Electrochemically grown imprinted polybenzidine nanofilm on multiwalled carbon nanotubes anchored pencil graphite fibers for enantioselective micro-solid phase extraction coupled with ultratrace sensing of d- and l-methionine

Simple and fast self-polymerization of benzidine using anodic exfloated graphene oxide nanosheet

Nowadays, researchers are looking for green synthesis methods of polymers that solve the disadvantages of polymerization with different initiators and traditional methods. In this work, the self-polymerization process of benzidine by anodic exfloated graphene oxide Nanosheet electrode (AEGO Nsh) is reported for the first time in the world. The self-polymerization of benzidine onto AEGO Nsh electrode was done by an easy and simple method by anodizing the graphite sheet followed by immersing the AEGO Nsh electrode inside the benzidine monomer dissolved in organic and inorganic acid media. The surface morphology of the self-polymerized benzidine (SPB) onto the AEGO Nsh (SPB/AEGO Nsh) electrode was investigated by phone camera and scanning electron microscope (FE-SEM) imaging. The chemical characterization of the SPB/AEGO Nsh electrode was verified through XPS and ATR-IR analysis. Additionally, the self-polymerization of benzidine onto AEGO Nsh electrodes was confirmed by electrochemical tests using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The results from these investigations unequivocally confirm the self-polymerization of benzidine onto the AEGO Nsh electrode.

Design of a pseudo stir bar sorptive extraction using graphenized pencil lead as the base of the molecularly imprinted polymer for extraction of nabumetone

Molecularly imprinted polymer (MIP) was synthesized through the coprecipitation method on the graphene oxide anchored pencil lead as a substrate for the first time and applied as an efficient sorbent for pseudo stir bar sorptive extraction of nabumetone. The extracted analyte was determined by a novel spectrophotometric method based on the aggregation of silicate sol-gel stabilized silver nanoparticles in the presence of the analyte. The synthesized polymer was characterized using Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Optimization of important parameters affecting the extraction efficiency was done using central composite design whereas the spectrophotometric method was optimized via one at a time variable. Under the optimal conditions, the calibration curve exhibited linearity in the concentration range of 1.5-20.0 μg L^-1. A limit of detection of 0.20 μg L^-1, an enhancement factor of 393 and relative standard deviations (at 10 μg L^-1, n = 6) of 4.6% and 8.1% for intra- and inter-day analysis were obtained. The developed procedure was successfully utilized for the quantification of traces of nabumetone in tap water and biological samples with the complex matrix including human urine and serum.

Pencil Graphite Electrodes: A Versatile Tool in Electroanalysis

Due to their electrochemical and economical characteristics, pencil graphite electrodes (PGEs) gained in recent years a large applicability to the analysis of various types of inorganic and organic compounds from very different matrices. The electrode material of this type of working electrodes is constituted by the well-known and easy commercially available graphite pencil leads. Thus, PGEs are cheap and user-friendly and can be employed as disposable electrodes avoiding the time-consuming step of solid electrodes surface cleaning between measurements. When compared to other working electrodes PGEs present lower background currents, higher sensitivity, good reproducibility, and an adjustable electroactive surface area, permitting the analysis of low concentrations and small sample volumes without any deposition/preconcentration step. Therefore, this paper presents a detailed overview of the PGEs characteristics, designs and applications of bare, and electrochemically pretreated and chemically modified PGEs along with the corresponding performance characteristics like linear range and detection limit. Techniques used for bare or modified PGEs surface characterization are also reviewed.

Application of nanocomposite-based sorbents in microextraction techniques: a review

This review provides a general overview of the recent trends for the preparation of nanocomposites and their applications in microextraction techniques.