To prepare chiral monomer with single chiral center and higher stereospecificity, a pair of amino-functionalized chiral 3,4-propylenedioxythiophene(ProDOT) derivatives, chiral(3,4-dihydro-2 H-thieno[3,4-b][1,4]dioxepi...To prepare chiral monomer with single chiral center and higher stereospecificity, a pair of amino-functionalized chiral 3,4-propylenedioxythiophene(ProDOT) derivatives, chiral(3,4-dihydro-2 H-thieno[3,4-b][1,4]dioxepin-3-yl)methyl 2-[(tert-butoxycarbonyl)amino]-3-phenylpropanoate(ProDOT-Boc-Phe), were synthesized. Chiral poly[(3,4-dihydro-2 H-thieno[3,4-b][1,4]dioxepin-3-yl)methyl2-[(tert-butoxycarbonyl)amino]-3-phenylpropanoate](PProDOT-Boc-Phe) modified electrodes were synthesized via potentiostatic polymerization of chiral ProDOT-Boc-Phe. Chiral PProDOT-Boc-Phe films displayed good reversible redox activities. The enantioselective recognition between chiral PProDOT-Boc-Phe modified glassy carbon electrodes and DOPA enantiomers was achieved by different electrochemical technologies, including cyclic voltammetry(CV), square wave voltammetry(SWV), and differential pulse voltammetry(DPV).(D)-PProDOT-Boc-Phe and(L)-PProDOT-Boc-Phe showed higher peak current responses toward L-DOPA and DDOPA, respectively.展开更多
The inhibitory effect of ferulic acid on the diphenolase activity of mushroom tyrosinase and the kinetic behavior were studied with L-3,4-dihydroxyphenylalanine （L-DOPA） as substrate. The inhibitor concentration lea...The inhibitory effect of ferulic acid on the diphenolase activity of mushroom tyrosinase and the kinetic behavior were studied with L-3,4-dihydroxyphenylalanine （L-DOPA） as substrate. The inhibitor concentration leading to 50% relative activity lost （IC50） was estimated to be 0.15 mmol·L^-1. The inhibition mechanism obtained from Lineweaver-Burk plots shows that ferulic acid is a competitive inhibitor and the inhibition of tyrosinase by ferulic acid is a reversible reaction. The equilibrium constant for ferulic acid binding with the tyrosinase was determined to be 0.25 mmol·L^-1 for diphenolase. Keywords tyrosinase, ferulic acid, kinetics, inhibition, L-DOPA, diphenolase展开更多
Electroanalytic direct determination of aluminum is a difficult subject because of the highly negative reductive potential of Al(Ⅲ) and interference of H +. But developing methods for the determination of trace amoun...Electroanalytic direct determination of aluminum is a difficult subject because of the highly negative reductive potential of Al(Ⅲ) and interference of H +. But developing methods for the determination of trace amount of aluminum in environmental and biological samples is a hot topic in recent decades owning to the recognition of the potential toxic effects of aluminum. In this paper, the indirect differential pulse voltammetric(DPV) determination of aluminum with L dopa(3,4 dihydroxyphenylalanine) on glass carbon working electrode has been reported. This novel method bases on the linear decrease of DPV anodic peak current of L dopa with the concentration of aluminum added. Under the optimum experimental conditions (pH 8 5, 0 08 mol/L buffer solution, 4×10 -4 mol/L L dopa), the linear range and the detection limit are (2—18)×10 -7 and 7 6×10 -8 mol/L Al(Ⅲ) respectively, the relative standard deviation for 2×10 -5 mol/L Al (Ⅲ) is 2 4%(n=10). A number of foreign species, especially those necessary components in human body such as ascorbic acid, citrate, phosphate, Fe(Ⅲ), Fe(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Ca(Ⅱ) and Mg(Ⅱ) for interference have been studied. Satisfactory recoveries have been obtained by applying this method to determining aluminum in biological samples including mineral water, synthetic renal dialysate, urine and hair. The significance of the method and solutions to possible interference encountered in in vivo detection are discussed. A new direction for further development of the in vivo determination of aluminum is provided in this studies.展开更多
A rapid and sensitive method for analyzing trace b-blockers in complex biological samples,which involved magnetic solid-phase extraction(MSPE)coupled with Fourier transform ion cyclotron resonance mass spectrometry(FT...A rapid and sensitive method for analyzing trace b-blockers in complex biological samples,which involved magnetic solid-phase extraction(MSPE)coupled with Fourier transform ion cyclotron resonance mass spectrometry(FTICR-MS),was developed.Novel nanosilver-functionalized magnetic nanoparticles with an interlayer of poly(3,4-dihydroxyphenylalanine)(polyDOPA@Ag-MNPs)were synthesized and used as MSPE adsorbents to extract trace b-blockers from biological samples.After extraction,the analytes loaded on the polyDOPA@Ag-MNPs were desorbed using an organic solvent and analyzed by FTICR-MS.The method was rapid and sensitive,with a total detection procedure of less than 10 min as well as limits of detection and quantification in the ranges of 3.5-6.8 pg/mL and 11.7-22.8 pg/mL,respectively.The accuracy of the method was also desirable,with recoveries ranging from 80.9%to 91.0%following the detection of analytes in human blood samples.All the experimental results demonstrated that the developed MSPE-FTICR-MS method was suitable for the rapid and sensitive analysis of trace b-blockers in complex biological samples.展开更多
