FIA–near-infrared spectrofluorimetric trace determination of hydrogen peroxide using tricarchlorobocyanine dye (Cy.7.Cl) and horseradish peroxidase (HRP)

A new kind of near-infrared fluorescence agent, tricarbochlorocyanine dye (Cy.7.Cl), had been synthesized in house and used for near-infrared spectrofluorimetric determination of hydrogen peroxide (H2O2) by flow injection analysis (FIA) for the first time. The oxidation reaction of Cy.7.Cl with H2O2 occurred under the catalysis of horseradish peroxidase (HRP) and it was studied in detail. The possible reaction mechanism was discussed. Under optimal experimental conditions, fluorescence from Cy.7.Cl displayed excitation and emission maxima (ex/em) at 780 and 800 nm, respectively. The two linear working ranges were 1.86 × 10−7 to 4.11 × 10−7 mol L−1 and 4.11 × 10−7 to 7.19 × 10−6 mol L−1, respectively. The detection limit was 5.58 × 10−8 mol L−1 of H2O2. The effect of interferences was studied. The proposed method was successfully applied to the determination of hydrogen peroxide in rainwater, serum and plant samples.