A polyacrylate-based biomaterial for improved sample treatment: Application towards multiclass extraction of steroid hormones in drinking water and different milk samples

The original evaluation of a porous polymeric biomaterial as sorbent phase for analytical sample preparation is presented. The apolar nature of the base butyl acrylate-based polymer was tailored by embedding hydrophilic moieties of either 4-hydroxybutylacrylate or polyethyleneglycole mono methacrylate. This allowed, through the one-pot approach, to prepare hydrophilic-lipophilic balanced materials, which were then tested for the multiclass extraction of steroids from water and milk samples. As demonstrated through packed-cartridge solid-phase extraction (SPE), increasing the sorbent hydrophilicity improved the sorption affinity for the less lipophilic steroids, i.e. glucocorticoids, achieving quantitative uptake for all the probe contaminants on the PEG-modified polymer. The latter was applied to recovery tests at the ng/L level in tap and drinking water samples (25 mL), observing a complete elution in a single fraction of ethanol, thus achieving recovery in the range 60–125 % for most analytes (inter-day RSD < 19 %, n = 3). Reusability tests in tap water demonstrated the durability of the polymer for five consecutive sorption/elution cycles, with unchanged performance. The same material was functional to the extraction/clean-up of the steroids in milk samples (1 mL), at the micrograms per litre level, without sample deproteinization, as proved by SPE in whole, partially skimmed and lactose-free dairy milk samples, and bottled infant formula milk. After sample loading and washing with 5 % v/v acetonitrile acidic aqueous solution, the analytes were single-step eluted in pure ethanol, obtaining recovery ranging from 50 to 110 % (inter-day RSD < 12 %, n = 3), and clear extracts to be analyzed by HPLC-MS/MS. The greenness assessment proved the sustainability of this SPE procedure.