A novel method for the analysis of benzimidazole residues in water samples by capillary electrochromatography-UV detection (290\u00a0nm), using laboratory-made packed columns is presented. Capillaries (25\u00a0cm packed length\u00d775\u00a0\u00b5m inner diameter, 34\u00a0cm total length, 25.5\u00a0cm effective capillary length) were packed with C18 particles (5\u00a0\u00b5m, 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 42\u00a0MPa. 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 7\u00a0V 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 (1\u00a0mM, pH 6.5), a separation voltage of 25\u00a0kV and a temperature of 25\u00a0\u00b0C. In addition, a combined hydrodynamic-electrokinetic injection mode was considered and samples were injected for 75\u00a0s under a voltage of 12.5\u00a0kV and a pressure of 11.5\u00a0bar. 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.<\/p>\n
This method was applied to different water samples, obtaining satisfactory results in terms of linearity (R2<\/sup>\u22650.990), repeatability (RSD\u22641.2%), reproducibility (RSD\u22642.2%) and trueness (R\u226587.7%). Detection and quantification limits were lower than 2.8\u00a0\u00b5g\u00a0L\u22121<\/sup> and 9.3\u00a0\u00b5g\u00a0L\u22121<\/sup>, respectively.<\/p>\n","protected":false},"excerpt":{"rendered":" A novel method for the analysis of benzimidazole residues in water samples by capillary electrochromatography-UV detection (290\u00a0nm), using laboratory-made packed columns is presented. Capillaries (25\u00a0cm packed length\u00d775\u00a0\u00b5m inner diameter, 34\u00a0cm total length, 25.5\u00a0cm effective capillary length) were packed with C18 … Continue reading