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Glassy carbon electrodes (GCEs) modified with sulfur‐doped graphene (SG)/carboxylated carbon nanotube (CNT−COOH)/MoS2/yeast composite were prepared for electrochemical detection for lead ions by the simple hydrothermal methods and ultrasonic methods. The combination of SG and CNT−COOH could form a double‐layer carbon structure, providing more active detection sites for detection for lead, which could also contribute to adherence of yeast and MoS2. The SG/CNT−COOH/MoS2/yeast exhibited a high response in detecting low concentrations of lead ions. And then the SG/CNT−COOH/MoS2/yeast was characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), Transmission electron microscope (TEM), Scanning electron microscopy (SEM), and X‐ray photoelectron spectroscopy (XPS). Compared with traditional detection technology, the linear range of the sensor was 10−6∼10−14 g/L. And the lower of detection (LOD) down to 2.61×10−15 g/L was achieved. The sensor showed prospective applications in detection of Pb2+ in real serum samples.

A simple pyrolysis, activation and hydrothermal method was utilized to synthesize composite materials (Fe3O4/SFP) of ferroferric oxide and nitrogen self-doped sunflower plate-derived carbon for the simultaneous electrochemical sensing of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The Fe3O4/SFP had synergistic catalytic effect on target molecules, and the oxidation peak potential of AA, DA and UA was well distinguished in the differential pulse voltammetry determination. Under the optimal conditions, the linear response ranges of AA, DA and UA are 3–150[Formula: see text][Formula: see text]M, 5–450[Formula: see text][Formula: see text]M and 15–1200[Formula: see text][Formula: see text]M, respectively. The detection limits of AA, DA and UA ([Formula: see text]/[Formula: see text]) are 1.0[Formula: see text][Formula: see text]M, 0.4[Formula: see text][Formula: see text]M and 1.48[Formula: see text][Formula: see text]M, respectively, and the sensitivity is 1.87[Formula: see text][Formula: see text] (3–20[Formula: see text][Formula: see text]M) and 0.64[Formula: see text][Formula: see text] (20–150[Formula: see text][Formula: see text]M) for AA, 3.90[Formula: see text][Formula: see text] (5–20[Formula: see text][Formula: see text]M) and 1.21[Formula: see text][Formula: see text] (20–450[Formula: see text][Formula: see text]M) for DA and 1.12[Formula: see text][Formula: see text] (15–100[Formula: see text][Formula: see text]M) and 0.31[Formula: see text][Formula: see text] (100–1200[Formula: see text][Formula: see text]M) for UA. In addition, satisfactory results have been obtained for the determination of AA, DA and UA in normal human serum, which provides a new research direction for the construction of electrochemical sensors in the future.