A New Chemosensor Based on a Luminescent Complex for the Investigation of Some Organophosphorus Pesticides in Environmental Samples

Abstract

Organophosphorus pesticides (OPPs) play a vital role in agriculture. However, their release into the environment can have serious repercussions. Therefore, the development of rapid and reliable methods for determining OPPs has received considerable attention in recent decades. Here, a new chemosensor based on a complex of vitamin B1 (vitB1) as a ligand with europium(III) ion, with a 1:2 stoichiometric ratio, was developed in solution to detect chlorfenvinphos and malathion in water samples using the luminescence method. The detection method is based on the luminescence quenching of a Eu(III)–vitamin B1 probe in solution upon increasing the concentration of chlorfenvinphos or malathion. The optimum solvent for the detection was methanol. The detection limits were 0.31 and 0.12 µM for chlorfenvinphos and malathion, respectively. According to the ratiometric method, malathion has a 13-fold higher binding affinity for the Eu(III)–(vitB1)2 complex than chlorfenvinphos. The reaction between the probe and OPPs under study was spontaneous and had a negative ΔG0. The method was successfully applied to determine chlorfenvinphos and malathion in three different water samples. Based on these studies, future work will be carried out to establish the optic fiber sensor.