Rhodamine-dimethyliminocinnamyl based electrochemical sensors for selective detection of iron (II)

A new dimethyliminocinnamyl linked rhodamine (rhodamine-dimethyliminocinnamyl) (RC) has been explored as an electro-active material to prepare voltammetric and potentiometric sensors for the quantification of Fe (II) ions. In voltammetry, RC shows two anodic peaks at 0.4 V and 0.9 V vs. Ag/Ag+ potential which get quenched and a new cathodic peak appeared at more negative potential (−0.5 V) on addition of Fe (II) which is due to the reduction Fe (II) complex formed with rhodamine dimethyliminocinnamyl. Voltammetric sensor can work within the concentration range of 2.0 × 10−6 to 3.0 × 10−4 M with detection limit of 1.6 × 10−7 M. In potentiometric mode, constructed PVC based solid contact coated graphite electrode (CGE) showed Nernstian slope of 29.4 mV/decade of Fe (II) concentration over a linear range of 1.0 × 10−1 to 1.0 × 10−7 M with detection limit of 7.43 × 10−8 M. In the proposed sensors, negligible interference from alkali, alkaline and transition metal ions have been observed and show outstanding analytical performance with different type of sample matrices.