On-Column Preconcentration of Anti-Inflammatory Drugs in River Water by Anion-Selective Exhaustive Injection-Sweeping-MEKC

A high-sensitivity on-column preconcentration method, anion selective exhaustive injection (ASEI)-sweeping in micellar electrokinetic capillary chromatography (MEKC) has been developed for the analysis of non-steroidal anti-inflammatory drugs (NSAIDs): diclofenac sodium, ibuprofen, fenoprofen, naproxen, and ketoprofen in water samples. To achieve the best results of the ASEI-sweeping-MEKC method, conditions which affected preconcentration were examined, including the sodium dodecyl sulfate concentration, composition of the sample matrix, composition and injection length of the water plug, the concentration and the injection length of the high-conductivity buffer, and finally the sample injection time. Under the optimum stacking conditions the method was validated for the determination of the studied NSAIDs in river water samples with limits of detection ranging between 29 and 58 ng mL^?1, and without any previous sample pretreatment.