A Fluorimetric Method for the Determination of Atmospheric Sulphur Dioxide With 2′, 7′—Dichlorofluorescein∗

Abstract
A rapid, simple and sensitive fluorimetric method has been developed for the determination of atmospheric sulphur dioxide with dichlorofluorescein as fluorogenic reagent (λex = 505 nm, λem = 520 nm) at pH 4.0–6.0. A linear calibration curve was obtained in the range 0.01–0.40 μg SO2/25 ml. The detection limit is 0.01 μg SO2/25 ml. Nitrogen dioxide does not interfere with the method. The method was successfully applied to the determination of atmospheric sulphur dioxide.