Hierarchical Iron, Cobalt, and Nickel Sulfide Nanostructures for Simultaneous Quantification of Acetaminophen and Codeine

Hierarchical transition-metal sulfide (HTMS) nanostructures comprising Fe, Co and Ni were synthesized via a facile hydrothermal approach to develop electrochemical sensing platforms for the simultaneous quantification of acetaminophen (ACT) and codeine (COD). Highly crystalline FeS2, CoS and NiS nanostructures were interconnected and self-assembled into hierarchical architectures with rough and porous surfaces, providing abundant accessible active sites. Among the synthesized HTMS, the FeS2 modified screen-printed electrode (FeS2/SPE) exhibited excellent electrocatalytic performance and superior charge-transfer kinetics toward the oxidation of ACT and COD. Differential pulse voltammetry (DPV) revealed well-resolved oxidation peaks for ACT and COD at 0.66 and 1.23 V vs Ag/AgCl, respectively, enabling their simultaneous determination without significant interferences. The FeS2/SPE showed broad linear detection ranges of 0.5−521 μmol/L for ACT and 0.99−566 μmol/L for COD, with correlation coefficients (R2) of 0.989 and 0.982 and low detection limits of 123 and 240 nmol/L, respectively. The FeS2/SPE exhibited high reproducibility, long-term stability, good selectivity and satisfactory recoveries of 94.32.6% and 100.6% in spiked serum and urine samples, respectively. The simply prepared FeS2/SPE provides an inexpensive, portable and sensitive enzyme-free electrochemical sensing platform with promising potential for pharmaceutical and biomedical applications.