A reusable optical sensing layer for picric acid based on the luminescence quenching of the Eu—thenoyltrifluoroacetone complex

A new luminescene sensing layer for the determination of picric acid based on reversible luminescence quenching of the Eu-thenoyltrifluoroacetone (TTA) complex was proposed. The optosensor was based on the electrostatic immobilization of the Eu—TTA complex on the chelating resin of Chelex 100 packed in the flow cell, which can induce a room temperature luminescence behaviour in an aqueous phase. The quenching mechanism was also studied. The detection limit was 2 × 10−6 M by using a response time of 1 min. The optosensor was easy to prepare and the lifetime of the optosensor was at least 1 month. The optosensor has been used for the direct determination of picric acid in water samples and the indirect measurement of some drugs such as quinine.