Trends in Flow-based Biosensing Systems for Pesticide Assessment

Abstract

This review gives a survey on the state of the art of pesticide detection using flow-based biosensing systems for sample screening. Although immunosensor systems have been proposed as powerful pesticide monitoring tools, this review is mainly focused on enzyme-based biosensors, as they are the most commonly employed when using a flow system. Among the different detection methods able to be integrated into flow-injection analysis (FIA) systems, the electrochemical ones will be treated in more detail, due to their high sensitivity, simple sample pretreatment, easy operational procedures and real-time detection. During the last decade, new trends have been emerging in order to increase the enzyme stability, the sensitivity and selectivity of the measurements, and to lower the detection limits. These approaches are based on (i) the design of novel matrices for enzyme immobilisation, (ii) new manifold configurations of the FIA system, sometimes including miniaturisation or lab-on-chip protocols thanks to micromachining technology, (iii) the use of cholinesterase enzymes either from various commercial sources or genetically modified with the aim of being more sensitive, (iv) the incorporation of other highly specific enzymes, such as organophosphate hydrolase (OPH) or parathion hydrolase (PH) and (v) the combination of different electrochemical methods of detection. This article discusses these novel strategies and their advantages and limitations.

Inhibition of AChE by malathion and some structurally similar compounds

“…However, while the time of analysis required for one determination of enzyme activity is about 2 min, the sensitivity is not very high and sometimes does not satisfy EU Framework Directive requirements [14,28]. Although most flow-through enzyme sensors for pesticide analysis are electrochemical [29], a new detection method (thermal lens spectrometry) was recently applied in combination with a cholinesterase biosensor and showed low limits of detection [15 -17].…”

Electrochemical Biosensors for Determination of Organophosphorus Compounds: Review

“…Organophosphorus hydrolase (OPH) has broad substrate specificity and is able to hydrolyze a number of OP pesticides such as paraoxon, parathion, coumaphos, diazinon, dursban, methyl parathion [13]. The hydrolysis involves a pH change, as well as electroactive species generation, thus allowing the development of potentiometric and amperometric sensors for OP pesticides quantification [59][60][61][62][63][64][65]. The change in pH was measured using a pH electrode and there were drawbacks of sensitivity, calibration.…”

Developments in Analytical Methods for Detection of Pesticides in Environmental Samples

“…In spite of their clear advantages, they have certain limitations. They have low response stability low mechanical stability, high diffusion resistance of substrate/bio component assembly; interfering signals form other compounds in real samples etc [51]. However, these drawbacks can be minimized by proper designing of the biosensor.…”