基金the National Natural Science Foundation of China(Nos.51762020 and 51603095)the Natural Science Foundation of Jiangxi Province(Nos.20171ACB20026 and20181BAB206015)+4 种基金the Jiangxi Provincial Department of Education(No.GJJ170662)the Innovation Driven"5511"the Natural Science Foundation of Jiangxi Province(No.20165BCB18016)Students Innovation and Entrepreneurship Training Program(No.20181204066)Projects for Postgraduate Innovation in Jiangxi(No.YC2017-X19)the Jiangxi Provincial Key Laboratory of Drug Design and Evaluation(No.20171BCD40015)for their financial support of this work
文摘To prepare chiral monomer with single chiral center and higher stereospecificity, a pair of amino-functionalized chiral 3,4-propylenedioxythiophene(ProDOT) derivatives, chiral(3,4-dihydro-2 H-thieno[3,4-b][1,4]dioxepin-3-yl)methyl 2-[(tert-butoxycarbonyl)amino]-3-phenylpropanoate(ProDOT-Boc-Phe), were synthesized. Chiral poly[(3,4-dihydro-2 H-thieno[3,4-b][1,4]dioxepin-3-yl)methyl2-[(tert-butoxycarbonyl)amino]-3-phenylpropanoate](PProDOT-Boc-Phe) modified electrodes were synthesized via potentiostatic polymerization of chiral ProDOT-Boc-Phe. Chiral PProDOT-Boc-Phe films displayed good reversible redox activities. The enantioselective recognition between chiral PProDOT-Boc-Phe modified glassy carbon electrodes and DOPA enantiomers was achieved by different electrochemical technologies, including cyclic voltammetry(CV), square wave voltammetry(SWV), and differential pulse voltammetry(DPV).(D)-PProDOT-Boc-Phe and(L)-PProDOT-Boc-Phe showed higher peak current responses toward L-DOPA and DDOPA, respectively.
基金Supported by the Natural Science Foundation of Guangdong Province (No. 011563, No. 04020114).
文摘The inhibitory effect of ferulic acid on the diphenolase activity of mushroom tyrosinase and the kinetic behavior were studied with L-3,4-dihydroxyphenylalanine （L-DOPA） as substrate. The inhibitor concentration leading to 50% relative activity lost （IC50） was estimated to be 0.15 mmol·L^-1. The inhibition mechanism obtained from Lineweaver-Burk plots shows that ferulic acid is a competitive inhibitor and the inhibition of tyrosinase by ferulic acid is a reversible reaction. The equilibrium constant for ferulic acid binding with the tyrosinase was determined to be 0.25 mmol·L^-1 for diphenolase. Keywords tyrosinase, ferulic acid, kinetics, inhibition, L-DOPA, diphenolase
文摘Electroanalytic direct determination of aluminum is a difficult subject because of the highly negative reductive potential of Al(Ⅲ) and interference of H +. But developing methods for the determination of trace amount of aluminum in environmental and biological samples is a hot topic in recent decades owning to the recognition of the potential toxic effects of aluminum. In this paper, the indirect differential pulse voltammetric(DPV) determination of aluminum with L dopa(3,4 dihydroxyphenylalanine) on glass carbon working electrode has been reported. This novel method bases on the linear decrease of DPV anodic peak current of L dopa with the concentration of aluminum added. Under the optimum experimental conditions (pH 8 5, 0 08 mol/L buffer solution, 4×10 -4 mol/L L dopa), the linear range and the detection limit are (2—18)×10 -7 and 7 6×10 -8 mol/L Al(Ⅲ) respectively, the relative standard deviation for 2×10 -5 mol/L Al (Ⅲ) is 2 4%(n=10). A number of foreign species, especially those necessary components in human body such as ascorbic acid, citrate, phosphate, Fe(Ⅲ), Fe(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Ca(Ⅱ) and Mg(Ⅱ) for interference have been studied. Satisfactory recoveries have been obtained by applying this method to determining aluminum in biological samples including mineral water, synthetic renal dialysate, urine and hair. The significance of the method and solutions to possible interference encountered in in vivo detection are discussed. A new direction for further development of the in vivo determination of aluminum is provided in this studies.
基金supported by the National Natural Science Foundation of China(Grant Nos.:21976168,22127810,and 22004113)Key Research and Development Program of Guangdong Province(Grant No.:2020B1111350002)+1 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.:2019A1515110420)GDAS0 Project of Science and Technology Development(Grant No.:2021GDASYL-20210103034).
文摘A rapid and sensitive method for analyzing trace b-blockers in complex biological samples,which involved magnetic solid-phase extraction(MSPE)coupled with Fourier transform ion cyclotron resonance mass spectrometry(FTICR-MS),was developed.Novel nanosilver-functionalized magnetic nanoparticles with an interlayer of poly(3,4-dihydroxyphenylalanine)(polyDOPA@Ag-MNPs)were synthesized and used as MSPE adsorbents to extract trace b-blockers from biological samples.After extraction,the analytes loaded on the polyDOPA@Ag-MNPs were desorbed using an organic solvent and analyzed by FTICR-MS.The method was rapid and sensitive,with a total detection procedure of less than 10 min as well as limits of detection and quantification in the ranges of 3.5-6.8 pg/mL and 11.7-22.8 pg/mL,respectively.The accuracy of the method was also desirable,with recoveries ranging from 80.9%to 91.0%following the detection of analytes in human blood samples.All the experimental results demonstrated that the developed MSPE-FTICR-MS method was suitable for the rapid and sensitive analysis of trace b-blockers in complex biological samples.
