Catalytic Chemosensing Assay for Selective Detection of Methyl Parathion Organophosphate Pesticide

Abstract

Herein, a catalytic chemosensing assay (CCA), based on a bimetallic complex, [RuII(bpy)2(CN)2]2(CuII)2 (bpy=2,2′‐bipyridine), is described. This complex integrates a task‐specific catalyst (CuI‐catalyst) and a signaling unit ([RuII(bpy)2(CN)2]) to specifically hydrolyze methyl parathion, a highly toxic organophosphate (OP) pesticide. The bimetallic complex catalyzed the hydrolysis of the phosphate ester to generate o,o‐dimethyl thiophosphate (DTP) anion and 4‐nitrophenolate. Intrinsically, 4‐nitrophenolate absorbed UV/Vis light at λmax=400 nm, creating the first level of the chemosensing signal. DTP interacted with the original complex to displace the chromophore, [RuII(bpy)2(CN)2], which was monitored by spectrofluorometry; this was classified as the second level of chemosensing signal. By integrating both spectroscopic and spectrofluorometric signals with a simple AND logic gate, only methyl parathion was able to provide a positive response. Other aromatic and aliphatic OP pesticides (diazinon, fenthion, meviphos, terbufos, and phosalone) and 4‐nitrophenyl acetate provided negative responses. Furthermore, owing to the metal‐catalyzed hydrolysis of methyl parathion, the CCA system led to the detoxification of the pesticide. The CCA system also demonstrated its catalytic chemosensing properties in the detection of methyl parathion in real samples, including tap water, river water, and underground water.

A Review of Nanocomposite-Modified Electrochemical Sensors for Water Quality Monitoring

“…Even lower LODs were found for methyl parathion (3.1 10 −7 μM), diazinon (6.7 10 −8 μM) and chlorpyrifos (3.3 10 −8 μM) in water samples using graphene oxide decorated with monodisperse boron nitride quantum dots [ 152 ]. Further examples can be found in [ 153 , 154 , 155 ].…”

Selective Detection of Methomyl Pesticide by a Catalytic Chemosensing Assay

“…In the design of CCA, the catalytic property of 1 is the key to its chemosensing selectivity to methomyl [14] . Figure 2 shows the spectrofluorometric titrations of the catalytic mixture including 1 (catalyst) and VC (reductant), with an increasing amount of methomyl.…”

“…In the design of CCA, the catalytic property of 1 is the key to its chemosensings electivity to methomyl. [14] Figure 2s hows the spectrofluorometric titrationso ft he catalytic mixture including 1 (catalyst) and VC (reductant), with an increasing amount of methomyl. On addition of methomyl to the catalytic mixture, not only was the CH 3 SH generated,b ut 1 was also found to have become dissociated into { .…”

The power of dissociation: development of displacement assays for chemosensing and latent catalytic systems

“…A novel Ru II -Cu I -based BmDAE, [Ru II (bpy) 2 (CN) 2 ] 2 -(Cu I I) 2 (19) comprised of two active catalytic units (Cu I -catalyst) and two signal transducer units (Ru II (bpy) 2 (CN) 2 ), was synthesized for the detection of methyl parathion, a highly toxic organophosphate pesticide via the CIDA. 33 Complex 19 was synthesized by stirring equimolar amounts of Cu I I and Ru(bpy)2(CN)2 in a methanol/acetonitrile mixture (1 : 10 v/v). The Cu I metallic receptor was employed because of its strong coordination to the phosphate ester group, 34 and its function as a luminescent quencher for the 3 MLCT of Ru II (bpy)(CN) 2 .…”