Double-sensitive rapid detection of acetic anhydride/propionic anhydride and its practical detection in methamphetamine based on S-doped ZnO nanosheets-assembled flowers

Acetic anhydride is an important ingredient in the manufacture of new psychoactive drugs such as heroin and methamphetamine (ice), and it also produces by-product propionic anhydride in the production. Therefore, the rapid and nondestructive detection of acid anhydride is of great significance in fields such as drug inspection. In this study, S-doped ZnO nanosheets-assembled flowers were prepared by hydrothermal method combined with air oxidation. The sensor showed excellent dual-selectivity to 100 ppm acetic anhydride (S = 13.58) and propionic anhydride (S = 29.48) at 150 °C and 130 °C respectively. The response mechanism of the sensing material to the target gas was explored through various characterizations, such as in-situ FTIR and GC–MS. The analysis results confirmed the catalytic oxidation reaction between acid anhydride and oxygen anions during the sensing process and the final products were verified to be H₂O and CO₂. DFT calculations also confirmed the significant enhancement of adsorption ability of acid anhydride on S doped ZnO, but the negative effect of excessive oxygen vacancy on separation and transfer of charge weakened the adsorption ability of the material for acid anhydride. Furthermore, the sensor's actual application test for methamphetamine showed good application prospects, which is expected to accomplish the primary screening of drugs.