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Poly(acrylamide-co-itaconic acid) (PAAmIA) and poly(acrylic acid-co-itaconic acid) (PAAIA) copolymeric hydrogels were prepared with different compositions via free-radical polymerization. Ethylene glycol dimethacrylate (EGDMA) was used as an original crosslinker for these monomers. Gelation percentages of the monomers were studied in detail and it was found that addition of IA into the monomer mixture decreased the gelation percentage. The variation in swelling values (%) with time, temperature, and pH was determined for all hydrogels. PAA, which is the most swollen hydrogel, has the swelling percentage value of 2000% at pH ¼ 7.4, 378C. Swelling behaviors were explained with detailed SEM micrographs, which show the morphologic differences between dry and swollen hydrogels.

A nanostructured silver-aniline modified pencil electrode obtained by applying experimental design and optimization was developed for the differential pulse stripping voltammetric quantification of acetaminophen in the pharmaceutical products, tablet and syrup. The electrode development process was performed by the modification of PGE with aniline using CV procedure and the reduction of silver nanoparticle on the polyaniline modified PGE. As a result, a new electrode system consisting of a nanostructured silverpolyaniline modified pencil graphite electrode (AgNS-PA-PGE) was obtained to reach a well-defined and higher peak current for the analysis of the related drug. The calibration curve was found linear in the range of 5 × 10 −8 -8 × 10 −7 M for acetaminophen. The validity and applicability of the proposed voltammetric method was tested by analyzing independent validation samples. It was observed that the proposed voltammetric approach for the real tablet and syrup samples gave successful analysis results.

An electrochemical biosensor was developed for the determination of Escherichia coli (E. coli) in water. For this purpose, silver‐gold core‐shell (Ag@Au) bioconjugates and anti‐E. coli modified PS‐microwells were designed in a sandwich‐type format in order to obtain higher sensitivity and selectivity. Ag@Au bimetallic nanoparticles were synthesized by co‐reduction method. The core‐shell formation was analyzed by using UV‐Vis spectroscopy and transmission electron microscopy. Biotin labeled anti‐E. coli antibodies were coupled with Ag@Au nanoparticles to form bioconjugates. The electrochemical immunosensor was prepared by immobilizing anti‐E. coli on polystyrene (PS)‐microwells via chemical bonding. These modified microwells were identified with X‐ray photoelectron spectroscopy and surface enhanced Raman spectroscopy. E. coli was sandwiched between Ag@Au bioconjugates and anti‐E. coli on PS‐microwells at different concentrations. The relationship between the E. coli concentration and stripping current of gold ions (Au3+) were investigated by square wave anodic stripping voltammetry at pencil graphite electrode. The proposed method can provide some advantages such as lower detection limit and shorter detection time. The electrochemical response for the immunosensor was linear with the concentration of the E. coli in the range of 101 and 105 cfu/mL with a limit of detection 3 cfu/mL. The procedure maintains good sensitivity and repeatability and also offers utility in the fields of environmental monitoring and clinical diagnosis.

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