Optimization of diclofenac quantification from wastewater treatment plant sludge by ultrasonication assisted extraction

• Optimized method for the extraction of diclofenac from wastewater sludge samples.
• An easy-to-use and effective extraction method.
• The LOD and LOQ of the method were determined as 1 ng/g and 5 ng/g, respectively.
• Diclofenac does not accumulate in the sludge during wastewater treatment.

A rapid quantification method of diclofenac from sludge samples through ultrasonication assisted extraction and solid phase extraction (SPE) was developed and used for the quantification of diclofenac concentrations in sludge samples with liquid chromatography/tandem mass spectrometry (LC–MS/MS). Although the concentration of diclofenac in sludge samples taken from different units of wastewater treatment plants in Istanbul was below the limit of quantification (LOQ; 5 ng/g), an optimized method for sludge samples along with the total mass balances in a wastewater treatment plant can be used to determine the phase with which diclofenac is mostly associated. Hence, the results will provide information on fate and transport of diclofenac, as well as on the necessity of alternative removal processes. In addition, since the optimization procedure is provided in detail, it is possible for other researchers to use this procedure as a starting point for the determination of other emerging pollutants in wastewater sludge samples.