Characterization of recognition sites for diethyl 4-nitrobenzylphosphonate, an organophosphate pesticide analogue

• Published in: Analytica chimica acta Vol. 614; no. 1; pp. 63 - 70
• Main Authors: Gué, Anne-Marie, Lattes, Armand, Laurent, Elisabeth, Mauzac, Monique, Mingotaud, Anne-Françoise
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 28.04.2008; Elsevier
• Subjects: Analytical chemistry; Benzyl Compounds - analysis; Chemical and thermal methods; Chemistry; Exact sciences and technology; General, instrumentation; Isothermal titration calorimetry; Magnetic Resonance Spectroscopy; Molecular imprinted polymers; Organophosphorus Compounds - analysis; Pesticides; Pesticides - analysis; Sensors; Spectrometric and optical methods; Spectrophotometry, Infrared; Isothermal titration calorimetry; Sensors; Molecular imprinted polymers; Pesticides; Stoichiometry; Molecular structure; Association constant; Polymer; Organic phosphonate; NMR spectrometry; Chemical sensor; Infrared spectrometry; Calorimetry; Titration
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2008.03.016

In a first step towards chemical sensors using molecular imprinted materials, the complexing characteristics of diethyl 4-nitrobenzylphosphonate, an organophosphate pesticide analogue, have been studied. Two molecules have been assessed as potential interacting moieties, specifically a fluoroalcohol and an aromatic acid. The interactions have been first characterized by regular methods, such as 1H, 31P NMR and IR spectroscopy. These showed a stoichiometry 1/1 for both complexes and association constants, respectively, close to 40 ± 10 and 12 ± 2 M −1. In a second step, isothermal titration calorimetry was used and a method was developed to obtain low-association constants. The association constant could be obtained for the fluoroalcohol ligand and was found equal to 63 ± 0.7 M −1. For the acidic molecule, an appropriate model could not be found, preventing the evaluation of this constant.