Rapid Determination of Organic Phosphorus Pesticide Residue by a Carbon Nanotube/Acetylcholinesterase Electrochemical Biosensor
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Organic phosphorus is a type of neurotoxin capable of inhibiting the activity of acetylcholinesterase (AChE) in the blood and tissues. During AChE catalysis, acetylthiolcholine chloride (ATCl) was hydrolyzed to thiol choline (TCl) in aqueous solution, and TCl was oxidized on the surface of the electrode, thus enabling the detection of large current signals. However, both AChE activity and TCl electrochemical signals produced by hydrolysis decreased in the presence of organic phosphorus. Based on this principle, a new biosensor for the quantitative determination of organic phosphorus was constructed by immobilizing functionalized multi-wall carbon nanotubes (FMWCNTs), p-DSPAB, and AChE on the surface of carbon-paste electrodes. The content of MWCNTs was 1.0 μg/cm2 and the AChE load on the modified electrode was 1.5 U. Under optimal conditions, the measurement of organic phosphorus by differential-pulse voltammetry was performed in 5.0 mL of 50 mmol/L PBS (pH 7.0) solution using 3.0 ng/mL ATCl as the substrate. The detection parameters were as follows: pulse increment, 0.006 V; pulse amplitude, 0.05 V; pulse width, 0.1 V; and pulse interval, 0.1 s. According to the change in the response current and the concentration of organic phosphorus, the biosensor offered a linear range of ~3.00–90.00 ng/mL for the detection of organic phosphorus, and the detection limit was 1.00 ng/mL (S/N = 3). Compared with HPLC, this method has the advantages of simplicity, rapidity, sensitivity, and accuracy in the determination of organic phosphorus.
