Bar adsorptive microextraction (BAμE) coated with mixed sorbent phases-Enhanced selectivity for the determination of non-steroidal anti-inflammatory drugs in real matrices in combination with capillary electrophoresis

The present work proposes the application of bar adsorptive microextraction coated with mixed sorbent phases (n-vinylpyrrolidone and divinylbenzene polymers with strong and weak anion exchangers), combined with liquid desorption followed by capillary electrophoresis with diode array detection (BAμE(P_MIX)-LD/CE-DAD) for the determination of trace levels of non-steroidal anti-inflammatory drugs (NSAIDs: salicylic acid, mefenamic acid, diclofenac and naproxen as model compounds) in urine and water matrices. Assays performed on 25mL of water samples spiked at the 80.0μg/L level, yielded average recoveries between 86.6 and 104.% for all the NSAIDs under study using optimized experimental conditions. The proposed analytical methodology demonstrated suitable detection limits (0.3μg/L) and good linear dynamic ranges (2.5-320.0μg/L) with determination coefficients higher than 0.9981. By using the standard addition methodology, the present analytical approach was applied on urine and water samples, where good selectivity and sensitivity were achieved. The proposed method, which operated under the floating sampling technology, proved to be a suitable sorption-based static microextraction alternative for monitoring trace levels of NSAIDs in urine and water samples. The methodology showed to be easy to implement, demonstrating good reproducibility and robustness, allowing the possibility to choose the most selective sorbent, or mixed sorbent phases, according to the compounds of interest.