Screen printed carbon electrode modified with WS2 nanosheet incorporated with cobalt oxide for non-enzymatic detection of lactic acid

Lactic acid is an essential organic chemical in food, clinical, chemical, and bioprocessing industries. The non-enzymatic sensor also possesses satisfactory stability and repeatability. Herein we report the WS2/CO3O4 Composite has been prepared via facile cost-effective solid state & hydrothermal method. X-ray diffraction (XRD), Fourier- transform infrared spectroscopy (FT-IR), and Field emission scanning electron microscopy (FE-SEM) have been used to examine the facets, oxidation states and morphology respectively. The electrochemical activity of WS2/Co3O4 was investigated by cyclic voltammetry and amperometric measurement in 0.1 M NaOH. The high electrochemical activity towards the oxidation of lactic acid in a 0.1 M NaOH solution with fast response time of 5 s has been obtained using WS2/CO3O4. As well, EIS of WS2/CO3O4 shows the low charge transfer resistance compared to WS2 and Co3O4. The proposed non-enzymatic sensor shows a linear range of 50–1000 µM with a low detection limit of 6 µM for lactic acid detection. Moreover, the sensor shows excellent selectivity in the presence of interfering species such uric acid (UA), ascorbic acid (AA), dopamine (DA), Mg2+, and Ca2+ and lactic acid (LA). These molecules did not produce a remarkable current response. The real word application of as prepared WS2/Co3O4 sensor is tested in urine sample with an acceptable recovery of 97.01–100.03%.