Evaluation of strong cation-exchange polymers for the determination of drugs by solid-phase extraction–liquid chromatography–tandem mass spectrometry

• We prepare eight different strong-cation exchange (SCX) materials.
• The new SCX materials are evaluated in SPE/LC–MS/MS.
• The materials are evaluated in terms of recovery and matrix effect.
• A selective method to determine basic drugs in sewage samples is developed.

This paper presents eight distinct strong cation-exchange resins, all of which were derived from precursor resins that had been synthesised using either precipitation polymerisation or non-aqueous dispersion polymerisation. The precursor resins were transformed into the corresponding strong cation-exchange resins by hypercrosslinking followed by polymer analogous reactions, to yield materials with high specific surface areas and strong cation-exchange character. These novel resins were then evaluated as strong cation-exchange (SCX) sorbents in the solid-phase extraction (SPE) of a group of drugs from aqueous samples. Following preliminary experiments, the two best-performing resins were then evaluated in solid-phase extraction–liquid chromatography–tandem mass spectrometry (SPE/LC–MS/MS) to determine a group of drugs from sewage samples. In general, use of these sorbents led to excellent recovery values (75–100%) for most of the target drugs and negligible matrix effects (ME) (<20% ion suppression/enhancement of the analyte signal), when 50 mL and 25 mL of effluent and influent sewage water samples, respectively, were percolated through the resins. Finally, a validated method based on SPE/LC–MS/MS was used to quantify the target drugs present in different sewage samples.