A newly developed electrochemical sensor for determination of hydrogen peroxide (H 2 O 2 ) in beverages using a water-insoluble picket-fence porphyrin (FeTpivPP) functionalized multiwalled carbon nanotubes (MWNTs) is demonstrated. Introduction of FeTpivPP on MWNTs led to enhanced electron transfer. As a new platform in electrochemical analysis, the resultant sensor showed excellent electrocatalytic activity toward the reduction of H 2 O 2 due to the synergic effect between MWNTs and FeTpivPP, thus leading to highly sensitive amperometric sensing of H 2 O 2 with a detection limit of 0.05 mmol L
À1. The developed method is successfully used to detect H 2 O 2 in beverages and shows great promise for routine sensing applications.