The　accurate　monitoring　of　sulfide　ion　concentrations　is　vital　for　ensuring　food　safety,　but　current　detection　methods　are　often　cumbersome　and　confined　to　laboratories.　This　study　introduces　an　innovative　paper-based　colorimetric　sensor　that　leverages　the　peroxidase-like　activity　of　cobalt　tetrasulfonate　phthalocyanine　(CoTsPc)　for　rapid,　sensitive,　and　selective　sulfide　ion　quantification.　The　underlying　mechanism　relies　on　the　interaction　between　cobalt　and　sulfide　ions,　modulating　the　catalytic　efficiency　of　CoTsPc　and　triggering　a　visible　color　change　when　3,3′,5,5′-tetramethylbenzidine　(TMB)　and　hydrogen　peroxide　are　present.　By　controlling　solvent　evaporation,　the　reaction　kinetics　are　standardized,　enabling　reproducible　and　accurate　colorimetric　measurements.　Experimental　results　show　that　adding　sulfide　ions　to　the　TMB-H₂O₂　reaction　system　causes　a　gradual　decrease　in　color　intensity　on　the　paper　substrate.　This　change　verifies　effectiveness　of　the　sensor,　highlighting　its　potential　for　reliable　sulfide　ion　detection　in　food　safety　applications,　while　providing　a　simple　and　portable　alternative　to　conventional　methods.　©　2024　Elsevier　Ltd