Portet F I, Treiner C, Desbène P L
Université de Rouen, Laboratoire d'Analyse des Systèmes Organiques Complexes, UPRES EA 2659, IRCOF et IFRMP, Evreux, France.
J Chromatogr A. 2000 May 5;878(1):99-113. doi: 10.1016/s0021-9673(00)00225-9.
The aim of this work was to simultaneously analyse mixtures of a polydisperse polyethylene oxide (PEO) nonionic surfactant and an anionic surfactant (sodium dodecylsulphate, SDS) in water containing sodium chloride in order to quantify trace amounts of these mixtures after their adsorption at water-solid interfaces. A fractional factorial design was then used to optimise the separation by ion-pair reversed-phase liquid chromatography as a function of six factors: the chain length of the tetraalkylammonium salt used as ion-pairing reagent which varied from methyl (C1) to n-propyl (C3); the concentration of this ion-pairing salt; the acetonitrile percentage in water used as organic modifier; the flow-rate; the temperature of analysis and also the sodium chloride concentration. The factorial design enabled in a limited number of analyses, not only to determine which factors had significant effects on retention times or on resolution between a pair of nonionic oligomers, but also to modelize and then find the interesting and rugged area where this resolution was optimal as well as the conditions where time of analysis was not prohibitive. After optimisation of HPLC analysis, we used a trace enrichment procedure to quantify very low concentrations of SDS and C12E9 polydisperse PEO in water. A C18 cartridge and a strong anionic exchange cartridge were coupled and the conditions of elution were optimised in order to obtain concentrated samples which were injected in the same eluent than the HPLC mobile phase. Under such conditions, we were able to quantify, in a single run, mixtures of anionic and nonionic surfactants at concentrations as low as 3.6 microg l(-1) for SDS and 2.5 microg l(-1) for each PEO oligomer in water.
这项工作的目的是同时分析聚环氧乙烷（PEO）多分散非离子表面活性剂与阴离子表面活性剂（十二烷基硫酸钠，SDS）在含有氯化钠的水中的混合物，以便在它们吸附于水 - 固界面后对这些混合物的痕量进行定量。然后采用分数析因设计来优化离子对反相液相色谱分离，该分离是六个因素的函数：用作离子对试剂的四烷基铵盐的链长，从甲基（C1）到正丙基（C3）变化；该离子对盐的浓度；用作有机改性剂的水中乙腈的百分比；流速；分析温度以及氯化钠浓度。析因设计使得在有限次数的分析中，不仅能够确定哪些因素对保留时间或一对非离子低聚物之间的分离度有显著影响，而且能够进行建模，进而找到分离度最佳的有趣且稳健的区域以及分析时间不冗长的条件。在优化高效液相色谱分析后，我们采用痕量富集程序来定量水中极低浓度的SDS和C12E9多分散PEO。将一个C18柱和一个强阴离子交换柱联用，并优化洗脱条件以获得浓缩样品，这些样品被注入与高效液相色谱流动相相同的洗脱液中。在这样的条件下，我们能够在一次运行中定量水中阴离子和非离子表面活性剂的混合物，SDS的浓度低至3.6 μg l⁻¹，每种PEO低聚物的浓度低至2.5 μg l⁻¹。
