Development of Hyphenated Analytical Instruments for Speciation analysis for Trace Elements

为发展微型高效液相色谱-电感耦合等离子体质谱、电感耦合等离子体质谱等联用仪器，新研制了各种类型的聚甲基丙烯酸酯类整体毛细管柱。以甲基丙烯酸缩水甘油酯和二甲基丙烯酸乙二酯为原料，在250μ的m-i.d.中进行自由基聚合，构建了强阳离子交换整体毛细管柱。用1M Na_2SO_3对环氧化物进行开环，得到熔融石英毛细管及其磺化产物。通过Na~+、NH_4~(2+)、K~+、Mg~(2+)和Ca~(2+)等常见阳离子对色谱柱的色谱学性能进行评价。例如，在容量为0.15mequiv/mL的15 cm色谱柱上，它们可以很好地分离，其中该15 cm色谱柱的压降约为1兆帕，法线速度为1 mm/S(流速为3μL/分钟)，阳离子的理论板数超过3,000板/15 cm。此外，该柱可以承受至少10 mm/S的高线速度。这种基于GMA的方法被扩展到制备强阴离子交换柱，其中通过环氧化物与烷基胺化合物的开环反应引入季铵基团，然后与苄基或烷基卤化物反应。通过甲基丙烯酸烷基酯和二甲基丙烯酸乙二醇酯的自由基聚合，制备了反相柱。此外，还利用这种基于GMA的方法开发了具有反相分离模式的电色谱柱。

Various types of polymethacrylate-based monolithic capillary columns were newly prepared for the development of hyphenated instruments such as micro-HPLC-ICP-MS and CEC-ICP-MS. Strong cation-exchange monolithic capillary columns were constructed for ion chromotography by radical polymerization of glycidyl methacrylate (GMA) and ethylene dimethacrylate in a 250-μm-i.d. fused silica capillary and its subsequent sulfonatiori based on ring opening of epoxides with 1 M Na_2SO_3. The chromotographic performance of the columns was evaluated through common cations such as Na^+,NH_4^+,K^+,Mg^<2+> and Ca^<2+>. For an example, they could be well separated from one another on a 15 cm column with a capacity of 0.15 mequiv/mL where the pressure drop of this 15 cm column was ca. 1 MPa at a normal linear velocity of 1 mm/s (a flow rate of 3 μL/min) and the number of theoretical plates for the cations was above 3000 plates/15 cm. Moreover, this column could withstand high linear velocities of at least 10 mm/s. This GMA-based approach was extended to the preparation of strong anion-exchange columns where quaternary ammonium groups were introduced by the ring opening reaction of the epoxides with alkylamine compounds followed by the reaction with benzyl or alkyl halides. Reversed-phase columns were also prepared by radical polymerization of various alkyl methacrylates and ethylene glycol dimethacrylate. Moreover, CEC columns which show reversed-phase separation modes were also developed with this GMA-based approach.