the spot test carried on filter paper strips appears as a very suitable technique to investigate the reactivity of catalases , peroxidases , porphyrins ( bilirubin and protoporphyrin ) , metalloporphyrins ( haemoglobin , haemin , haematin , chlorophyll and cyanocobalamin ) , ferric and ferrous salts .
C0032712
porphyrins
C0025541
metalloporphyrins