Determination of berberine in pharmaceutical preparations using acidic hydrogen peroxide-nitrite chemiluminescence system.

A stronger chemiluminescence (CL) was observed when hydrogen peroxide was mixed with nitrite and berberine in sulfuric acid solution. The stronger CL originated from peroxidation of berberine by peroxynitrous acid that was synthesized online by the mixing of acidic hydrogen peroxide solution with nitrite solution in a flow system. The emitting species was excited state oxyberberine, a peroxidized product of berberine. Based on the stronger CL, a flow injection CL method for the determination of berberine was proposed. Under optimum experimental conditions, the stronger CL intensity was linearly related to the concentration of berberine over the range of 2.0 × 10(-7) -2.0 × 10(-5) mol L(-1) . The limit of detection (s/n = 3) was 6.2 × 10(-8) mol L(-1) . The proposed method has been evaluated by analyzing berberine in pharmaceutical preparations.