强阳离子交换整体电渗泵流量影响因素研究

Study on influence factors of the flux for strong cation-exchange monolithic electroosmotic pump

采用丙烯酸,2-丙烯酰胺-2-甲基丙磺酸为功能单体,N,N’-亚甲基双丙烯酰胺为交联剂,正十二醇、1,4-丁二醇及二甲基亚砜为致孔剂,偶氮二异丁腈为引发剂在原位聚合,制备出了以丙烯酰胺类强阳离子交换整体柱为核心的电渗泵。在乙腈-磷酸盐二元流动相体系下,考察了驱动电压,有机调节剂,盐浓度,pH对该泵流量的影响。流量与驱动电压呈线性关系(0.9991);当有机调节剂乙腈的浓度低于70%时,固定相溶胀为主要因素,流量随乙腈浓度的增加而有下降的趋势,但随着有机调节剂浓度的增加(>70%),此时粘度起主要作用,流量开始缓慢地增加;随着磷酸盐浓度逐渐增加,流量随之降低;在pH 3～9范围内,流量基本上保持恒定。

A strong cation-exchange monolithic electroosmotic column was prepared inside the fused-silica capillary bypolymerization.The solution was consisted of acrylanide,2-acrylamido-2-methyl-1-propanesulfonicacid as a functional monomer,N,N＇-methylenebisacrylanide as a cross-linking agent,dimethyl sulphoxide and dodecanol,1,4-Butanediol as organic porogenic reagents and azobisisobutyronitrile as an initiator.The monolithic column was severed as a key part of electroosmotic pump.Effects of applied voltage,the concentrations of organic modifier and salt solution,pH value on the flux were investigated.A good linear relationship between the applied voltage and the flux was obtained（0.9991）.The concentration of the organic modifier（ACN）was less than 70%.The swelling degree of stationary phase played a main role,and the flux decreased with increase of the concentration of ACN.However,its concentration was more than 70%,at this time the viscosity of mobile phase was the main influence factor,the flux began to increase slightly.The flux decreased as the concentration of phosphate increased.pH value was in the range of 3~9,it did not exert a significant change in the flux.Satisfactory results were obtained through making comparisons between the influence factors and theoretical value.