Conversion of biomass into porous carbon materials for efficient electrochemical detection of ornidazole

The conversion of biomass into high-value carbon materials presents significant opportunities for electrochemical sensing due to their large specific surface area, abundant pore structure as well as prominent electrical conductivity. In this study, a high-performance electrochemical sensor based on waste biomass was developed for the rapid detection of ornidazole (ODZ). After systematically screening various biomass materials, including crab shell, pine nut shell, pig bone, and mandarin orange peel along with their respective activation methods, it was determined that H₃PO₄-activated pine nut shell (P-PNS) served as the optimal precursor. Under a nitrogen atmosphere, the porous biomass derived carbon material P-PNS-800 was synthesized by heating at a rate of 5 °C min^-1 to 800 °C and maintaining it for 2 hours. The morphological and structural characteristics of pine nut shell-derived carbon at varying pyrolysis temperatures were analyzed using SEM, XRD, FT-IR and nitrogen adsorption-desorption techniques. The results demonstrated that during high-temperature carbonization, the synergistic effects of lignin decomposition and polyphosphate bond volatilization led to the formation of a highly defective carbon skeleton with a specific surface area of 1317.84 m² g^-1. The material exhibited superior electrocatalytic performance toward ODZ, obtaining a wide linear range of 0.20-150 μM, a high sensitivity of 0.48 μA μM^-1, and a limit of detection as low as 0.05 μM (S/N = 3). When applied to ornidazole tablets, the results were in good accordance with those obtained by HPLC, confirming the promising application potential of biomass-derived carbon materials in the field of electrochemical sensing. This work offers a significative strategy for the utilization of waste resources and the detection of antibiotics.