Optimization and validation of a capillary electrophoresis methodology for inorganic anions in atmospheric aerosol samples

Optimization and validation of a method for the determination of inorganic anions, such as chloride, nitrate, sulphate, fluoride and phosphate, in atmospheric particulate matter is described. Ultrasonic extraction followed by CE, using CTAB as EOF modifier, has been established for this separation using chromate as visualization reagent for the indirect UV/vis detection. Optimization of the experimental chemical conditions (pH, surfactant concentration, chromate concentration and acetonitrile concentration) and instrumental parameters (temperature, applied voltage and injection time) is described. Linear calibrations plots are obtained for the five ions, with detection limits in the high ng/mL range. A standard reference material, SRM 1648 Urban Particulate Matter, has been used to validate the proposed method. Satisfactory reproducibility and acceptable agreement to the matter atmospheric samples has been found (recoveries ranging from 86 to 96%). Application to real particulate matter atmospheric samples, collected on high volume samplers from the air quality surveillance network of Extremadura, southwest Spain, is shown.