Liu S J, Tubino M
Instituto de Quimica, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6154, CEP 13083-970, Campinas, SP, Brazil.
Talanta. 1998 Nov;47(3):711-7. doi: 10.1016/s0039-9140(98)00123-4.
A flow-injection configuration based on a dual-phase gas-permeation system from a liquid donor to a gas acceptor stream with a thermistor flow-through detector is proposed for the direct analysis of the gas in the acceptor. This system was applied for the determination of carbon dioxide (in the form of carbonate) using the following chemical reaction: CO(2)(g)+2NH(3)(g)+H(2)O(g)=(NH(4))(2)CO(3)(s), with a linear response from 1x10(-3) to 50x10(-3) mol l(-1) of CO(3)(2-). Carbon dioxide was produced in the liquid donor and permeated into the gaseous acceptor stream of air/water vapor. The detection limit is 1x10(-3) mol l(-1) of carbonate, and a sampling frequency of 60 h(-1) is achieved with a relative standard deviation of 4.1% for replicate injections. The dual-phase gas-permeation flow-injection manifold, along with the membrane and phase separations, as well as the chemical reaction, provides enhanced selectivity when compared with the system employing a liquid acceptor stream, as serious interferents in this system, for instance, acetate and formate, among others, do not interfere in the proposed system.
本文提出了一种基于双相气体渗透系统的流动注射配置，该系统从液体供体流向气体受体流，并配有热敏电阻流通检测器，用于直接分析受体中的气体。该系统通过以下化学反应用于测定二氧化碳（以碳酸盐形式）：CO₂(g)+2NH₃(g)+H₂O(g)=(NH₄)₂CO₃(s)，对CO₃²⁻的线性响应范围为1×10⁻³至50×10⁻³ mol l⁻¹。二氧化碳在液体供体中产生并渗透到空气/水蒸气的气态受体流中。检测限为1×10⁻³ mol l⁻¹的碳酸盐，采样频率为60 h⁻¹，重复进样的相对标准偏差为4.1%。与采用液体受体流的系统相比，双相气体渗透流动注射歧管以及膜和相分离以及化学反应提供了更高的选择性，因为该系统中的严重干扰物，例如乙酸盐和甲酸盐等，在本系统中不会产生干扰。
