Abstract
A simple, rapid method of the determination of nitrite in food samples is reported by using a highly sensitive electrochemical sensor based on nickel, poly(diallyldimethylammonium chloride) (PDDA), reduced graphene oxide (rGO) and a disposable screen-printed carbon electrode (SPCE). The method is based on a modification of the electrode to enhance the sensitivity and selectivity of the disposable and applicable SPCE, which is essential for the present analytical challenge. The nitrite determination was performed by using a cyclic voltammetry (CV) method under optimum conditions. Ni/PDDA/rGO/SPCE showed a linear working range of 6 to 100 μM of nitrite concentration. The limit of detection and limit of quantification were 1.99 μM (S/N = 3) and 6.6 μM (S/N = 10), respectively. The sensitivities were 0.453 μA μM-1 cm-2 for the lower concentration range and 0.171 μA μM-1 cm-2 for the higher concentration range. The Ni/PDDA/rGO sensor also showed excellent anti-interference ability and good long-term stability. The purposed disposable sensor was successfully applied to determine nitrite in sausages and pickled vegetable samples with satisfactory recovery.