عنوان مقاله [English]
In this work, a nanosensor for Cu(II) and ascorbic acid (AA) based on anti-aggregation and aggregation mechanisms of gold is proposed. In the first part, a selective method for Cu2+ based on the anti-aggregation process of gold nanoparticles by neocuproine (NC) is proposed. In the presence of a constant concentration of NC, Cu(II) decreases the aggregation of gold nanoparticles by forming a four-dentate complex with NC. The anti-aggregation process of gold nanoparticles is performed in the range of 5-500 nM of Cu(II). A value of detection limit of 1 nM is estimated for Cu(II). This is lower than the allowable levels of Cu(II) in drinking water. The results revealed that the proposed method shows good selectivity for Cu(II) compared to other ions to decrease the aggregation of gold nanoparticles. The proposed method for Cu(II) is employed in drinking water samples. In the second part, the anti-aggregation process of gold nanoparticles is used for AA. AA as a competitive ligand with NC for Cu(II) enters the anti-aggregation process of gold nanoparticles and can react with it by removing Cu(II) from the NC- Cu(II) complex. During this, AA is oxidized and Cu(II) is converted to Cu(I). Rereleasing of NC from the complex causes re-aggregation of nanoparticles. The aggregation is performed in the range of 9-75 nM of AA. The result of this competition was to measure AA with high selectivity and a detection limit of 1.8 nM. This method is used to measure AA in a sample of vitamin C tablet.