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A composite prepared from titanium (IV) silsesquioxane and phosphoric acid (TTiP) was prepared and occluded into the H-FAU zeolite (ZTTiP). The material was chemically modified with nickel and subsequently by potassium hexacyanoferrate (III) (ZTTiPNiH). It was preliminarily characterized by infrared spectroscopy (IR), energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry (CV). The voltammetric behavior of ZTTipNiH was obtained employing a modified graphite paste electrode (GPE) showing one well-defined redox couple with a formal potential of E θ = 0.51V (vs Ag/AgCl(sat)), KCl (3M) (20% w/w; v = 20 mV s −1 ; KCl; 1.00 mol L −1 ) corresponding to the Ni II Fe II (CN) 6 /Ni II Fe III (CN) 6 redox process. After rigorous voltammetric studies, the GPE modified with ZTTiPNiH was applied for facile and rapid detection of sulfite. From the analytical curve, a linear response was obtained in a concentration range of 0.05 to 0.80 mmol L −1 and a detection limit (3σ ) of 0.05 mmol L −1 with a relative standard deviation of 4.21% (n = 3) and an amperometric sensitivity of 14.42 mA L mol −1 for sulfite. KeywordsSilsesquioxanes • Titanium (IV) silsesquioxane • Zeolite • Nickel hexacyanoferrate (III) • Voltammetry • Sulfite

This work describes the organofunctionalization and a complementary characterization and application of an octakis(3-chloropropyl)octasilsesquioxane (1) with 4-Amino-5-Phenyl-4H-[1,2,4]-Triazole-3-Thiol (2). The functionalized silsesquioxane (3) was characterized by nuclear magnetic resonance, X-ray diffraction, transmission electron microscopy and thermogravimetric analysis. After functionalized, the silsesquioxane can interact with copper chloride and subsequently with potassium hexacyanoferrate (III) (4). The hybrid composite formed (4) was characterized by FT-IR and diffuse reflectance. The compound 4 included into a work graphite paste electrode (20% w/w) was examined for chronoamperometric determination of L-Dopamine. The modified graphite paste electrode with compound 4 showed a linear response from 2.5×10 −5 at 4.0×10 −4 mol L −1 . The modified graphite paste electrode with 4 showed a detection limit of 2.08× 10 −4 mol L −1 with a relative standard deviation of ±2% (n = 3) and amperometric sensitivity of 0.136 A mol L −1 .

The present work reports the voltammetric behavior of Zinc hexacyanoferrate (III) nanoparticles and their application in the detection of N-acetylcysteine. Two distinct ratios of water/formamide 10:0 (ZnH-1) and 4:6 (ZnH-2) were studied in the complexation reaction of Zn

In this work, the 3‐chloropropyl silica gel (SG) was prepared and organofunctionalized with 4‐amino‐5‐(4pyridyl)‐4H‐1,2,4‐triazole‐3‐thiol (SGA), that was characterized by infrared spectroscopy (FTIR) and cyclic voltammetry (CV). The cupric ions (Cu2+) sorption on the silica functionalized surface (CuSGA) were performed in aqueous solution, at room temperature. It was performed a systematic study about voltammetric behavior of CuSGA, where the cyclic voltammogram of graphite paste electrode modified with CuSGA exhibited a single redox pair with formal potential (Eθ′)=0.30 V assigned to the process Cu+/Cu2+, (KCl 1.0 mol L−1, v=20 mV s−1). The graphite paste electrode modified with CuSGA was sensitive to different concentrations of ascorbic acid and then an analytical curve could be constructed, with a linear response of 6.0×10−6 to 9.0×10−5 mol L−1 (R=0.9988) and a relative standard deviation of ±2.5 % (n=3). The detection limit (3σ) and amperometric sensitivity were 4.78×10−6 mol L−1 and 115.96 mA/mol L−1, respectively.

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This work describes the preparation of graphene oxide by the Modified Hummers Method and the chemical modification of its surface with nanoparticles of copper pentacyanonitrosylferrate(III) (GOCuNP). The materials obtained were characterized by Raman spectroscopy, x‐ray photoelectron spectroscopy and transmission electron microscopy. The GOCuNP was characterized by cyclic voltammetry using a graphite paste electrode that presented electrocatalytic response for N‐acetylcysteine with detection limit of 2.97×10−5 mol L−1 at concentration range of 3.00×10−5 to 6.00×10−3 mol L−1 of N‐acetylcysteine. By this way, the bimetallic complex formed is included in the list of materials obtained as potential candidates for the construction of electrochemical sensors for N‐acetylcysteine detection.

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