<p>Lead contamination in water poses a serious environmental and public health risk due to its persistence, bioaccumulation, and toxicity even at trace levels. Carbon-based materials have attracted considerable attention as electrode modifiers for electrochemical sensors because of their high electrical conductivity and tunable surface chemistry. Among them, hydrothermal carbons produced from biomass precursors offer a cost-effective and sustainable platform with controllable surface functionalities. However, the influence of precursor structure on the electrochemical performance of hydrothermal carbon-based sensors remains insufficiently understood. In this study, hydrothermal carbon materials synthesized from the structurally distinct saccharide-based precursors glucose, β-cyclodextrin, and starch were comparatively investigated as electrode modifiers for lead(II) detection using square wave anodic stripping voltammetry. Among the prepared sensors, the β-cyclodextrin-derived hydrothermal carbon modified glassy carbon electrode exhibited superior analytical performance, achieving a limit of detection of 5.0&#xa0;nM and a wide linear working range of 0.01–117.8&#xa0;µM. The developed sensors demonstrated good repeatability and reproducibility (relative standard deviation below 5%) and excellent selectivity against common interfering metal ions, and their practical applicability was verified through tap water analysis with recovery values close to 100%. These findings highlight the critical role of rational precursor selection in the design of high-performance hydrothermal carbon-based electrochemical sensors for heavy metal monitoring.</p> Graphical abstract <p></p>