Adsorption-catalysis Integrated Au@ZIF-8 for Structural Detoxification and Trace Detection of Nitro Impurities

Abstract

Nitro-containing impurities pose severe threats to pharmaceutical safety due to their pronounced oxidative toxicity and carcinogenic potential. Its detoxification conversion and trace detection are of great significance. Conventional pretreatment strategies typically rely on either adsorption or catalytic conversion, limiting overall purification efficiency. Herein, we present an Au@ZIF-8 composite that integrates high-capacity adsorption with catalytic detoxification in a single platform while concurrently enabling mass spectrometric signal amplification. The uniform confinement of Au nanoparticles (AuNPs) within the Zeolite imidazole ester skeleton ZIF-8 framework enhances surface area and pore accessibility, while interfacial electronic coupling between Au and the framework generates electron-deficient Au⁺ sites that facilitate hydrogen activation and nitro group reduction. Using 4-nitrophenol (4-NP) and N-nitrosodimethylamine (NDMA) as representative N-nitroso impurities, Au@ZIF-8 demonstrates rapid adsorption–catalysis synergy, converting 4-NP to 4-aminophenol (4-AP) within 15 minutes and catalytically hydrogenating NDMA to dimethylamine (DMA) under mild conditions. This transformation converts a weakly ionizable carcinogen into a readily ionizable derivative, boosting an approximately 50-fold enhancement in LC–MS/MS detection sensitivity. Collectively, this dual-function material establishes a versatile adsorption–catalysis–derivatization platform that couple chemical detoxification with analytical signal amplification, offering a new paradigm for the trace impurity control and environmentally friendly pharmaceutical analysis.