Nesterenko Pavel N, Haddad Paul R, Hu Wenzhi
Department of Chemistry, Moscow State University, Vorob'evy Gory GSP-3, Moscow 119899, Russia.
J Chromatogr A. 2003 Feb 7;986(2):263-73. doi: 10.1016/s0021-9673(02)02008-3.
A further investigation of a chromatographic system allowing determination of hydrogen ions is reported. For this purpose an octadecylsilica column dynamically modified with sodium dodecylsulfate (SDS) or lithium dodecylsulfate (LDS) was used as stationary phase and a slightly acidified electrolyte (usually KCl)-SDS solution was used as the eluent. The concentration of SDS, KCl and the acidity of the eluent affected the structure of aggregates formed by the molecules of dodecylsulfate at the surface of the stationary phase. These aggregates of dodecylsulfate were found to be responsible for the appearance of a chromatographic peak attributed to the presence of H3O+ ions in a sample. Other cations in the sample could be separated in the same manner, permitting the simultaneous separation of monovalent cations from H3O+. The detection limit for H3O+ ions was 2.25 x 10(-6) M using an eluent comprising 0.3 mM LDS, 50.0 mM KCl and 0.10 mM H2SO4. The proposed method is shown to be applicable for the determination of free H3O+ ions in aqueous solutions of strong acids.
报道了一种用于测定氢离子的色谱系统的进一步研究。为此，使用用十二烷基硫酸钠（SDS）或十二烷基硫酸锂（LDS）动态改性的十八烷基硅胶柱作为固定相，并使用微酸化的电解质（通常为KCl）-SDS溶液作为洗脱液。SDS、KCl的浓度以及洗脱液的酸度影响了十二烷基硫酸盐分子在固定相表面形成的聚集体结构。发现这些十二烷基硫酸盐聚集体导致了归因于样品中H3O+离子存在的色谱峰的出现。样品中的其他阳离子可以以相同方式分离，从而实现一价阳离子与H3O+的同时分离。使用包含0.3 mM LDS、50.0 mM KCl和0.10 mM H2SO4的洗脱液时，H3O+离子的检测限为2.25×10（-6）M。所提出的方法被证明适用于测定强酸水溶液中的游离H3O+离子。
