Hydroxythiophene-bearing benzothiazole: Selective and sensitive detection of periodate and its application as security ink

Abstract A hydroxythiophene-bearing benzothiazole ( HB ) in phosphate buffer solution showed strong yellow fluorescence emission, which selectively and sensitively decreased by addition of IO 4 − . The reaction between HB and IO 4 − dramatically accelerated by UV irradiation. The fluorescence emission of HB was gradually recovered upon thermal heating of the IO 4 − -adducted product, indicating IO 4 − release. Using these properties, the solution containing HB and IO 4 − has been used as a fluorescence-based security ink.