Redox active cobalt-bipyridine metal organic framework-nafion coated carbon nanotubes for sensing ascorbic acid

Redox active cobalt-bipyridine based metal organic framework ([Co(bpy)2NO3]NO3.5H2O = Co-bpy) immobilized on multiwalled carbon nanotubes using Nafion ionomer (GCE/MWCNTs@Co-bpy/Nf) was explored as sensor for ascorbic acid (AA) detection. In order to identify the suitable pH for AA sensing, both sensitivity and detection limit (DL) values were calculated at various pHs and optimum pH identified is 7. To prove the sensing capability of this electrode, real samples like tablets containing AA such as Limcee orange and Celin and Tropicana juices (orange, sweet lime and pineapple) were examined by standard addition approach. In all these samples, the electrode exhibited superior detection with a recovery ranging from 97 (Limcee orange) to 103% (Tropicana Sweet lime).