A selective PVC membrane for di- or trinitrophenol based on N,N-dibenzyl-3,3',5,5'-tetramethylbenzidine.
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.
Yang
Rong Hua
RH
College of Chemistry and Chemical Engineering, Hunan University, Changsha, China.
Wang
Ke Min
KM
Long
Li Ping
LP
Chan
Wing Hong
WH
Yang
Xiao Hai
XH
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
D002930:Cinchona Alkaloids; D004785:Environmental Pollutants; D008567:Membranes, Artificial; D009596:Nitrophenols; D011143:Polyvinyl Chloride; D019297:2,4-Dinitrophenol; C010086:cinchonine