Rapid extraction and quantitative detection of the herbicide diuron in surface water by a hapten-functionalized carbon nanotubes based electrochemical analyzer

Abstract

A solid phase extraction micro-cartridge containing a non-polar polystyrene absorbent matrix was coupled with an electrochemical immunoassay analyzer (EIA) and used for the ultra-sensitive detection of the phenyl urea herbicide diuron in real samples. The EIA was fabricated by using carboxylated carbon nanotubes (CNTs) functionalized with a hapten molecule (an amine functionalized diuron derivative). Screen printed electrodes (SPE) were modified with these haptenized CNTs and specific in-house generated anti diuron antibodies were used for bio-interface development. The immunodetection was realized in a competitive electrochemical immunoassay format using alkaline phosphatase labeled secondary anti-IgG antibody. The addition of 1-naphthyl phosphate substrate resulted in the production of an electrochemically active product, 1-naphthol, which was monitored by using differential pulse voltammetry (DPV). The assay exhibited excellent sensitivity and specificity having a dynamic response range of 0.01 pg mL(-1) to 10 μg mL(-1) for diuron with a limit of detection of around 0.1 pg mL(-1) (n = 3) in standard water samples. The micro-cartridge coupled hapten-CNTs modified SPE provided an effective and efficient electrochemical immunoassay for the real-time monitoring of pesticides samples with a very high degree of sensitivity.

Sensitive Carbon Fiber Microelectrode for the Quantification of Diuron in Quality Control of a Commercialized Formulation

“…Despite the fact that the tested p-NiTSPc-CFME is a microelectrode, it exhibited comparable sensor performances with some macroelectrodes reported in the literature. As seen in Table 1, the obtained detection limit (8.030 μM) was lower and even better [24] than that previously reported. us, the obtained results may be considered as a good starting point of reference for the electroanalysis of diuron using for the first time a carbon fiber microsensor.…”

Probing the surface of oxidized carbon nanotubes by selective interaction with target molecules

“…The weight loss provides an estimate of the functionalization degree as it results from the loss of chemical groups/molecules bonded to the CNT walls. Different functional groups can be introduced by oxidation such as: hydroxyl-phenolic, carbonyl-quinone, carboxyl and lactone [6,[14][15][16]. The fact that the different weight vs. temperature curves of CNT ox display similar shapes hints that the nature of the functionalization introduced by oxidation is similar despite the treatment duration.…”

High-performance electrochemical amperometric sensors for the sensitive determination of phenyl urea herbicides diuron and fenuron

“…It has been also extensively used in non-crop fields, such as drainage ditches, irrigation waterways, garden areas, road sides, and railway lines to control growth of weeds [2]. Moreover, DU is also employed in water bodies, home aquaria, fountains, boats, and aquaculture to control algae (algaecide) [2,3]. It blocks the light reaction of photosystem II by selective reversible binding at the quinone binding site which results in complete hindrance of electron transfer from quinone to plastoquinone; as a consequence, photosynthesis was inhibited [4,5].…”

“…These residues can cause severe health effects in both human beings and animals upon its absorption [2,6]. According to the European Union Directive, the allowed amount of DU in ground water is 0.1 ng/mL [3]. DU exposure to human is resulting in the formation of methemoglobin in blood and liver, and it also affects the disposal of natural hormones in the body.…”