Somboot Wasin, Jakmunee Jaroon, Kanyanee Tinakorn
Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Talanta. 2017 Aug 1;170:298-305. doi: 10.1016/j.talanta.2017.04.015. Epub 2017 Apr 9.
In this work, a homemade direct current (DC) conductivity detector as an alternative cost-effective detection device has been fabricated and investigated to use in flow analysis system. Under the selected appropriate conditions of flow system, the electrolysis of a carrier stream at the conductivity detector was negligible and provides well-defined signal. The cost-effective DC conductivity detector was demonstrated to couple with gas diffusion flow injection system for determination of dissolved inorganic carbon (DIC) in water. The method is based on the conversion of DIC (dissolved CO, HCO and CO) presented in the injected sample to carbon dioxide in an acidic donor stream and then CO gas diffuses through a hydrophobic porous membrane to an acceptor stream. As a result, the change of conductivity signal was observed corresponding to DIC concentration. A linear calibration range of DIC in 1.0-10mmolL, with limit of detection of 70µmolL, repeatability of <3% RSD and 15 injections h sample throughput can be obtained. This method was applied for DIC determination in natural water.
在本工作中，已制备并研究了一种自制的直流（DC）电导检测器，作为一种经济高效的替代检测装置，用于流动分析系统。在选定的合适流动系统条件下，电导检测器中载流的电解可忽略不计，并能提供明确的信号。已证明这种经济高效的直流电导检测器可与气体扩散流动注射系统联用，用于测定水中的溶解无机碳（DIC）。该方法基于将注入样品中存在的DIC（溶解的CO、HCO和CO）在酸性供体流中转化为二氧化碳，然后CO气体通过疏水多孔膜扩散到受体流中。结果，观察到与DIC浓度相对应的电导信号变化。DIC的线性校准范围为1.0 - 10mmol/L，检测限为70µmol/L，相对标准偏差（RSD）<3%的重复性以及每小时15次进样的样品通量均可实现。该方法已应用于天然水中DIC的测定。
