Abstract: A new optical sensor for the determination of picric acid based on reversible fluorescence quenching of anthracene dissolved in plasticized poly(vinyl chloride) membrane has been developed. The optimum membrane of the sensor consists of 6～8mg anthracene, 50mg PVC,100mg bis(2-ethylhexyl)phalate. With the optimum membrane described, picric acid in sample solutions from 3.04×10^-6mol/L to 6.16×10^-3mol/L can be determined. Besides a high reproducibility of the optical signals,the very short response times of less than 40s are realized. The sensor has a good selectivity, common hydrophobic anions do not interfere the determination. The sensor has been applied to indirect determination of some drugs, such as quinine, cinchonine, with satisfactory results.

Key words: picric acid, optical sensor, anthracene, pharmaceutical analysis