AgBiS2 embedded activated graphene nanolayer for sensing azathioprine in biospecimens

The residues of drugs from the pharmaceutical industry and hospital waste have serious impacts on the environment and public health due to their high toxicity and non-biodegradability. Sensitively detecting drugs residues in environmental and pharmaceutical contexts is crucial. In this work, silver bismuth sulfide (AgBiS2) acacia-like nanoflowers were synthesized via an in-situ hydrothermal process. The activated graphene (AGr) nanolayer was prepared using an environmentally friendly dry ball-milling method, achieving a high yield of up to 95%. Furthermore, AgBiS2 was reinforced with AGr using the ultrasonication method. The composite formation and morphological structure of the AgBiS2/AGr composite were analyzed using various analytical and spectroscopic techniques, including XRD, XPS, FE-SEM, and TEM. The AgBiS2/AGr composite-modified glassy carbon electrode (GCE) exhibited irreversible cathodic currents for the detection of azathioprine (AZP) through both cyclic voltammetry (CV) and amperometric techniques (i-t). Under optimized conditions, the developed AZP sensing demonstrated a linear range of 20 nm to 17.44 µM, with a limit of detection (LOD = 0.007 µM), a sensitivity of 5.7142 µA µM−1cm−2, and high specificity. Besides, the proposed sensor for the detection of AZP in biological samples (blood and urine) achieving satisfactory recovery rates.