title: Inhibition-based first-generation electrochemical biosensors: theoretical aspects and application to 2,4-dichlorophenoxy acetic acid detection.
abstract: In this work, several theoretical aspects involved in the first-generation inhibition-based electrochemical biosensor measurements have been discussed. In particular, we have developed a theoretical-methodological approach for the characterization of the kinetic interaction between alkaline phosphatase (AlP) and 2,4-dichlorophenoxy acetic acid (2,4-D) as representative inhibitor studied by means of cyclic voltammetry and amperometry. Based on these findings, a biosensor for the fast, simple, and inexpensive determination of 2,4-D has been developed. The enzyme has been immobilized on screen-printed electrodes (SPEs). To optimize the biosensor performances, several carbon-based SPEs, namely graphite (G), graphene (GP), and multiwalled carbon nanotubes (MWCNTs), have been evaluated. AlP was immobilized on the electrode surface by means of polyvinyl alcohol with styryl-pyridinium groups (PVA-SbQ) as cross-linking agent. In the presence of ascorbate 2-phosphate (A2P) as substrate, the herbicide has been determined, thanks to its inhibition activity towards the enzyme catalyzing the oxidation of A2P to ascorbic acid (AA). Under optimum experimental conditions, the best performance in terms of catalytic efficiency has been demonstrated by MWCNTs SPE-based biosensor. The inhibition biosensor shows a linearity range towards 2,4-D within 2.1-110 ppb, a LOD of 1 ppb, and acceptable repeatability and stability. This analysis method was applied to fortified lake water samples with recoveries above 90%. The low cost of this device and its good analytical performances suggest its application for the screening and monitoring of 2,4-D in real matrices.
authors.affiliation: Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bollella
authors.affiliation: Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.|Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Fusco
authors.affiliation: Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.|Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Tortolini
authors.affiliation: Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Sanzò
authors.affiliation: Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.
authors.forename: Riccarda
authors.initials: R
authors.lastname: Antiochia
authors.affiliation: Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Favero
authors.affiliation: Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy. franco.mazzei@uniroma1.it.
authors.forename: Franco
authors.initials: F
authors.lastname: Mazzei
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis*; D015374:Biosensing Techniques; D055664:Electrochemical Techniques / Q000379:methods*; D007700:Kinetics
chemical_list: D015084:2,4-Dichlorophenoxyacetic Acid
keywords: 2,4-D; Inhibition biosensor; Phosphatase alkaline; Screen printed electrode