A new kind of carbazole-based photorefractive polymer was prepared via a post-azo- coupling reaction. The structure of the polymer was characterized by IR, 1H NMR, UV-vis and GPC. The IR and UV-vis spectra demonstrate...A new kind of carbazole-based photorefractive polymer was prepared via a post-azo- coupling reaction. The structure of the polymer was characterized by IR, 1H NMR, UV-vis and GPC. The IR and UV-vis spectra demonstrated that azo group was grafted to the polymer in content of 15.56%. The molecular weight of the polymer as determined by GPC was higher than that of the polymer obtained by common method.展开更多
In the acid medium,nitrite can diazotize with p-nitroaniline（PNA）and then couple with diethyl malonate（DM） in basic medium to produce an azo compound,which has the maximum absorption at 496 nm and a molar absorpti...In the acid medium,nitrite can diazotize with p-nitroaniline（PNA）and then couple with diethyl malonate（DM） in basic medium to produce an azo compound,which has the maximum absorption at 496 nm and a molar absorptivity(ε496) of 1.7×104L·mol-1·cm-1.A new spectrophotometric approach for nitrite determination was established on such basis with a detection limit of 1.7×10-7 mol/L.Beer’s law was obeyed in the concentration range of 0.05μg/mL-0.80 μg/mL for sodium nitrite.The proposed method has been applied for the determination of nitrite in vegetables,and the results are satisfactory.展开更多
文摘A new kind of carbazole-based photorefractive polymer was prepared via a post-azo- coupling reaction. The structure of the polymer was characterized by IR, 1H NMR, UV-vis and GPC. The IR and UV-vis spectra demonstrated that azo group was grafted to the polymer in content of 15.56%. The molecular weight of the polymer as determined by GPC was higher than that of the polymer obtained by common method.
文摘In the acid medium,nitrite can diazotize with p-nitroaniline（PNA）and then couple with diethyl malonate（DM） in basic medium to produce an azo compound,which has the maximum absorption at 496 nm and a molar absorptivity(ε496) of 1.7×104L·mol-1·cm-1.A new spectrophotometric approach for nitrite determination was established on such basis with a detection limit of 1.7×10-7 mol/L.Beer’s law was obeyed in the concentration range of 0.05μg/mL-0.80 μg/mL for sodium nitrite.The proposed method has been applied for the determination of nitrite in vegetables,and the results are satisfactory.
