ABSTRACT
Paraquat is one of the most toxic materials widely applied in agriculture in most countries. In the present study, a simple, innovative and inexpensive nano biosensor which is based on a thioglycolic acid (TGA) - CdTe@CdS core-shell nanocrystals (NCs) to detect paraquat, is suggested. The NCs based biosensor shows a linear working range of 10-100 nM, and limited detection of 3.5 nM. The proposed sensor that has been well used for the detection and determination of paraquat in natural water samples is collected from corn field and a canal located near to the corn field yielding recoveries as high as 98%. According to our findings, the developed biosensor shows reproducibility and high sensitivity to determine paraquat in natural water samples in which the amount of paraquat has low levels. The suggested method is efficiently applied to paraquat determination in the samples of natural water that are collected from a tap water and a canal located near to the cornfield.
Subject(s)
Fluorescent Dyes/chemistry , Nanoparticles/chemistry , Paraquat/analysis , Water Pollutants, Chemical/analysis , Biosensing Techniques , Cadmium Compounds/chemistry , Hydrogen-Ion Concentration , Sulfates/chemistry , Tellurium/chemistry , Thioglycolates/chemistryABSTRACT
In the present research, 4,4'-biphenol was used as a homogeneous mediator for determining cysteine (CySH) on a Glassy Carbon Electrode (GCE). To describe the electrochemical properties of 4,4'-biphenol and to examine its electrocatalytic impacts on cysteine oxidation, both Cyclic Voltammetry (CV) and Linear Sweep Voltammetry (LSV) were employed. Our findings revealed that 4,4'-biphenol could significantly accelerate the reactions related to electron transfer to CySH. Moreover, the diffusion coefficient of CySH and its reaction with the catalytic constant of 4,4'-diphenoquinone was estimated via chronoamperometry technique. The results showed that cysteine concentration range of 10-1000 µM led to linear increases in the oxidation peaks, thus to providing a detection of 0.99 µM with R² = 0.993. A Relative Standard Deviation (RSD) of 2.5% was achieved after performing 7 cysteine replicates (100 µM), and CySH was successfully determined in real serum samples through the proposed approach.
