To build a portable and sensitive method for monitoring the concentration of the flavonoid rutin, a new electrochemical sensing procedure was established. By using nitrogen-doped carbonized polymer dots (N-CPDs) anchoring few-layer black phosphorene (N-CPDs@FLBP) 0D-2D heterostructure and gold nanoparticles (AuNPs) as the modifiers, a carbon ionic liquid electrode and a screen-printed electrode (SPE) were used as the substrate electrodes to construct a conventional electrochemical sensor and a portable wireless intelligent electrochemical sensor, respectively. The electrochemical behavior of rutin on the fabricated electrochemical sensors was explored in detail, with the analytical performances investigated. Due to the electroactive groups of rutin, and the specific π-π stacking and cation–π interaction between the nanocomposite with rutin, the electrochemical responses of rutin were greatly enhanced on the AuNPs/N-CPDs@FLBP-modified electrodes. Under the optimal conditions, ultra-sensitive detection of rutin could be realized on AuNPs/N-CPDs@FLBP/SPE with the detection range of 1.0 nmol L⁻¹ to 220.0 μmol L⁻¹ and the detection limit of 0.33 nmol L⁻¹ (S/N = 3). Finally, two kinds of sensors were applied to test the real samples with satisfactory results.

In this paper, graphdiyne (GDY)−modified glassy carbon electrode was prepared and further used for the sensitive and simultaneous detection of three target heavy metal ions of Zn²⁺, Cd²⁺ and Hg²⁺ by codeposition with Bi³⁺ in the mixture solution. GDY−modified electrodes exhibit a larger electrode area and abundant active sites, which is favorable for absorbing more metal ions. Bismuth has low toxicity and can form alloys with zinc, cadmium and mercury. Therefore, three kinds of heavy metal ions can be pre-concentrated with bismuth on the GDY−modified electrode surface, and the following stripping analysis results in high sensitivity and selectivity. By using differential pulse anodic stripping voltammetry, the detection ranges of Zn²⁺, Cd²⁺ and Hg²⁺ were from 2.0 to 100.0 μM with low detection limits of 0.255 μM, 0.367 μM and 0.796 μM, respectively. In addition, the sensor showed excellent repeatability, reproducibility, and stability, which was applied to sensitive analysis of river water samples with satisfactory results.

In this paper, a highly conductive alkali-activated graphitized carbon (a-GC) was prepared using tilapia fish scales as precursors through enzymolysis, activation and pyrolytic carbonization methods. The prepared a-GC was modified on the surface of a screen-printed carbon electrode to construct a flexible portable electrochemical sensing platform, which was applied to the differential pulse voltametric detection of dopamine (DA) using a U-disk electrochemical workstation combined with a smart phone and Bluetooth. The prepared a-GC possesses good electrical conductivity, a large specific surface area and abundant active sites, which are beneficial for the electrooxidation of DA molecules and result in excellent sensitivity and high selectivity for DA analysis. Under the optimal conditions, the oxidation peak current of DA increased gradually, with its concentrations in the range from 1.0 μmol/L to 1000.0 μmol/L, with the detection limit as low as 0.25 μmol/L (3S/N). The proposed sensor was further applied to the determination of DA in human sweat samples, with satisfactory results, which provided an opportunity for developing noninvasive early diagnosis and nursing equipment.

The persistent presence of pesticide residues in vegetables raises significant concerns for food safety and public health, highlighting the need for sensing platforms that are efficient, affordable, and environmentally friendly while minimizing analysis time and reagent use. In this study, we developed a laser-induced graphene electrode (LIGE) modified with a titanium dioxide–Enteromorpha-derived carbon composite (TiO₂@EDC) for the sensitive electrochemical detection of the herbicide diuron in vegetables. This integrated system streamlines material synthesis, electrode fabrication, and electrochemical analysis into a single, practical platform for food safety monitoring. Under optimized conditions, this sensor exhibited a wide linear detection range of 0.01 µM to 1 mM, with a low limit of detection of 2.99 nM (3 S/N) and a limit of quantification of 9.98 nM (10 S/N). Notably, the sensor demonstrated excellent analytical performance in real vegetable samples by accurately quantifying diuron residues in lettuce, indicating its potential for on-site monitoring of pesticide contamination in food matrices to ensure food safety.