Enzyme Biosensors For Detecting Carbamate Insecticides

Carbamate insecticides are widely employed in the agriculture due to their efficiency and relatively low persistence. Although pesticides can greatly increase the output of crops, residues of carbamate pesticides in the environment can lead to the accumulation of the neurotransmitter acetylcholine, which will cause respiratory and cardiac diseases. As a consequence, there are growing demands for rapid and sensitive measurements of carbamates.In this paper, two kinds of enzyme electrochemical biosensors were prepared based on the screen-printing technology. The physical properties of the electrodes, the immobilization and the inhibition of the enzyme were studied. These enzyme sensors could be applied for carbamate insecticides sensing. The composite nanomaterials prussian blue-multi-walled carbon nanotubes (PB-MWCNTs) and prussian blue-platinum (PB-Pt) were used to modify screen-printed electrodes (SPEs). And acetylcholinesterase (AChE) was trapped onto the electrode surface by adsorbing and crosslinking with glutaraldehyde. In order to obtain high sensitivity of the enzyme, several parameters related to the design of the biosensors were optimized, including temperature, electrolyte pH. enzyme amount, fixed time. These two sensors were further used to detect pesticides, and the inhibition rates of pirimicarb, chlorpyrifos and carbaryl were proportional to their concentration logarithms. In order to evaluate the performance of the detection system, the sensors were applied to determine pirimicarb, chlorpyrifos and carbaryl in water samples and exhibited high sensitivity and good stability. The recovery values of90to116%and RSD of2.1to5.6%were observed for Qingchun river water samples of East China University of Science and Technology, thus demonstrating low matrix effect on the signals of the biosensors.