Preparation and application of methacrylate-based cation-exchange monolithic columns for capillary ion chromatography.
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.
Ueki
Yuji
Y
Department of Chemistry, Faculty of Engineering Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
Umemura
Tomonari
T
Li
Jinxiang
J
Odake
Tamao
T
Tsunoda
Kin-Ichi
K
D002411:Cation Exchange Resins / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D002852:Chromatography, Ion Exchange / Q000379:methods*; D004852:Epoxy Compounds / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry*; D012463:Saliva / Q000737:chemistry; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry; D013997:Time Factors
D002411:Cation Exchange Resins; D002412:Cations; D004852:Epoxy Compounds; D008689:Methacrylates; D012822:Silicon Dioxide; C004919:ethylene dimethacrylate; C007870:glycidyl methacrylate