Foi construído um eletrodo baseado em eletrodo de carbono vítreo modificado por um filme de nanotubos de carbono de paredes múltiplas ((MWCNTs)/poli(3-metil tiofeno, P3MT), que foi usado na determinação diferentes classes de pesticidas por voltametria de redissolução de onda quadrada. Inclui-se herbicidas (isoproturon), inseticidas (voltage, cipermetrina, deltametrina, fenvalerato), e acaricidas (dicofol). O comportamento eletroquímico dos pesticidas selecionados foi investigado na superfície do nanocomposito P3MT/MWCNT/GCE, em pH 1, 4, 7, 9,2 e 13. Os voltamogramas cíclicos do isoproturon (ISO) e voltage (VOL) exibiram picos de oxidação bem definidos em pH 1, enquanto os outros exibiram pico de redução em pH 13. A determinação por voltametria de redissolução de onda quadrada dos pesticidas acima citados foi desenvolvida no mesmo sistema modificado e baixos limites de detecção foram obtidos. O procedimento analítico proposto foi aplicado em águas naturais aditivadas com os pesticidas selecionados para validar o procedimento desenvolvido.A modified electrode fabricated by coating multiwalled carbon nanotubes (MWCNTs)/poly(3-methyl thiophene, P3MT) film on a glassy carbon electrode (GCE) and was used for the adsorptive stripping voltammetric determination of different classes of pesticides. These include herbicide (isoproturon), insecticides (voltage, cypermethrin, deltamethrin, fenvalerate) and an acaricide (dicofol). Electrochemical behaviour of all the selected pesticides was investigated on P3MT/ MWCNT/GCE nano composite surface at selected pHs 1, 4, 7, 9.2 and 13. In cyclic voltammetry, isoproturon (ISO) and voltage (VOL) exhibited one well-defined oxidation peak at pH 1, while remaining pesticides gave one reduction peak at pH 13. Adsorptive stripping voltammetric determination of above-said pesticides was developed on the same modified system and lowest detection limits were achieved. The proposed analytical procedure was applied to natural water samples spiked with the selected pesticides to validate the developed stripping procedure.Keywords: nano sensor, poly(3-methyl thiophene), herbicide, insecticide, acaricide IntroductionSince the discovery of carbon nanotubes (CNTs) in 1991, 1 they have been considered one of the most promising materials for various applications. In recent years, CNTs have been applied in various fields such as energy storage, 2 actuators, 3 and sensors. 4 Especially, it opens a new door for electroanalytical chemistry field because of its large specific surface area and good capability of electron transfer. It has been reported that CNTs modified electrodes were successfully applied to determine many biological and organic molecules such as ascorbic acid and uric acid, 5 NADH, 6 amino acids, 7 rutin, 8,9 hydrazine, 10 H 2 O 2 , 11 adenine, and guanine. 12,13 In recent years, conducting polymer/CNTs-modified electrodes have been of great interest in electrocatalysis reactions because of their unique chemical and electrochemical properties. It has also been demonstrated that the in...
A glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNT) and polymer/MWCNT composite was used to study the voltammetric behaviour of three common insecticides namely cypermethrin (CYP), deltamethrin (DEL) and fenvalerate (FEN). The modified electrode surface was characterised by scanning electron microscopy (SEM). The voltammograms of the above mentioned pollutants were studied in the pH range 1-13. Influence of scan rate () was also studied. One well-defined reduction peak was observed for all the said insecticides at pH 13. A systematic study of the experimental parameters such as accumulation potential, accumulation time, initial scan potential, amplitude and frequency that affect the square-wave stripping voltammetric response was carried out and maximum peak current conditions were optimised. Under optimum conditions, stripping voltammetric procedure was developed for the determination of above-mentioned insecticides in conventional and real samples. Calibration plots were derived and the lower limit of determination was found. Sensing of polypyrrole/MWCNT/GCE well among the three electrode systems and the limit of detection (LOD) was found to be 1.17, 3.8 and 1.62 mg L À1 for CYP, DEL and FEN, respectively. The percentage of relative standard deviation was also found.
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