title: A selective PVC membrane for di- or trinitrophenol based on N,N-dibenzyl-3,3',5,5'-tetramethylbenzidine.
abstract: A new fluorophore, N,N-dibenzyl-3,3',5,5'-tetramethylbenzidine (NBTMB), was prepared and shown to exhibit significant and analytical usefulness for optical sensing toward 2,4-dinitrophenol or 2,4,6-trinitrophenol (picric acid) when it was immobilized in a plasticized poly(vinyl chloride) (PVC) membrane. When the membrane was applied to aqueous nitrophenol solution, NBTMB was able to extract selectively nitrophenol into the membrane phase. Since the extraction equilibrium was accompanied by fluorescence quenching of NBTMB, the chemical recognition process could be directly translated into an optical signal. The sensor showed reversible response in the concentration range from 2.0 x 10(-7) to 6.0 x 10(-5) mol L(-1) for the detection of 2,4-dinitrophenol in NaOAc-HOAc buffer at pH 4.0. It also showed a fast response time (t95% < 1.5 min) when the sensor was applied to 2,4-dinitrophenol solution at concentration levels of 5.26 x 10(-6) and 2.10 x 10(-5) mol L(-1) alternatively. A working principle is proposed and the responses of this sensor to various kinds of nitrophenol were studied. The sensor was applied to the direct determination of 2,4-dinitrophenol in prepared water samples and the indirect assay of the drug cinchonine and the results obtained were satisfactory.
authors.affiliation: College of Chemistry and Chemical Engineering, Hunan University, Changsha, China.
authors.forename: Rong Hua
authors.initials: RH
authors.lastname: Yang
authors.forename: Ke Min
authors.initials: KM
authors.lastname: Wang
authors.forename: Li Ping
authors.initials: LP
authors.lastname: Long
authors.forename: Wing Hong
authors.initials: WH
authors.lastname: Chan
authors.forename: Xiao Hai
authors.initials: XH
authors.lastname: Yang
mesh_terms: D019297:2,4-Dinitrophenol / Q000032:analysis; D002930:Cinchona Alkaloids / Q000032:analysis; D004785:Environmental Pollutants / Q000032:analysis*; D008567:Membranes, Artificial; D009596:Nitrophenols / Q000032:analysis*; D011143:Polyvinyl Chloride; D013053:Spectrophotometry
chemical_list: D002930:Cinchona Alkaloids; D004785:Environmental Pollutants; D008567:Membranes, Artificial; D009596:Nitrophenols; D011143:Polyvinyl Chloride; D019297:2,4-Dinitrophenol; C010086:cinchonine