A PICRIC ACID SENSING MEMBRANE-BASED ON F LUORESCENCE QUENCHING OF FLUORANTHENE

A new fluorescent sensing membrane for the determination of picric aci d based on reversible fluorescence quenching of fluoranthene dissolved in plasticized poly (vinyl chloride) membrane has been developed. The optimum membrane consists of 1 approximately 6mg fluoranthene, 50mg P VC, 100mg bis(2-ethylhexyl)phalate. With the optimum sensing membrane described, picric acid in sample solution from 1.78 x 10(-6)mol.L-1 to 1.28 x 10(-3)mol.L-1 can be determined. Besides a high reproducibilit y of the optical signals, the very short response times of less than 3 0s are realized. The membrane has good selectivity, many usual hydroph obic anions don't interfere. The proposed method has been applied to i ndirect determination of cinchonine with satisfactory results.