Voltammetric Detection of Nitrite Throught a Chemically Modified (5-Amino-1,3,4-Thiadiazolyl-2-Thiol) Propyl Silica Gel

This study describes an organofunctionalization of 3-chloropropyl silica gel (SG) with 5-amino-1,3,4-thiadiazolyl-2-thiol, and was characterized by spectroscopic techniques as infrared spectroscopy and nuclear magnetic resonance spectroscopy. After characterized, copper ions (Cu2+) were adsorbed and subsequent reaction of potassium hexacyanoferrate (CuSATTH), a systematic study was performed around the voltammetric behavior of the material. The cyclic voltammogram of graphite paste electrode modified with CuSATTH showed two well-defined redox pairs with formal potentials of 0.12 V (I) and 0.83 V (Ag/AgCl(sat.)) assigned Cu(I)/Cu(II) and Fe(II)(CN)5NO/Fe(III)(CN)5NO, respectively (80% w/w; v = 20 mV s−1; NH4NO3 1.0 mol L−1). It was for observed for CuSATTH, using graphite paste electrode, an sensitivity to different concentrations of nitrite. The analytical curve constructed shows a linear response of 6.0 × 10−6 to 9.0 × 10−5 mol L−1 (R = 0.998), 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.