Simultaneous Determination of Nonsteroidal Anti-Inflammatory Drugs in Aqueous Samples Using Dispersive Liquid-Liquid Microextraction and HPLC Analysis

A simple, effective, and environmentally friendly sample preparation method was developed by using dispersive liquid-liquid microextraction prior to high-performance liquid chromatography analysis for the extraction/ concentration and assay of nonsteroidal anti-inflammatory drugs (NSAIDs), including indoprofen, ketoprofen, naproxen, diclofenac, ibuprofen, mefenamic acid, and tolfenamic acid, from an aqueous sample. The extraction conditions were optimized with respect to several experimental parameters (dispersive solvent, extraction solvent, pH, salt additive, and concentration) for the simultaneous extraction and analysis of NSAIDs by the response surface methodology based on the central composite design method. The limit of detection and limit of quantitation of the spiked sample were in the concentration range of 0.65-1.3 and 2.2-4.4 mu g/L, respectively. The accuracy and precision in the working range were 85-106% and 0.5-10.4% (relative standard deviation), respectively. The linear equations for quantitative analysis were in the concentration range of 0.5-5.0 mu g/L with correlation coefficients (R-2 = 0.9990-0.9996).