A new fluorescence method for determination of ozone in ambient air

摘要

A new simple method for determination of ozone in ambient air is presented. The reaction employed is based on the known ozonolysis of indigo dye. The indigotrisulfonate molecule contains one carbon-carbon double bond (C C), which reacts with ozone and generates isatinsulfonates and sulfoanthranilate. The quantitatively formed sulfoanthranilate presents fluorescence (Λ_(ex) 245nm, Λ_(em) 400nm). Ozone was collected using two cellulose filters coated with 40 μL of 1.0×10~(-3)molL~(-1) of indigotrisulfonate. The analytical response was linear in the range 0-150 ppbv ozone, and a detection limit of 7 ppbv was achieved using a sampling time of 15min and an optimum sampling air flow rate of 0.4Lmin~(-1). There was no interference from sulfur dioxide, formaldehyde or nitrogen dioxide. The ozonolysis mechanism and the reaction products are discussed.