Tejada-Casado Carmen, Hernández-Mesa Maykel, Del Olmo-Iruela Monsalud, García-Campaña Ana M
Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, Granada, E-18071 Spain.
Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, Granada, E-18071 Spain.
Talanta. 2016 Dec 1;161:8-14. doi: 10.1016/j.talanta.2016.08.012. Epub 2016 Aug 2.
A novel method for the analysis of benzimidazole residues in water samples by capillary electrochromatography-UV detection (290nm), using laboratory-made packed columns is presented. Capillaries (25cm packed length×75µm inner diameter, 34cm total length, 25.5cm effective capillary length) were packed with C18 particles (5µm, non-encapped) following a high pressure packing procedure and using a compact steel unit designed for packing capillary columns. Acetone was employed as solvent to carry the particles through the capillary and pack it under a pressure of 42MPa. Outlet and inlet frits were made by sintering the particles of the stationary phase by heating the packed material with a nichrome ribbon connected to a 7V AC power supply. With the aim of achieving a good analytical performance, the variables that affected the separation were studied, using a mobile phase composition of 60:40 (v/v) acetonitrile/water containing ammonium acetate (1mM, pH 6.5), a separation voltage of 25kV and a temperature of 25°C. In addition, a combined hydrodynamic-electrokinetic injection mode was considered and samples were injected for 75s under a voltage of 12.5kV and a pressure of 11.5bar. Finally, the determination of benzimidazoles in water samples was accomplished by capillary electrochromatography using dispersive liquid-liquid microextraction as sample treatment. Variables affecting the extraction efficiency were optimized, using chloroform and ethanol as extraction and disperser solvents, respectively. This method was applied to different water samples, obtaining satisfactory results in terms of linearity (R≥0.990), repeatability (RSD≤1.2%), reproducibility (RSD≤2.2%) and trueness (R≥87.7%). Detection and quantification limits were lower than 2.8µgL and 9.3µgL, respectively.
本文介绍了一种使用实验室自制填充柱，通过毛细管电色谱-紫外检测（290nm）分析水样中苯并咪唑残留的新方法。毛细管（填充长度25cm×内径75µm；总长34cm，有效毛细管长度25.5cm）按照高压填充程序，使用专为填充毛细管柱设计的紧凑型钢制装置，填充C18颗粒（5µm，未封端）。以丙酮为溶剂，将颗粒通过毛细管并在42MPa的压力下进行填充。出口和入口筛板通过用连接到7V交流电源的镍铬带加热填充材料，烧结固定相颗粒制成。为了获得良好的分析性能，研究了影响分离的变量，流动相组成为60:40（v/v）乙腈/水，含醋酸铵（1mM，pH 6.5），分离电压为25kV，温度为25°C。此外，考虑了一种组合的流体动力学-电动进样模式，在12.5kV的电压和11.5bar的压力下进样75s。最后，通过使用分散液液微萃取作为样品处理的毛细管电色谱法完成水样中苯并咪唑的测定。分别使用氯仿和乙醇作为萃取剂和分散剂溶剂，优化了影响萃取效率的变量。该方法应用于不同的水样，在线性（R≥0.990）、重复性（RSD≤1.2%）、重现性（RSD≤2.2%）和准确性（R≥87.7%）方面均获得了满意的结果。检测限和定量限分别低于2.8µgL和9.3µgL。
