Determination of riboflavin by the perturbation of active oxygen on a chemical oscillating reaction Original Research Article

This paper studies the perturbation of active oxygen (O2radical dot−→H2O2) produced from the irradiated riboflavin on a chemical oscillating reaction, and a new and sensitive methodological approach for the determination of riboflavin is proposed based on it. An automatic experimental setup is designed to combine the irradiation of riboflavin with the analogous Belousov–Zhabotinskii reaction, which is implemented in a continuous-flow stirred tank reactor (CSTR). The oscillator of Mn (II)-catalyzed reaction between diacetone and potassium bromate in acidic medium is used to evaluate the perturbation effect. The presence of active oxygen inhibits the oscillation and results in a longer oscillating periods. The change of the oscillating period is linearly proportional to the concentration of riboflavin over the range 6.5×10−9∼1.2×10−7 mol/l, with a detecting limit of 2.4×10−9 mol/l. Potential and spectrophotometric methods are used to monitor the reaction. Influence of experimental variables on the perturbation is investigated and the possible mechanism of the action of active oxygen on the oscillating system is discussed.