In situ electrochemical determination of labetalol cardiac medicine in blood serum by a nanomodified electro-sensor

Labetalol is a mixed α- and β-adrenoceptor-blocking antagonist that blocks the action of epinephrine on blood vessels and the heart. Labetalol therapy at high dosages has shown hepatotoxicity and renal failure. Developing a rapid, precise method for direct labetalol detection in blood has been investigated based on the electrodeposition of zinc nanoparticles and 4-aminobenzonitrile on graphite electrodes by cyclic voltammetry. Square‑wave voltammetry was used to evaluate the electroactive layers’ performance. The target electrode has a high electrocatalytic characteristic for the irreversible electro-oxidation of labetalol. The electron transfer coefficient was equal to 0.88, with an electron transfer rate of 2.94 s–1, and the saturated adsorptive capacity of the electroactive substance was equal to 1.5 × 10–8 mol cm–2. Scanning electron microscopy of the electrode revealed the nanostructure of the electrodeposited films. This sensor is capable of labetalol determination over the 30 to 300 nmol L–1 range, with a detection limit of 9.83 nmol L–1 and a quantification limit of 29.78 nmol L–1. The method’s reliability regarding the blood serum samples was checked. The low detection limit, high accuracy, and fast response with no interferences confirm the sensor’s ability to conduct electrochemical in situ direct monitoring of labetalol.