Voltammetric determination of chlorothalonil and its respective reduction mechanism studied by density functional theory

Autor(es)

Lima, Thays Souza ^[1] ; La-Scalea, Mauro A. ^[1] ; Raminelli, Cristiano ^[1] ; Simoes, Fabio R. ^[2] ; Franco, Jr., Edison ^[3] ; da Silva, Gabriela Dias ^[3] ; Salvador, Michele Aparecida ^[3] ; Homem-de-Mello, Paula ^[3] ; de Oliveira, Hueder P. M. ^[3] ; Codognoto, Lucia ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Paulo UNIFESP, Inst Ciencias Ambientais Quim & Farmaceut, Dept Quim, Rua Prof Artur Riedel, 275 Bairro Eldorado, BR-09972270 Diadema, SP - Brazil

^[2] UNIFESP, Dept Ciencias Mar, Santos, SP - Brazil

^[3] Univ Fed ABC UFABC, Santo Andre, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Solid State Electrochemistry; v. 23, n. 2, p. 553-563, FEB 2019.
• Citações Web of Science: 0

Resumo

A simple, fast, and direct electroanalytical method has been developed for the pesticide chlorothalonil determination using a boron-doped diamond electrode and square-wave voltammetry technique. In the pH range values between 8.0 and 10.0, the voltammetric results showed three reduction peaks -1.07, -1.2, and -1.4V (vs. Ag/AgCl) for the chlorothalonil. This reduction mechanism is based on three consecutive dehalogenation steps proposed by density functional theory and the calculation of the Chelpg charge values. The results showed that the most negatively charged carbon was the first dehalogenated and the following dehalogenations for the intermediates occurred by the chloride anions loss from their most respective negative carbon atoms. From the square wave voltammetric behavior of chlorothalonil, an analytical method was developed in which the calibration curve was obtained in a concentration range of 1.2x10(-7) to 4.0x10(-6)molL(-1) with sensitivity of 0.29 A/molL(-1) and linear correlation coefficient of 0.997. The limits of detection (LOD) and quantification (LOQ) were 4.0x10(-8)molL(-1) (10.6gL(-1)) and 1.2x10(-7)molL(-1) (55.8gL(-1)), respectively, being lower than the maximum values allowed by the Environmental Protection Agency and the Brazilian National Surveillance Agency. Tea infusion samples (lemon grass, spearmint, strawberry, and orchard) were spiked with the chlorothalonil pesticide standard solutions. The results showed recovery values between 98.0 and 103.0% for 1.0x10(-6)molL(-1)concentration, indicating the applicability of this method for different complex matrices. (AU)

• Processo FAPESP: 17/24742-7 - Sensores baseados em compósitos de polímeros condutores e grafeno visando à determinação de substâncias desreguladoras endócrinas em ambiente marinho
• Beneficiário: Fabio Ruiz Simões
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 08/50588-6 - Eletrodos de ouro modificados por monocamadas auto-organizadas aplicados à determinação de pesticidas
• Beneficiário: Lucia Codognoto de Oliveira
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