Guayaconico procedure to produce acid, acid and guayaconico Diagnostic Medium containing

摘要

The invention provides a diagnostic agent for the detection of occult blood in feces comprising hydrogen peroxide and, as a chromogen, guaiaconic acid A, optionally with a stabilizer. The invention provides, as a novel substance, guaiaconic acid A having a specific extinction E1 cm1% at 600 nm of at least 200, determined by the reaction with peroxidase and hydrogen peroxide, having infra-red bands at 1600 cm-1 (m); 1505 cm-1 (v.s.); 1206 cm-1 (s;b); 1115 cm-1 (m); 1025 cm-1 (m); and 1200 cm-1 (s;b) and having an RF value of 0.45 (toluene/dioxan/glacial acetic acid; 90:25:10 v/v/v).