A New Indirect Electroanalytical Method to Monitor the Contamination of Natural Waters with 4-Nitrophenol Using Multiwall Carbon Nanotubes

Autor(es)

Moraes, Fernando Cruz ^[1] ; Tanimoto, Sonia Tomie ^[2] ; Salazar-Banda, Giancarlo Richard ^[2] ; Spinola Machado, Sergio Antonio ^[2] ; Mascaro, Lucia Helena ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Quim, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Electroanalysis; v. 21, n. 9, p. 1091-1098, MAY 2009.
• Citações Web of Science: 35

Resumo

The electrochemical detection of the hazardous pollutant 4-nitrophenol (4-NP) at low potentials, in order to avoid matrix interferences, is an important research challenge. This study describes the development, electrochemical characterization and utilization of a multiwall carbon nanotube (MWCNT) film electrode for the quantitative determination of 4-NP in natural water. Electrochemical impedence spectroscopy measurements showed that the modified surface exhibits a decrease of ca. 13 times in the charge transfer resistance when compared with a bare glassy carbon (GC) surface. Voltammetric experiments showed the possibility to oxidize a hydroxylamine layer (produced by the electrochemical reduction of 4-NP on the GC/MWNCT surface) in a potential region which is approximately 700 mV less positive than that needed to oxidize 4-NP, thus minimizing the interference of matrix components. The limit of detection for 4-NP obtained using square-wave voltammetry (0.12 mu mol L(-1)) was lower than the value advised by EPA. A natural water sample from a dam located in Sao Carlos (Brazil) was spiked with 4-NP and analyzed by the standard addition method using thee GC/MWCNT electrode, without any further purification step. the recovery procedure yielded a value of 96.5% for such sample, thus confirming the suitability of the developed method to determine 4-NP in natural water samples. The electrochemical determination was compared with that obtained by HPLC with UV-vis detection. (AU)

• Processo FAPESP: 06/50692-2 - O uso do metodo sol-gel para a producao de recobrimentos de sio2 e/ou ceo2 sobre ligas de aluminio utilizadas na industria aeronautica para a protecao contra a corrosao.
• Beneficiário: Giancarlo Richard Salazar Banda
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado