Latex-coated polymeric monolithic ion-exchange stationary phases. 1. Anion-exchange capillary electrochromatography and in-line sample preconcentration in capillary electrophoresis
Latex-coated polymeric monolithic ion-exchange stationary phases. 1. Anion-exchange capillary electrochromatography and in-line sample preconcentration in capillary electrophoresis
复制标题
DOI：
10.1021/ac048748d
复制
发表时间：
2005-01-15
影响因子：
7.4
通讯作者：
Haddad, PR
中科院分区：
文献类型：
--
作者：
Hutchinson, JP;Zakaria, P;Haddad, PR
在直径为50-533微米的熔融硅毛细管内合成了一种磺化甲基丙烯酸酯整体聚合物。并涂有直径65 nm的全功能化季铵胶乳颗粒(AS18，Dionex Corp.)形成阴离子交换固定相。该固定相用于75um-i.d.中无机阴离子的离子交换毛细管电层析。毛细管采用Tris/高氯酸盐电解液，在195 nm处进行直接UV检测。7种无机阴离子(溴、硝酸盐、碘化物、碘酸盐、溴酸盐、硫氰酸盐、铬酸盐)在90 S的时间内得到分离，洗脱顺序表明离子交换和电泳法都有助于分离机理。分离效率高达1.66×10(5)板数m(-1)，整体柱在高达62兆帕的压力下稳定。另一块涂着乳胶的巨型石碑，上面有250个妈妈的身份证。通过将毛细管连接到分离毛细管来用于在线预浓缩，在分离毛细管中，使用阳离子聚合物或阳离子乳胶粒子的涂层逆转了EOF。将几个毛细管体积的样品加载到预富集整体柱上，然后以瞬时等渗梯度从整体柱上洗脱被分析物(无机阴离子)，然后在分离毛细管中进行电泳法分离。获得了溴化物、亚硝酸盐、硝酸盐和碘化物混合水溶液的线性校正曲线。当样品基质中含有高水平的氯化物时，除碘以外的所有分析物的回收率都显著降低。将该方法用于海水中碘的测定，在信噪比为3的条件下，检出限为75 pM(9.5 ng/L)，相对标准偏差为1.1%，峰面积为2.7%(n=6)。碘化物被作为有效峰洗脱。分离效率为5.13×10(7)板m(-1)。这种聚焦对海水的重复分析是可以重现的。
A sulfortated methacrylate monolithic polymer has been synthesized inside fused-silica capillaries of diameters 50-533-mum i.d. and coated with 65-nm-diameter fully functionalized quaternary ammonium latex particles (AS18, Dionex Corp.) to form an anion-exchange stationary phase. This stationary phase was used for ion-exchange capillary electrochromatography of inorganic anions in a 75-mum-i.d. capillary with Tris/perchlorate electrolyte and direct UV detection at 195 nm. Seven inorganic anions (bromide, nitrate, iodide, iodate, bromate, thiocyanate, chromate) could be separated over a period of 90 s, and the elution order indicated that both ion exchange and electrophoresis contributed to the separation mechanism. Separation efficiencies of up to 1.66 x 10(5) plates m(-1) were achieved, and the monoliths were stable under pressures of up to 62 MPa. Another latex-coated monolith in a 250-mum-i.d. capillary was used for in-line preconcentration by coupling it to a separation capillary in which the EOF had been reversed using a coating of either a cationic polymer or cationic latex particles. Several capillary volumes of sample were loaded onto the preconcentration monolith, and the analytes (inorganic anions) were then eluted from the monolith with a transient isotachophoretic gradient before being separated by electrophoresis in the separation capillary. Linear calibration curves were obtained for aqueous mixtures of bromide, nitrite, nitrate, and iodide. Recoveries of all analytes except iodide were reduced significantly when the sample matrix contained high levels of chloride. The preconcentration method was applied to the determination of iodide in open ocean water and provided a limit of detection of 75 pM (9.5 ng/L) calculated at a signal-to-noise ratio of 3. The relative standard deviation for migration time and peak area for iodide were 1.1 and 2.7%, respectively (n = 6). Iodide was eluted as an efficient peak. yielding a separation efficiency of 5.13 x 10(7) plates m(-1). This focusing was reproducible for repeated analyses of seawater.