Preparation and application of methacrylate-based cation-exchange monolithic columns for capillary ion chromatography.
Preparation and application of methacrylate-based cation-exchange monolithic columns for capillary ion chromatography.
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DOI：
10.1021/ac040079g
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发表时间：
2004-11
影响因子：
7.4
通讯作者：
Yuji Ueki;T. Umemura;Jinxiang Li;T. Odake;K. Tsunoda
中科院分区：
文献类型：
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作者：
Yuji Ueki;T. Umemura;Jinxiang Li;T. Odake;K. Tsunoda
以甲基丙烯酸缩水甘油酯（GMA）和二甲基丙烯酸乙烯酯（DMA）为单体，在250 μ m. d.熔融石英毛细管及其随后的基于环氧化物与1 M Na（2）SO（3）开环的磺化。通过改变含环氧基聚合物在Na（2）SO（3）溶液中的浸泡时间，可以轻松且可重复地将阳离子交换容量控制在高达300微当量/mL的范围内。通过分离常见阳离子如Na（+）、NH（4）（+）、K（+）、Mg（2+）和Ca（2+）的模型混合物来评价所制备的整体毛细管柱的色谱性能。例如，这些阳离子可以在15 cm长的阳离子交换整体柱（柱体积，7.4 μ L）上通过用10 mM CuSO（4）洗脱而很好地彼此分离，柱容量为150微当量/mL。该15 cm柱的压降在1 mm/s的正常线速度（3微升/分钟的流速）下为约1 MPa，阳离子的理论塔板数高于3000板/15 cm。这种基于GMA的阳离子交换整体柱可以承受至少10 mm/s的高线速度。在连续使用至少两周的时间内，未观察到选择性和分辨率的显著变化。提出了流速梯度洗脱的适用性和直接进样测定唾液中主要阳离子的可行性。
Polymer-based strong cation-exchange monolithic capillary columns with different capacities were constructed for ion chromatography by radical polymerization of glycidyl methacrylate (GMA) and ethylene dimethacrylate in a 250-microm-i.d. fused-silica capillary and its subsequent sulfonation based on ring opening of epoxides with 1 M Na(2)SO(3). The cation-exchange capacities can easily and reproducibly be controlled in the range of up to 300 microequiv/mL by changing the immersion time of the epoxy-containing polymer in the Na(2)SO(3) solution. The chromatographic performance of the produced monolithic capillary columns was evaluated through the separation of a model mixture of common cations such as Na(+), NH(4)(+), K(+), Mg(2+), and Ca(2+). As an example, these cations could be well separated from one another on a 15-cm-long cation-exchange monolithic column (column volume, 7.4 microL) with a capacity of 150 microequiv/mL by elution with 10 mM CuSO(4). The pressure drop of this 15-cm column was approximately 1 MPa at a normal linear velocity of 1 mm/s (a flow rate of 3 microL/min), and the numbers of theoretical plates for the cations were above 3000 plates/15 cm. This GMA-based cation-exchange monolithic column could withstand high linear velocities of at least 10 mm/s. Over a period of at least two weeks of continuous use, no significant changes in the selectivity and resolution were observed. The applicability of a flow rate gradient elution and the feasibility of direct injection determination of major cations in human saliva sample were also presented.