Optimization of a solidified floating organic drop microextraction procedure through an experimental design for the simultaneous determination of four non‐steroidal anti‐inflammatory drugs in river water

Abstract To simultaneously determine the non‐steroidal anti‐inflammatory drugs ketoprofen, nimesulide, diclofenac and ibuprofen in river water, a simple and cost‐effective solidified floating organic drop microextraction method coupled with high‐performance liquid chromatography was developed. Through multivariate optimization, the variables extracting volume, dispersive volume, sample pH and ionic strength were optimized by a full factorial design 2 4 and Doehlert matrix. The optimized experimental conditions were 30 μL of extracting solvent (1‐dodecanol), 300 μL of dispersive solvent (acetonitrile) and sample pH of 2. The optimized method showed low limits of detection (0.05 to 0.09 μg L −1 ), satisfactory recoveries (up to 118%) and enrichment factors ranging from 67 to 197. The optimized method applied in river water samples showed low matrix effects, making it possible to apply this method successfully for the quantification of four NSAIDs in river water samples.