Evaluation of Inorganic Element Content and Safety of Selaginellae Herba Carbonisata Based on Different Processing Heating Durations

This study evaluated the inorganic element content and safety of Selaginellae Herba Carbonisata under different processing durations, including unprocessed crude drugs (SH-Cr), insufficiently (ISH-Ca), properly (SH-Ca), and excessively processed (ESH-Ca) samples. The contents of 39 elements were analyzed by ICP-MS, and the safety of key heavy metals (Pb, As, Cd, Cu) was assessed using exposure assessment, the Hazard Index (HI), and the Margin of Exposure (MOE). Results showed high concentrations of K, Fe, Mg, and Na, alongside beneficial trace elements (Al, Ca, Mn, Zn). Furthermore, Levels of Mg, K, Ca, Mn, Cu, Zn, Ga, Rb, and Au increased significantly with higher processing temperatures ( P < 0.05). Antimony (Sb) exhibited the highest migration rate, whereas the behavior of others was variable. Although the contents of Pb, Cd, As, and Cu complied with regulatory limits (HI < 1, MOE > 1), the potential introduction of lead and copper during processing warrants attention, highlighting the need to standardize raw materials and processing equipment. SH-Ca was identified as the optimal product due to its balanced elemental profile and safety compliance. In summary, these findings support quality control for carbonized herbal materials and provide insights for their potential applications in functional foods and dietary supplements. • Comprehensive profiling of 39 inorganic elements (including 4 heavy metals) in Selaginellae Herba under different processing durations, revealing temperature-dependent accumulation of Mg, K, Ca, Mn, Cu, Zn, Ga, Rb, and Au ( P < 0.05). • Antimony (Sb) identified as the most migratable heavy metal during carbonization, with dynamic migration patterns quantified for the first time, providing critical data for processing parameter optimization. • Multidimensional safety assessment integrating Exposure Margin (MoE), Hazard Index (HI), and elemental fingerprinting, demonstrating SH-Ca (properly processed) as the safest variant with heavy metal levels compliant to WHO limits (HI <1, MOE >1). • Multivariate analysis revealed distinct differentiation between processed samples, with Ag, Pb isotopes, Sn and Cu being key discriminatory elements (VIP >1).