Selective optode for o-mononitrophenol based on fluorescence quenching of a conjugated polymer

A Selective optode for o-mononitrophenol has been developed based on fluorescence quenching of a conjugated polymer -poly(2,5-dimethoxy-phenyldiacetylene) (PDPA) (399nm/446nm), which was incorporated in a plasticized poly(vinyl chloride) (PVC) membrane. Conjugated pi-electrons of PDPA exhibits high lipophilicity, intense fluorescence and other collective properties different from small molecule element. It can be used as a sensing material (probe) to indicate the presence of an electron-poor analyte. Compared with those small molecules as sensing materials incorporated in optode, PDPA shows improving stability in PVC membrane. With the optimum condition described, o-NTP can be determined from 1.8×10-6 to 1.8×10-3moll-1. The response time of the sensor is within 1.0min. In addition to the high reversibility of the fluorescence signal, the sensor also exhibits good selectivity over other nitrophenols and common ions except for Hg2+.