Departamento de Química Analítica, Facultade de Ciencias, Universidade da Coruña, Campus da Zapateira, E-15071 A Coruña, Spain.
J Chromatogr A. 2012 Jul 27;1248:55-9. doi: 10.1016/j.chroma.2012.05.099. Epub 2012 Jun 7.
A quick, miniaturized and on-line method has been developed for the determination in water of the predominant homologue of benzalkonium chloride, dodecyl dimethyl benzyl ammonium chloride or lauralkonium chloride (C(12)-BAK). The method is based on the formation of an ion-pair in both in-tube solid-phase microextraction (IT-SPME) and capillary liquid chromatography. The IT-SPME optimization required the study of the length and nature of the stationary phase of capillary and the processed sample volume. Because to the surfactant character of the analyte both, the extracting and replacing solvents, have played a decisive role in the IT-SPME optimized procedure. Conditioning the capillary with the mobile phase which contains the counter ion (acetate), using an organic additive (tetrabutylammonium chloride) added to the sample and a mixture water/methanol as replacing solvent (processed just before the valve is switched to the inject position), allowed to obtain good precision of the retention time and a narrow peak for C(12)-BAK. A reversed-phase capillary based TiO(2) column and a mobile phase containing ammonium acetate at pH 5.0 for controlling the interactions of cationic surfactant with titania surface were proposed. The optimized procedure provided adequate linearity, accuracy and precision at the concentrations interval of 1.5-300 μg L(-1) .The limit of detection (LOD) was 0.5 μg L(-1) using diode array detection (DAD). The applicability of proposed IT-SPME-capillary LC method has been assessed in several water samples.
已经开发出一种快速、微型化和在线方法，用于测定水中苯扎氯铵、十二烷基二甲基苄基氯化铵或月桂基氯化铵（C(12)-BAK）的主要同系物。该方法基于在管内固相微萃取（IT-SPME）和毛细管液相色谱中形成离子对。IT-SPME 的优化需要研究毛细管的固定相的长度和性质以及处理的样品体积。由于分析物的表面活性剂特性，萃取和替换溶剂都在优化的 IT-SPME 程序中发挥了决定性作用。用含有反离子（乙酸盐）的流动相对毛细管进行预处理，在样品中加入有机添加剂（四丁基氯化铵），并将水/甲醇混合物用作替换溶剂（仅在切换到进样位置之前处理），这使得 C(12)-BAK 的保留时间具有良好的精密度和较窄的峰。提出了基于 TiO(2)的反相毛细管柱和含乙酸铵的 pH 5.0 的流动相，以控制阳离子表面活性剂与二氧化钛表面的相互作用。在 1.5-300 μg L(-1) 的浓度范围内，优化的程序提供了足够的线性度、准确性和精密度。使用二极管阵列检测（DAD），检测限（LOD）为 0.5 μg L(-1)。该 IT-SPME-毛细管 LC 方法的适用性已在几种水样中进行了评估。
