Application of a hydroxyl functionalized ionic liquid modified electrode for the sensitive detection of adenosine-5′-monophosphate

A new hydroxyl functionalized ionic liquid (IL) 1-(3-chloro-2-hydroxy-propyl)-pyridinium acetate was used as the binder for the preparation of carbon ionic liquid electrode (CILE), which was further used for the voltammetric determination of adenosine-5′-monophosphate (5′-AMP). The modified electrode was characterized by different electrochemical methods including cyclic voltammetry and electrochemical impedance spectroscopy. The results indicated that the presence of IL in the carbon paste greatly improved the electrochemical performances of the modified electrode. A remarkable oxidation peak of 5′-AMP appeared on CILE with the oxidation peak potential of 1.38 V (vs. SCE) at pH 4.0 Britton-Robinson buffer. The electrochemical parameters of 5′-AMP electrooxidation were calculated with the electron transfer coefficient (α) as 0.27, the electron transfer number (n) as 1.11 and the apparent heterogeneous electron transfer rate constant (ks) as 1.03 × 10−5 s−1. Under the selected condition and by using sensitive differential pulse voltammetry the oxidation peak current was proportional to 5′-AMP concentration in the range from 3.0 to 2500.0 μmol/L with the detection limit as 0.60 μmol/L (3σ). The proposed method showed good selectivity to the 5′-AMP detection without the interference from coexisting substances and was further applied to the vidarabine monophosphate injection samples determination with satisfactory results.