Abstract
•Thulium metal-organic framework (Tm-BTC MOF): synthesis & characterization.•Tm-BTC MOF is as an excellent electrocatalyst for roxarsone, LOD:100 Pm.•Practically verified in chicken and beef extracts.•First smartphone integrated electrochemical sensor for roxarsone.•The method can be used for roxarsone analysis in resource-limited settings.
A portable sensor is needed for the quick screening of additives in food samples, to ensure food safety. The consumption of roxarsone (ROX) contaminated meat increases arsenic toxicity, risk of cancer and neurodegenerative diseases. In this research work, we report the synthesis of thulium (III)-benzene 1,3,5-tricarboxylic acid-based metal-organic framework (Tm-BTC MOF) and its use as an excellent electrocatalyst for the determination of ROX at point-of-care. A hydrothermal procedure was developed for the synthesis of Tm-BTC MOF using a single polarity solvent. A Tm-BTC MOF modified electrode was fabricated and its electrocatalytic sensing ability towards ROX was explored. Three kinds of special chemical interactions form a special affinity between ROX and Tm-BTC MOF. In association with differential pulse voltammetry, the Tm-BTC MOF/GCE showed a low detection limit of 100 pM. The Tm-BTC MOF modified electrode was integrated into a portable sensing device via coupling it with a miniaturized potentiostat (KAUSTat) operated wirelessly by a smartphone. The developed smartphone-based sensor was successful in measuring ROX not only in lab samples but also in real (spiked) food samples. The method can be suitable for on-site testing of food quality and safety in resource-limited settings.
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