Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Ar...Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Arsenazo M itself. The apparent molar absorptivity of the BSA-Arsenazo M complex is 3.21105 Lmol-1cm-1. The linear ranges for protein determination are wide (at least 0-100 mg/mL).展开更多
A catalytic spectrophotometry for the determination of trace amount of vanadium was developed based on its catalytic effect on the oxidation of arsenazo by potassium bichromate in weak acidic medium. The optimized co...A catalytic spectrophotometry for the determination of trace amount of vanadium was developed based on its catalytic effect on the oxidation of arsenazo by potassium bichromate in weak acidic medium. The optimized conditions for determinations are: cK2Cr2O7=3.010-5 molL-1, carsenazo =3.010-5 molL-1, pH=4.0, t=90. The calibration graph is linear for 0.020.2 gml-1, and the detection limit is 0.02 gml-1 V. The apparent active energy of this catalytic reaction is 21.72 kJmol-1. Most foreign ions do not interfere with the determination of vadadium, except for Fe() and Co(), and their interferences could be eliminated by ion exchange. The present method has been used to make the determination of vanadium in human hair, tea, potato and wastewater, and the results were satisfactory.展开更多
In the medium of 0.18～1.08 mol·L^(-1) sulfuric acid, cerium(Ⅳ) has the color-fading effect on DBC-arsenazo. The apparent molar absorptivity of the color-fading reaction is ε _(530 nm)=1.03×10~4 L·mo...In the medium of 0.18～1.08 mol·L^(-1) sulfuric acid, cerium(Ⅳ) has the color-fading effect on DBC-arsenazo. The apparent molar absorptivity of the color-fading reaction is ε _(530 nm)=1.03×10~4 L·mol^(-1)·cm^(-1). Beer′s law is obeyed over the range of 1.20～12.0 μg·ml^(-1) of Ce (Ⅳ) which shows a linear relationship with the decrease in the absorbance of the colored solution. The effect of thirty-six coexisting ions was studied. The method was applied to the determination of the trace amount of cerium in water samples and has the advantage of high accuracy and good selectivity.展开更多
The reaction of 5-hydroxyl-7-methoxyflavone（tectochrysin） with bromine obtained 3,6,8-tribromo-5-hydroxy-2,7-dimethoxy-2,3-dihydrochromen-4-one（1）, which was characterized by FT-IR, 1 H-NMR, 13C-NMR, elemental ana...The reaction of 5-hydroxyl-7-methoxyflavone（tectochrysin） with bromine obtained 3,6,8-tribromo-5-hydroxy-2,7-dimethoxy-2,3-dihydrochromen-4-one（1）, which was characterized by FT-IR, 1 H-NMR, 13C-NMR, elemental analysis and X-ray single-crystal diffraction. Complex 1 belongs to the monoclinic system, space group pbca with a = 9.4673（8）, b = 17.9938（15）, c = 21.2004（17） A, V = 3611.5（5） A3, Z = 8, μ = 0.6726 mm^（-1）, Dc = 1.795 g/cm3, F（000） = 2080, the final R = 0.0358 and wR = 0.0644 with I 2σ（I）. The results show that the addition reaction occurs at the carbon-carbon double bond（C2 and C3） of tectochrysin and 1 belongs to dihydroflavone. The reaction mechanism was discussed and the structure revealed that the crystal structure of 1 is stabilized by intramolecular hydrogen bonds and C–Br···π interactions. The antitumor ability of 1 was evaluated against human leukemia cells（K562）, human breast cancer cells（MCF-7） and human lung cancer cells（A549）. 1 exhibited potent antitumor activities against human leukemia cells（K562） with the IC50 values of 18.9 μmol/L.展开更多
文摘Arsenazo M could bind with bovine serum albumin to form a complex in Clark-Lube buffer at pH 2.3 and room temperature, which gives a maximum absorption peak at 625 nm with a red shift of 75 nm compared with that of Arsenazo M itself. The apparent molar absorptivity of the BSA-Arsenazo M complex is 3.21105 Lmol-1cm-1. The linear ranges for protein determination are wide (at least 0-100 mg/mL).
文摘A catalytic spectrophotometry for the determination of trace amount of vanadium was developed based on its catalytic effect on the oxidation of arsenazo by potassium bichromate in weak acidic medium. The optimized conditions for determinations are: cK2Cr2O7=3.010-5 molL-1, carsenazo =3.010-5 molL-1, pH=4.0, t=90. The calibration graph is linear for 0.020.2 gml-1, and the detection limit is 0.02 gml-1 V. The apparent active energy of this catalytic reaction is 21.72 kJmol-1. Most foreign ions do not interfere with the determination of vadadium, except for Fe() and Co(), and their interferences could be eliminated by ion exchange. The present method has been used to make the determination of vanadium in human hair, tea, potato and wastewater, and the results were satisfactory.
文摘In the medium of 0.18～1.08 mol·L^(-1) sulfuric acid, cerium(Ⅳ) has the color-fading effect on DBC-arsenazo. The apparent molar absorptivity of the color-fading reaction is ε _(530 nm)=1.03×10~4 L·mol^(-1)·cm^(-1). Beer′s law is obeyed over the range of 1.20～12.0 μg·ml^(-1) of Ce (Ⅳ) which shows a linear relationship with the decrease in the absorbance of the colored solution. The effect of thirty-six coexisting ions was studied. The method was applied to the determination of the trace amount of cerium in water samples and has the advantage of high accuracy and good selectivity.
基金supported by Youth Backbone Teachers Project Funded by Xianyang Normal University(No.XSYGG201606)Scientific Research Program Funded by Shaanxi Provincial Education Department(No.16JK1822)+3 种基金Natural Science Basic Research Plan Funded by Shaanxi Province of China(No.2016JM5024)Science and Technology Projects of Xianyang City(No.2017k02-19)University Students Research and Innovation Training Program of Xianyang Normal University(No.2017060&201710722003)University Students Research and Innovation Training Program of Shaanxi Province(No.2490)
文摘The reaction of 5-hydroxyl-7-methoxyflavone（tectochrysin） with bromine obtained 3,6,8-tribromo-5-hydroxy-2,7-dimethoxy-2,3-dihydrochromen-4-one（1）, which was characterized by FT-IR, 1 H-NMR, 13C-NMR, elemental analysis and X-ray single-crystal diffraction. Complex 1 belongs to the monoclinic system, space group pbca with a = 9.4673（8）, b = 17.9938（15）, c = 21.2004（17） A, V = 3611.5（5） A3, Z = 8, μ = 0.6726 mm^（-1）, Dc = 1.795 g/cm3, F（000） = 2080, the final R = 0.0358 and wR = 0.0644 with I 2σ（I）. The results show that the addition reaction occurs at the carbon-carbon double bond（C2 and C3） of tectochrysin and 1 belongs to dihydroflavone. The reaction mechanism was discussed and the structure revealed that the crystal structure of 1 is stabilized by intramolecular hydrogen bonds and C–Br···π interactions. The antitumor ability of 1 was evaluated against human leukemia cells（K562）, human breast cancer cells（MCF-7） and human lung cancer cells（A549）. 1 exhibited potent antitumor activities against human leukemia cells（K562） with the IC50 values of 18.9 μmol/L.
