An anthracene/porphyrin dimer fluorescence energy transfer sensing system for picric acid

The fluorescence energy transfer between anthracene (donor) and 5-p-[[4-(10′15′20′-triphenyl-5′-porphinato) phenyloxyl]-1-butyloxyl] phenyl-10,15,20-triphenyl-porphyrin (DTPP as acceptor) and an optical fiber sensor for the determination of picric acid based on this theory were studied. Because the emission spectrum of anthracene was largely overlapped with the absorption spectrum of the DTPP, the phenomenon of energy transfer occurred when anthracene and DTPP were immobilized in a PVC membrane. The membrane based on anthracene and DTPP contacting with picric acid showed much stronger fluorescence quenching comparing to membranes containing only anthracene or DTPP. The use of DTPP as acceptor was compared with 5,10,15,20-tetraphenylporphyrin (TPP). Both porphyrin compounds can be used as the acceptor, with DTPP clearly preferred. Under optimum conditions, picric acid in a sample solution can be determined from 3.0×10−7 to 2.0×10−3 mol l−1 with a detection limit of 1.5×10−7 mol l−1. The proposed optical fiber sensor shows satisfactory characteristics including good reproducibility, reversibility and selectivity as well as a short response time. The recovery tests of picric acid in industrial wastewaters were satisfactory.