A novel amperometric immunosensor based on {MWCNTs-COOH-CHIT}2/GNPs for detection of chlorpyrifos

作者：Sun Xia^*; Qiao Lu; Wang Xiangyou

来源：Sensors and Transducers, 2012, 146(11): 96-109.

• Amperometric immunosensors
• Chlorpyrifos
• Detection limits
• Detection sensitivity
• Dual layer
• Electroactive species
• Electrode surfaces
• Fruits and vegetables
• Glassy carbon electrodes
• Gold Nanoparticles
• High reproducibility
• Homogeneous solutions
• Immobilization effects
• Label free
• MWCNTs-COOH-CHIT
• Negatively charged
• Optimal experimental conditions
• Poly(diallyldimethylammonium chloride)
• Positively charged
• Regeneration performance
• Stepwise assembly
• Wide-linear range

In this study, a novel label-free amperometric immunosensor based on gold nanoparticles and dual-layer carboxylated multiwall carbon nanotubes-chitosan ({MWCNTs-COOH-CHIT}2/GNPs) for the determination of chlorpyrifos residues was exploited. To construct the immunosensor, MWCNTs-COOH was first dispersed with CHIT to obtain a homogeneous solution and then it was dropped on the surface of glassy carbon electrode (GCE) which was first modified by the electrodeposition of GNPs. And then the modified GCE was immersed in the poly (diallyldimethylammonium chloride) (PDDA) which was positively charged. Next, the negatively charged MWCNTs-COOH-CHIT was assembled to the interface through the electrostatic force. The stepwise assembly process of electroactive species on electrode surface and the performance of the immunosensor was characterized by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM), respectively. {MWCNTs-COOH-CHIT}2 was acted as an electron promoter and had excellent immobilization effects for antibody, thus, it improved the detection sensitivity and stability of the immunosensor. Under optimal experimental conditions, the proposed immunosensor had a wide linear range from 0.1 to 50 ng/mL and from 50ng/mL to 1mg/mL, and with a detection limit of 0.069 ng/mL. The proposed immunosensor exhibited high reproducibility, specificity, stability and regeneration performance, which provided a new promising tool for the detection of chlorpyrifos residues in fruits and vegetables.

• 出版日期2012
• 单位山东大学