Molybdenum disulfide and strontium titanate modified electrode for sensitive electrochemical sensing of folic acid in biological and pharmaceutical samples

Measuring vitamin B9 or folate levels is crucial to diagnosing anemia, preventing severe birth defects during pregnancy, evaluating nutritional status, and dealing with chronic illnesses. Therefore, in this study, an electrochemical sensor platform was built based on molybdenum disulfide and strontium titanate pencil graphite electrode (MoS 2 @SrTiO 3 /PGE) for folic acid (FA) detection. After synthesis by the hydrothermal method, the MoS 2 @SrTiO 3 nanocomposite was characterized using the scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and energy dispersive X-ray analytical techniques. Cyclic voltammetry, impedance spectroscopy, and differential pulse voltammetry were performed to characterize the electrochemical attributes. The MoS 2 @SrTiO 3 /PGE modified electrode exhibited superior electroactivity with improved sensitivity and selectivity towards the electrochemical oxidation of FA. To accomplish maximum performance, the sensor was optimized under the following conditions: pH = 7.0, time = 20 min, material concentration = 7.0 mM, and scan rate = 75 mV/s. Considering optimal conditions, the peak current of FA displayed a linear response, with a detection limit of 4.5 nM in the range of 0.1 nM to 180 nM. The interference studies were carried out as well, and sensor results were shown to be highly selective in the presence of different interferents and maintained good stability. In addition, the sensing platform was effectively employed for trace detection of FA in real samples (supplement and urine), with favorable recovery percentages of 90-95%, respectively. The developed sensor has the potential to be exploited as a disease biomarker for FA detection in healthcare diagnostics.