The scopoletin assay for hydrogen peroxide. A review and a better method.

Scopoletin, 7-hydroxy-6-methoxy-2H-1-benzopyran-2-one, a naturally occurring component in cotton leaf and citrus peel is a fluorescent substrate for peroxidase which has been used by many investigators for the determination of hydrogen peroxide concentration. The technical details of these investigations are application-specific and rather critical, making it difficult to apply the scopoletin assay to alternative systems without extensive modification. Although such factors as interfering substances and optimum conditions have been discussed in many publications, these discussions tend to be application-specific. The present paper attempts to provide a technical review of scopoletin applications, add a few new experimental observations, and discuss general parameters which must be carefully controlled for reliable results.