Electrochemical determination of terbutaline using a SnO₂ nanoparticle-modified carbon paste electrode

Terbutaline hemisulfate (THS), a selective beta-2 agonist, is preferred as a bronchodilator for the treatment of asthma and bronchitis, as well as a tocolytic agent to delay labor in acute situations during premature birth. The use of beta-2 agonists above a certain dose is considered doping in sports competitions. Therefore, it is important that they be determined with high sensitivity and selectivity within a short analysis time. In this study, a SnO₂ nanoparticle-modified carbon paste electrode was developed for the determination of THS. Cyclic voltammetry and differential pulse voltammetry were employed as electrochemical methods. The operating conditions of the developed SnO₂ nanoparticle-modified carbon paste electrode (SnO₂NP/CPE), including the scan rate, SnO₂ nanoparticle content, and pH, were optimized. At the end of the experiments, the optimum operating conditions were determined to be a scan rate of 10 mV/s, 5% SnO₂ nanoparticles, and 0.25 M acetate buffer at pH 4.0. The analytical parameters of SnO₂NP/CPE were also determined. The linear range of the nanosensor was 2.0-50.0 μM, with a limit of detection of 0.55 μM and a limit of quantification of 1.8 μM. In the reproducibility and repeatability tests, the coefficients of variation for 30 μM THS, based on 10 measurements, were 2.58% and 3.30%, respectively. No significant interference from NaCl, glucose, urea, and uric acid was observed in the interference experiments. In contrast, ascorbic acid, dopamine, epinephrine, and citric acid showed slight interference. Comparing the sensor response obtained on the 14th day with the initial peak current value of the nanosensor revealed no change in the nanosensor response, indicating that the developed nanosensor has good storage stability. The developed nanosensor (SnO₂NP/CPE) can be prepared easily and used directly for the determination of THS in samples without additional separation or extraction steps. It is considered suitable for the determination of THS because of its advantages, including good reproducibility and reliability, low cost, and a short response time.