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Electrochemical Sensor for Hydrazine Based on Silica Modified with Nickel Tetrasulfonated Phthalocyanine
Author(s) -
Perez Elizabeth F.,
Neto Graciliano de Oliveira,
Tanaka Auro A.,
Kubota Lauro T.
Publication year - 1998
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199802)10:2<111::aid-elan111>3.0.co;2-v
Subject(s) - nickel , phthalocyanine , hydrazine (antidepressant) , oxidizing agent , redox , inorganic chemistry , electrochemistry , chemistry , electrocatalyst , detection limit , electrode , carbon paste electrode , cyclic voltammetry , electron transfer , analytical chemistry (journal) , organic chemistry , chromatography
Nickel tetrasulfonated phthalocyanine (NiTsPc) immobilized onto titanized silica gel (ST) showed good stability and redox properties. The cyclic voltammograms obtained with a carbon paste electrode modified with ST‐NiTsPc presented an enhanced peak current at 450 mV (vs. SCE) which did not shift with solution pH. The redox process was attributed to Ni II /Ni III , which presented a good electrocatalytical activity for oxidizing hydrazine in neutral solution. The process is controlled by the electron transfer step and no diffusion limitation was observed. The modified electrode was very sensitive for hydrazine, giving a detection limit of 1.0 × 10 −5 mol L −1 , for an applied potential of 450 mV (vs. SCE). A linear response range was observed between 1.0 × 10 −4 and 6.0 × 10 −4 mol L −1 , fit by the equation I = −0.1 (± 0.1) + 7.9 (± 0.3) [Hydrazine], with a correlation coefficient of 0.998 for n = 6. The repeatability for 11 measurements was excellent, with a relative standard deviation of 3.7 %. The active material, nickel tetrasulfonated phthalocyanine modified silica, was stable for at least 6 months, losing only 10 % of its signal over this period.