Sulfonated polystyrene nanospheres from waste sources for the extraction of sulfonamide antibiotics from complex matrices

A next-generation sorbent phase is introduced based on recycled polystyrene microspheres sulfonated with sulfuric acid and its application to the extraction of four representative sulfonamides (i.e., sulfanilamide, sulfaguanidine, sulfadiazine, and sulfamerazine) from biological matrices. The variables related to the sulfonation process and those affecting the extraction process have been evaluated. The in-syringe miniaturized dispersive solid-phase extraction method coupled to liquid chromatography-tandem mass spectrometry provided limits of detection of 0.8 µg L− 1 for sulfaguanidine in urine to 32 µg L− 1 for sulfanilamide in saliva. The precision, expressed as relative standard deviation has been evaluated at four concentration levels both intra-day and inter-day, being lower than 18.3 and 14.3% at the lower limit of detection, respectively. The accuracy, calculated with spiked urine and saliva samples and expressed as relative recovery, ranged from 86.4 to 108.5%. This strategy integrates sustainable waste recovery with the development of a high-performance, low-impact adsorbent, employing recycled materials (such as syringes and frits) to create a nearly zero-waste extraction system. This combination of recycling, analytical performance, and sustainability supports the evolution of environmental analysis toward a “white circular” model, seamlessly merging Green Science with robust analytical standards.