Graphenated electrode protocol for electrochemical nanosensing of 17β- estradiol as an environmental estrogeneous endocrine disruptor

Philosophiae Doctor - PhD (Chemistry)17β-Estradiol can be defined as an endocrine disruptor chemical with estrogenic activity, which can bind to the estrogen receptor in the body and potentially alter the normal physiological function of the endocrine systems. Estradiol has come into veterinary use both to cure and to prevent animal infections. But owing to its anabolic properties it is also illegally used in livestock production for growth promotion purposes. The presence of low concentrations of estrogens in the environment can cause abnormal sexual development of animals and decrease the average number of human spermatozoa. Therefore, we must monitor the concentration of estradiol in aquatic environment to protect the health of humans and animals. Generally, the detection of estradiol includes the use of high performance liquid chromatography (HPLC), surface plasma resonance (SPR), gas chromatography (GC), liquid chromatography (LC) and electrochemical enzymelinked immunosorbent assay (ELISA). Although these techniques are useful, many of them are expensive and time consuming

Electrochemical studies of monosubstituted squarate ligands and its transition metal and lanthanide complexes

Magister Scientiae - MScThe study introduces and puts forward Sector Policing as a model to expand community Policing and to broaden the scope of crime prevention. It also demonstrates how Sector Policing can be utilised to decentralise policing and deepen community participation.South Afric

Electrochemically reduced graphene oxide pencil-graphite in situ plated bismuth-film electrode for the determination of trace metals by anodic stripping voltammetry

An electrochemical platform was developed based on a pencil-graphite electrode (PGE) modified with electrochemically reduced graphene oxide (ERGO) sheets and in conjunction with an in situ plated bismuth-film (ERGO-PG-BiE). The ERGO-PG-BiE was used as a sensing platform for determining Zn2+, Cd2+ and Pb2+ by square wave anodic stripping voltammetry (SWASV). ERGO sheets were deposited on to pencil-graphite electrodes by cyclic voltammetric reduction from a graphene oxide (GO) solution. The GO, with flake thicknesses varying between 1.78 to 2.10 nm (2 sheets) was characterized using FT-IR, HR-SEM, HR-TEM, AFM, XRD and Raman spectroscopy. Parameters influencing the electroanalytical response of the ERGO-PG-BiE such as, bismuth-film concentration, deposition potential, deposition time and rotation speed were investigated and optimized. The ERGO-PG-BiE gave well-defined, reproducible peaks with detection limits of 0.19 μg L-1, 0.09 μg L-1 and 0.12 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively, at a deposition time of 120 seconds. For real sample analysis, the enhanced voltammetric sensor proved to be suitable for the detection and quantitation of heavy metals below the US EPA prescribed drinking water standards of 5 mg L-1, 5 μg L-1 and 15 μg L-1 for Zn2+, Cd2+ and Pb2+ respectively