Liu Shuai, Pan Zhen, Liang Ying, Li Feng, Breadmore Michael C, Zhang Min
School of Life and Environmental Sciences, Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, Guilin University of Electronic Technology, Guilin, Guangxi, 541004, China.
School of Life and Environmental Sciences, Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, Guilin University of Electronic Technology, Guilin, Guangxi, 541004, China.
J Chromatogr A. 2021 Jan 25;1637:461791. doi: 10.1016/j.chroma.2020.461791. Epub 2020 Dec 8.
An on-site ion analyzer based on capillary electrophoresis with pressure-driven flow through injection and capacitively coupled contactless conductivity detection has been developed for field monitoring of cations and anions in environmental waters. Automated time-pressure based hydrodynamic injection provides stable pL-nL scale injection (RSD = 1.96%, n = 30). A mixture of 400 mM Bis-Tris, 400 mM MOPS and 2 mM 18-crown-6 is used as the background electrolyte to provide repeatable separations. A proprietary hydrophilic coated 25 μm id capillary is used to suppress the electroosmotic flow. Separations of anions (Cl, NO, NO, SO, F and PO) and cations (NH, K, Na, Ca and Mg) are achieved by switching the polarity of the high voltage power supply in two individual runs. Signal fluctuations caused by the temperature or viscosity changes in on-site monitoring are corrected by on-line introduction of internal standards. RSDs of the migration time and the corrected peak height over ~35 h and 350 analysis cycles are <4.06%. The LODs of inorganic ions are in the range of 2.1 μM (K) to 6.8 μM (PO). The feasibility for on-site water monitoring with this system has been validated by a standard Ion chromatography method with comparable results obtained.
基于毛细管电泳的现场离子分析仪已被开发出来，该分析仪采用压力驱动流动进样和电容耦合无接触电导检测，用于现场监测环境水体中的阳离子和阴离子。基于时间压力的自动流体动力进样可提供稳定的皮升-纳升量级进样（相对标准偏差=1.96%，n=30）。使用400 mM Bis-Tris、400 mM MOPS和2 mM 18-冠-6的混合物作为背景电解质，以实现可重复的分离。使用一种专有的亲水涂层内径25μm的毛细管来抑制电渗流。通过在两次单独运行中切换高压电源的极性，实现阴离子（Cl、NO、NO、SO、F和PO）和阳离子（NH、K、Na、Ca和Mg）的分离。通过在线引入内标来校正现场监测中由温度或粘度变化引起的信号波动。在约35小时和350个分析周期内，迁移时间和校正峰高的相对标准偏差<4.06%。无机离子的检测限在2.1μM（K）至6.8μM（PO）范围内。该系统用于现场水质监测的可行性已通过标准离子色谱法得到验证，获得了可比的结果。
