Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelská 1, CZ-613 00 Brno, Czech Republic.
J Chromatogr A. 2010 Jul 30;1217(31):5116-23. doi: 10.1016/j.chroma.2010.06.017. Epub 2010 Jun 9.
Basic operation principles of a lightweight, low power, low cost, portable ion chromatograph utilizing open tubular ion chromatography in capillary columns coated with multi-layer polymeric stationary phases are demonstrated. A minimalistic configuration of a portable IC instrument was developed that does not require any chromatographic eluent delivery system, nor sample injection device as it uses gravity-based eluent flow and hydrodynamic sample injection adopted from capillary electrophoresis. As a detection device, an inexpensive commercially available capacitance sensor is used that has been shown to be a suitable substitute for contactless conductivity detection in capillary separation systems. The built-in temperature sensor allows for baseline drift correction typically encountered in conductivity/capacitance measurements without thermostating device. The whole instrument does not require any power supply for its operation, except the detection and data acquisition part that is provided by a USB port of a Netbook computer. It is extremely lightweight, its total weight including the Netbook computer is less than 2.5kg and it can be continuously operated for more than 8h. Several parameters of the instrument, such as detection cell design, eluent delivery systems and data treatment were optimized as well as the composition of eluent for non-suppressed ion chromatographic analysis of common inorganic cations (Na(+), NH(4)(+), K(+), Cs(+), Ca(2+), Mg(2+), transition metals). Low conductivity eluents based on weakly complexing organic acids such as tartaric, oxalic or pyridine-2,6-dicarboxylic acids were used with contactless capacitance detection for simultaneous separation of mono- and divalent cations. Separation of Na(+) and NH(4)(+) cations was optimized by addition of 18-crown-6 to the eluent. The best separation of 6 metal cations commonly present in various environmental samples was accomplished in less than 30min using a 1.75mM pyridine-2,6-dicarboxylic acid and 3mM 18-crown-6 eluent with excellent repeatability (below 2%) and detection limits in the low micromolar range. The analysis of field samples is demonstrated; the concentrations of common inorganic cations in river water, mineral water and snow samples were determined.
利用涂有多层聚合固定相的毛细管柱中的开管离子色谱法，展示了一种重量轻、功耗低、成本低、便携式的离子色谱仪的基本工作原理。开发了一种极简的便携式 IC 仪器配置，它不需要任何色谱洗脱液输送系统，也不需要进样装置，因为它使用基于重力的洗脱液流动和从毛细管电泳采用的流体进样。作为检测装置，使用了一种廉价的市售电容传感器，事实证明，它是毛细管分离系统中无接触电导率检测的合适替代品。内置温度传感器允许在没有恒温装置的情况下进行电导率/电容测量中通常遇到的基线漂移校正。整个仪器除了检测和数据采集部分需要 Netbook 计算机的 USB 端口提供电源外，其他部分无需电源即可运行。它非常轻巧，包括 Netbook 计算机在内的总重量不到 2.5 公斤，可以连续运行 8 小时以上。对仪器的几个参数（如检测池设计、洗脱液输送系统和数据处理）进行了优化，还优化了用于非抑制型离子色谱分析常见无机阳离子（Na(+)、NH(4)(+)、K(+)、Cs(+)、Ca(2+)、Mg(2+)、过渡金属）的洗脱液组成。使用基于弱配位有机酸（如酒石酸、草酸或吡啶-2,6-二羧酸）的低电导率洗脱液，并结合非接触电容检测，可同时分离单价和二价阳离子。通过在洗脱液中添加 18-冠-6 对 Na(+)和 NH(4)(+)阳离子进行了优化分离。使用 1.75mM 吡啶-2,6-二羧酸和 3mM 18-冠-6 洗脱液，在不到 30 分钟的时间内完成了 6 种常见金属阳离子的最佳分离，具有出色的重复性（低于 2%）和检测限在低微摩尔范围内。演示了现场样品的分析；测定了河水、矿泉水和雪样中常见无机阳离子的浓度。
