Voltammetric determination of nitrite by using a glassy carbon electrode modified with a self-assembled nanocomposite prepared from CdTe quantum dots, cetyltrimethylammonium bromide, chitosan and multiwalled carbon nanotubes

The authors describe an electrostatic self-assembly strategy for the modification of a glassy carbon electrode (GCE) with CdTe quantum dots (QDs), cetyltrimethylammonium bromide, chitosan, and multiwalled carbon nanotubes (MWCNTs). The nanocomposite was characterized by scanning electron microscopy revealing the distribution of spherically shaped CdTe QDs on the tubular networks of the MWCNTs. The modified GCE is shown to enable improved voltammetric sensing of nitrite, best at a working potential of 0.78 V (vs. SCE). The synergetic effect of the four components leads to rapid electron transfer and in an increased active area. Hence, excellent electrocatalytic activity towards the oxidation of nitrite is observed. Square wave voltammetry was applied to quantify nitrite, and the two linear ranges cover the 1 to 100 μmol L −1 and 100 to 600 μmol L −1 nitrite concentration ranges. The detection limit is 0.30 μmol L −1 . The method was applied to the determination of nitrite in pickled vegetables and the results were compared to a UV-Vis method. The method is found to be sensitive, accurate, rapid, and well repeatable. Schematic illustration of the procedure of the modification of a glassy carbon electrode (GCE) with CdTe quantum dots (QDs), cetyltrimethylammonium bromide (CTAB); chitosan (Chit) and multiwalled carbon nanotubes (MWCNTs).