and pH 10). The CO(2) trapped in the acceptor stream passes through an electrochemical flow cell contains a tungsten oxide wire and a silver/silver chloride electrode, where it was sensitively detected. The parameters affecting the sensitivity of the electrode such as buffer concentration, pH, flow rate and injected volume were studied in detail. The electrode response was linear in the concentration range from 5 to 100mugml(-1) CO(3)(2-) with a correlation coefficient (R(2)) of 0.998. Precision (R.S.D.) was 1.42% for 20mugml(-1) standard solution of CO(3)(2-) (n=10). The detection limit was 0.20mugml(-1) CO(3)(2-). The method was evaluated by the injection of real natural water samples and an average recovery of 100.1% was obtained. The sampling rate was 30 samplesh(-1). The method is simple, feasible with satisfactory accuracy and precision and thus could be used for monitoring TIC in water.
已开发出一种新型气体扩散-流动注射法，用于快速灵敏地测定水中的总无机碳（TIC）。该方法基于二氧化碳从含0.1M盐酸的供体流通过气体渗透膜扩散到乙酸钠受体流（10⁻⁵mol l⁻¹，pH 10）中。捕获在受体流中的二氧化碳通过一个包含氧化钨丝和银/氯化银电极的电化学流通池，在其中被灵敏检测。详细研究了影响电极灵敏度的参数，如缓冲液浓度、pH值、流速和进样体积。电极响应在5至100μg ml⁻¹碳酸根离子浓度范围内呈线性，相关系数（R²）为0.998。对于20μg ml⁻¹碳酸根离子标准溶液（n = 10），精密度（相对标准偏差）为1.42%。检测限为0.20μg ml⁻¹碳酸根离子。通过进样实际天然水样对该方法进行评估，平均回收率为100.1%。采样率为30个样品/小时。该方法简单、可行，准确度和精密度令人满意，因此可用于监测水中的总无机碳。
