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Dopamine (DA) is a critical neurotransmitter and has been known to be liable for several neurological diseases. Hence, its sensitive and selective detection is essential for the early diagnosis of diseases related to abnormal levels of DA. In this study, we reported novel molybdenum nanoparticles self-supported functionalized multiwalled carbon nanotubes (Mo NPs@f-MWCNTs) based core-shell hybrid nanomaterial with an average diameter of 40–45 nm was found to be the best for electrochemical DA detection. The Mo NPs@f-MWCNTs hybrid material possesses tremendous superiority in the DA sensing is mainly due to the large surface area and numerous electroactive sites. The morphological and structural characteristics of the as-synthesized hybrid nanomaterial were examined by XRD, Raman, FE-SEM, HR-TEM, EDX. The electrochemical characteristics and catalytic behavior of the as-prepared Mo NPs@f-MWCNTs modified screen-printed carbon electrode for the determination of DA were systematically investigated via electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry. The results demonstrate that the developed DA biosensor exhibit a low detection limit of 1.26 nM, excellent linear response of 0.01 µM to 1609 µM with good sensitivity of 4.925 µA µM−1 cm−2. We proposed outstanding appreciable stability sensor was expressed to the real-time detection of DA in the real sample analysis of rat brain, human blood serum, and DA hydrochloride injection.

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In this work, we describe a facile synthesis of tungsten carbide nanosheets (WC NSs) via hydrothermal approach, and various analytical and electrochemical techniques were used for its characterized. Mercury (Hg II) is one of the most toxic elements that directly and indirectly affects human health and the environment. The optimization condition such as various pHs toward Hg(II) detection was studied. Consequently, in this study, we offer a selective and pico-molar Hg(II) electrochemical sensor in biological and water samples by WC NS modified multi-conventional electrode at 0.16 V (vs. Ag/AgCl). The WC NSs modified SPCE could sense the Hg(II) up 2 to 655 nM. L −1 with the detection limit is 0.18 nM. L −1 . The attained detection limit was well below the guideline level of Hg(II) set by the U.S. Environmental Protection Agency (EPA) and World's Health Organization (WHO). Furthermore, the developed WC NSs modified SPCE selectively determined the Hg(II) in the presence of Cu(II), Pb(II), and Cd(II) as potentially interfering metal cations. The real sample analysis was displayed in human blood serum, fish extract and industrial wastewater samples and obtained results were compared with standard HPLC technique.

We reported Graphene Oxide/α-MnO 2 binary nanosheets (GO/α-MnO 2 BNSs) Based Non-Enzymatic Biosensor for the detection of guanine using selective and ultra-sensitive electrochemical method. In this work, GO/α-MnO 2 BNSs synthesized using simple and cost-effective ultra-sonication method. As produced GO/α-MnO 2 BNSs were investigated by FE-SEM, TEM, EDX, FT-IR, XRD, EIS and electrochemical methods. The electrochemical oxidation behavior of guanine at the GO/α-MnO 2 BNSs modified electrode was evaluated by cyclic voltammetry (CV) while sensitive guanine detection was performed via Differential pulse voltammetry. The as-fabricated biosensor exhibited lower limit of detection was 23.9 (± 0.52) pM with excellent sensitivity about 8.835 (± 0.96) μA μM −1 cm −2 (R 2 = 0.995) and linear range of 50 nM−10.5 μM without surface fouling. The sensor was evidently examined for the detection of guanine in the real sample of DNA to predict unknown concentrations of guanine in the pH 5.0 phosphate buffer.