Rapid analysis of quinoxalines in feeds by a fluorescence sensor based on tetraphenylmethane porous organic framework membrane

In this work, a tetraphenylmethane porous organic framework ( TPOF ) membrane was prepared by mixing fluorescent TPOF into poly (vinylidene fluoride) (PVDF). Combining the advantages of membrane and TPOF , the TPOF membrane exhibited a continuous porous structure , good flexibility, hydrophobic properties and excellent fluorescence performance. Owing to the remarkable selectivity towards quinoxalines , the TPOF membrane was used as a fluorescence sensor for rapid quinoxalines analysis. The mechanism of the TPOF selectivity was studied by density functional theory (DFT) calculation experiments. Compared to other growth promoting drugs, the lowest unoccupied molecular orbital (LUMO) energy state difference between TPOF and quinoxalines was the largest. The linear ranges for the determination of carbadox and olaquindox were 0.3–20.0 and 0.6–20.0 μmol/L with the correlation coefficients (R 2 ) of 0.9904 and 0.9943, respectively. The limit of detection (LOD, S/N  = 3) were 96 and 182 nmol/L , respectively. Furthermore, this fluorescence sensor was used for olaquindox determination in feed samples, and the recoveries were varied from 97.4% to 107.7%. The results obtained by the proposed fluorescence method showed a good agreement with that obtained from HPLC method. Overall, this fluorescence sensor has been confirmed excellent performance in the quinoxalines analysis, which reveals extensive application in rapid residual quinoxalines analysis in feed samples.