Investigation of Chemiluminescence Behavior of Flavonoids with Cerium (IV)‐Rhodamine B System

Abstract

The chemiluminescence (CL) behavior of five major flavonoid types in cerium (IV)‐rhodamine B system was investigated by flow‐injection. Strong CL was observed when cerium (IV) reacted with rhodamine B in sulfuric acid medium in the presence of flavonoids. This reaction system has been established as a simple, rapid, and highly sensitive flow injection CL analysis for quercetin and kaempferol, and their detection limit (3σ) was 2.7 and 0.22 nmol/L, respectively. The relative standard deviation (n=8) was 1.2% for 1.0 µmol/L quercetin and 1.9% for 0.5 µmol/L kaempferol. This method was successfully applied to the determination of quercetin in the hydrolysate of rutin and compared well with the high performance liquid chromatography (HPLC) method. From a comparison of several related flavonoids, it was concluded that only flavonoids that contain a free 3‐hydroxyl and 2, 3‐double bond in conjugation with 4‐oxo function could produce a relatively strong CL emission.

Keywords:

• Chemiluminescence
• flavonoids
• quercetin
• kaempferol
• cerium (IV)
• rhodamine B

Acknowledgments

This work was supported by the National Natural Science Foundation of China (Grant No. 20075021, 20445002).