Mediatory determination of antihypertensive drug nifedipine on glassy carbon electrode modified with novel ferrocene based ionic liquid

Ionic liquids (ILs) are liquids containing solely ions with melting points lower than 100 °C 1. One of the attractive attributes of ILs is the potential to generate a wide range of types of ILs with fine-tuned physicochemical properties by the combination of various cations with anions, along with rational functionalization of ions 2. The idea of task-specific ionic liquids (TSILs) carrying specific functionality tailored for certain applications has become more popular, and an impressive catalog of TSILs with pendant acid, base, alcohol, or ether groups on one (or both) of the ions are recently synthesized 2. Ferrocene is an organometallic compound which has been used as an effective redox mediator for the electrocatalytic oxidation of various substrates due to its unique electrochemical behavior 3. Therefore, combination of unique characteristic of ionic liquids and ferrocene by synthesizing ferrocene based ionic liquids could be beneficial. Nifedipine, known as a calcium channel blocker, is widely used in the treatment of cardiovascular diseases such as hypertension and angina pectoris. However, high doses are toxic and can result in heartbeat, nausea, vomiting, etc, so the sensitive and accurate detection of nifedipine is required. Recently, electrochemical methods were proved to be effective for nifedipine determination 4. In the present study, the N-(1-methyl imidazolium)-propyl ferrocene sulfonamide tetra fluoroborate ionic liquid was synthesized and applied for surface modification of glassy carbon electrode. Then, this modified electrode was used for mediatory electrochemical determination of antihypertensive drug nifedipine. Cyclic voltammetry was explored to investigate preliminary experiments, optimization of effective parameters on electrode performance and studding kinetic parameters of modified electrode. By using hydrodynamic amperometry as sensitive method the calibration curve was plotted in the concentration range of 3 nM to 110 nm. The detection limit was calculated as 1 nm based on signal to noise ratio of 3. Lastly, the present method was applied to determine nifedipine in urine and plasma samples which was taken from patients who was administrated nifedipine tablet and satisfactory results were obtained with good accuracy.