A Sensitive Electrochemical Aptasensor Based on Black Phosphorus Nanosheet for Carbaryl Detection

Abstract

Carbaryl is a broad-spectrum carbamate insecticide widely used to control pests on crops, trees and ornamental plants. Carbaryl residues in fruits and vegetables and other foods can accumulate in the human body and damage human health. Therefore, it is very essential to establish a sensitive and reliable method for determination of carbaryl. Black phosphorene nanosheets (BPNPs) modified glassy carbon electrode was herein prepared using poly(3,4-dioxyethylenethiophene)-poly(styrene sulfonate) (PEDOT: PSS) as both membrane and stabilizer. The nanocomposites (BP-PEDOT: PSS) were synthesized by combining BP at the ratio of PEDOT: PSS, which improved conductivity and stability of BP. In order to enhance the electrochemical signal and build the carbaryl aptamer sensor, the surface of BP-PEDOT: PSS was modified by Au nanoparticles (Au NPs). The carbaryl aptamer modified with sulfhydryl groups was immobilized in the outer layer of Au NPs, and the target carbaryl was specifically recognized and captured by carbaryl aptamer and adsorbed on the electrode surface, thus causing changes in the interfacial electrochemical signal. The conditions were optimized and characterized by cyclic voltammetry (CV), and linear equation was obtained as ΔI(μA) = −11.35logC−29.70, R2 = 0.997. The detection range was 0.01 ng/mL–10 μg/mL, with a limit of detection of 7.0 pg/mL.