Farhana Syakirah Ismail, Siti Nurul Ain Md. Jamil, Peter A. G. Cormack, Luqman Chuah Abdullah, Sazlinda Kamaruzaman, and Rusli Daik. The Synthesis and Characterizations of Porous Thioamide-Sulfonated-Modified Poly(acrylonitrile-co-divinylbenzene-80) as a Potential Sorbent to Capture Polar Analytes. Sci. Adv. Mater. 2019, Vol. 11, No. 9

ABSTRACT Pharmaceuticals contain biologically active components that can pollute watercourses as a result of excretion from individuals and/or the uncontrolled release of residues from chemical plants, and this can pose a hazard to health. Pharmaceutical residues can persist at low concentrations in the environment, and thus may be potentially harmful to aquatic animals and to humans. The control and monitoring of such residues are therefore of prime interest by, for example, solid-phase extraction using solid sorbents to purify and preconcentrate the residues prior to their chemical analysis. In the present work, poly(acrylonitrile-co-divinylbenzene-80) sorbents were synthesized by varying the comonomer feed ratios under precipitation polymerization conditions to deliver a family of porous polymer microspheres. Acrylonitrile confers polar character onto the sorbents, and the acrylonitrile-derived nitrile groups can be chemically transformed via polymer-analogous reactions into thioamide and sulfonated residues which makes the sorbents even more suitable for the capture of polar analytes, including selected pharmaceuticals. The Fourier Transform Infrared (FTIR) spectroscopy confirmed the chemical modification of P33 copolymer with thiourea (TP33) and sulfonation (TP33-HSO3) due to the presence of strong peaks at ∼1050 cm−1 and ∼1154.47 cm−1 that were assigned to the stretching vibrations of C S group and SO3H group respectively. The Bruneaur-Emmett-Teller (BET) data demonstrated that the specific surface area had decreased significantly from 565.0 m2g−1 (P33) to 330.0 m2g−1 (TP33) and 5.9 m2g−1 (TP33-HSO3) after the chemical modifications were carried out with thiourea and sulphuric acid, respectively. The Scanning Electron Microscopy (SEM) analysis proved that the morphologies structure of the copolymer does not change much after chemical modification and sulfonation. The elemental analysis revealed that P33 had no sulfur content at all. The TP33 had 4.1% of sulfur content due to the chemical modification of the P33 with thiourea, while the amount of sulfur in TP33-HSO3 was the highest (5.8%) due to the sulfonation with sulfuric acid. The utility of the porous thioamide-sulfonated containing sorbents is demonstrated via the dispersion-solid phase extraction of mefenamic acid from aqueous media; mefenamic acid is an anthranilic acid derivative which is a potent, nonsteroidal anti-inflammatory drug which is found in environmental waters at low concentrations.