Construction of a chemically modified electrode for the selective determination of nitrite and nitrate ions based on a new nanocomposite

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• 作者：Abbas Afkhami^a ; ^{afkhami@basu.ac.ir} ; Tayyebeh Madrakian^a ; Hamed Ghaedi^a ; Hamid Khanmohammadi^b
• 关键词：Nitrite and nitrate determination ; Chemically modified electrode ; Square wave anodic voltammetry ; Azo-linked pyridazine-based Schiff base
• 刊名：Electrochimica Acta
• 出版年：2012
• 期刊代码：30_00134686
• 类别：ch
• 出版时间：1 April, 2012
• 卷：66
• 期：Complete
• 页码：255-264
• 文件大小：1130 K

摘要

A new chemically modified electrode was constructed for rapid, simple, accurate, selective and highly sensitive determination of nitrite and nitrate in mixture using square wave stripping voltammetry (SWASV). The electrode was prepared by incorporation of synthesized nanocomposite 3,6-bis(2-[2-sulfanyl-ethylimino-methyl]-4-(4-nitro-phenylazo)-phenol)pyridazine coated SiO₂@Fe₃O₄ (L-SCMNPs) in carbon paste electrode. The prepared nanocomposite was characterized by SEM, XRD and FTIR measurements. Nitrite ion was oxidized at the surface of the modified electrode at 0.970 V vs. Ag/AgCl. Nitrate was first reduced to nitrite and accumulated at the electrode surface by applying the accumulation potential of 鈭?.300 V and then oxidized at 0.970 V vs. Ag/AgCl. The limit of detection was found to be 0.034 mg L^鈭? (0.625 渭mol L^鈭?) and 5.4 mg L^鈭? (87 渭mol L^鈭?) for NO₂^-and NO₃^-, respectively. The effects of different cations and anions on the determination of NO₂^-and NO₃^-, in the presence of each other, were investigated and found that the electrode is highly selective. The proposed chemically modified electrode was used to the determination of NO₂^-and NO₃^-in several foodstuffs and water samples.