Graphene oxide/lysine composite – a potent electron mediator for detection of diazepam

Abstract

A graphene oxide/lysine (GO/lys) composite, synthesized using a very simple chemical method, has been used to modify a glassy carbon electrode for the voltammetric detection of diazepam.

Antifouling Strategies for Electrochemical Biosensing: Mechanisms and Performance toward Point of Care Based Diagnostic Applications

“…From a manufacturing perspective, composite nanocarbon systems including additives such as ionic liquids, coatings of mixed dispersions, or metal nanoparticles often involve long fabrication processes (i.e., 24 h refluxing, overnight drying, or material synthesis). 14,15,27 These additional treatment steps significantly complicate manufacturing when compared with bare screen-printed nanocarbon electrodes. To translate nanocarbon-based electrode sensing platforms into commercial products, research should be aimed at the detection of clinically relevant target analytes in complex biological media, while simultaneously enhancing the simplicity of manufacture of the sensing platform.…”

“…We generalize here that nanoengineered surfaces entail any surface with a nanomorphology or nanostructure. Nanoengineered surfaces can be comprised of a variety of different materials, namely, nanoporous/nanoparticle based metal surfaces (typically Au, Pt, and Ag) ,, and nanoporous carbon surfaces including carbon slurries, carbon nanotubes, or graphene and its derivatives (GO, rGO). ,,, The large variety of electrode material and morphological combinations has generated a vast amount of research toward the fabrication and evaluation of different nanoengineered electrode surfaces for electrochemical biosensing. Nanoengineered electrode surfaces benefit mainly from ultrahigh surface areas which enhance the magnitude of the electrochemical signal .…”

“…Nanostructured carbon electrodes are another form of nanoengineering technology with applications in POC diagnostics and drug detection. Nanocarbon surfaces are typically synthesized by dispersing a form of carbon (i.e., nanotubes, nanoparticles, and nanosheets) in acid solution. ,, Nanocarbon electrodes are commonly fabricated using screen-printing and related techniques using slurries of carbon within a volatile liquid carrier and, in many cases, a polymeric binder or other functional additive for enhancing the electrochemical signal sensitivity or providing additional antifouling characteristics, some of which include ionic liquid composites, or metal nanoparticles . In addition, there are also a great deal of commercially available screen-printed carbon-based electrodes with surfaces containing various types of nanomorphologies and are arguably the most commercially successful nanostructured electrodes to date.…”

“…When evaluating an antifouling strategy for a given biosensor platform, it is important to identify the target application and to use an appropriate sample matrix to assess fouling effects. The use of clean buffer solutions (i.e., PBS) at neutral pH levels, − single-molecule fouling solutions (i.e., bovine serum albumin (BSA) or fibrogen), − and even biological media which have been pretreated/diluted − are suitable for proof-of-concept experiments of antifouling capabilities; however they are not indicative of performance in complex biological media as highlighted by Ladd et al, in a study investigating the individual proteins in plasma responsible for surface fouling . The study concluded that in single-protein fouling solutions antifouling performance is drastically improved when compared with whole plasma.…”

Interpol review of controlled substances 2016–2019

“…Diazepam: 2016 Investigation of the solubility of diazepam in water plus tert-butyl alcohol solvent mixtures over temperature range [ 135 ]; voltammetric determination of diazepam using a bismuth modified pencil graphite electrode (BiPPGE) [ 136 ]; Direct-EI interface with LC-MS/MS in the fast determination of diazepam and flunitrazepam in alcoholic beverages [ 137 ]; determination of chlordiazepoxide and diazepam drugs using dispersive nanomaterial-ultrasound assisted microextraction followed by HPLC [ 138 ]; 2017 multivariate curve resolution - alternating least squares (MCR-ALS) analysis was used to quantify diazepam in thirty commercial liquid formulations reaching a relative error below of 1.66% against 2.56% [ 139 ]; rapid detection of Diazepam injection based on a droplet surface enhanced Raman spectroscopy (SERS) [ 140 ]; preferential solvation parameters of diazepam in binary solvent mixtures [ 141 ]; compatibility study between diazepam and tablet excipients investigated by thermal analysis (DSC and TG) and IR-spectroscopy [ 142 ]; Lab on paper chip integrated with silica coated gold nanorods (Si@GNRs) for electroanalysis of diazepam [ 143 ]; electrochemical determination of diazepam in real samples (commercial tablet, urine, and serum) based on fullerene-functionalized carbon nanotubes/ionic liquid nanocomposite [ 144 ]; FIA-based TELISA biosensing strategy to rapidly detect diazepam in beverages [ 145 ]; 2018 flow injection system for differential pulse amperometry (DPA) for diazepam determination [ 146 ]; UV/Vis spectrophotometric method was developed and validated for estimation of diazepam in tablet dosage form [ 147 ]; differential pulse adsorptive cathodic stripping voltammetry using a hanging mercury drop electrode was used for the determination of diazepam and clonazepam [ 148 ]; development of a glassy carbon electrode for the voltammetric detection of diazepam [ 149 ]; 2019 determination of chlorinated byproducts of diazepam using SPE-LC-EI-MS/MS [ 150 ].…”