CAJ | 학술논문

背景:以往研究多采用紫外/可见光谱、电导和电泳等方法研究金属离子与氨基酸之间的作用,但以UV-Vis光谱、荧光光谱方法研究L-组氨酸同银离子在水溶液中反应的机制少见报道.目的:采用UV-Vis光谱、荧光光谱方法研究L-组氦酸同银离子的作用机制.方法:用UV-Vis、荧光光谱法研究了组氨酸同银离子间的相互作用,考察介质的pH、Ag+离子、组氨酸、甲醉、十二烷基硫酸钠、三羟甲基氨基甲烷浓度以及光照强度和光照时间等条件对组氨酸同Ag+离子作用的影响,探究反应机制.结果与结论:pH电位滴定法测定L-组氨酸离解常数为9.21,用半(n)法求得组氨酸-Ag的逐级稳定常数为logK1=5.56,logK2=4 05,20℃时组氨酸-Ag体系的电动电位为2.10×10-4V.根据pH电位滴定法和lob法确定该配合物的组成为组氨酸:Ag=2:1.同组氨酸相比,组氨酸-Ag体系在295.3 nm有一肩峰,它对应于咪唑环产生的π-π*跃迁.而242.0 nm左右出现的吸收峰属于组氨酸中C=O的n-π*跃迁.组氨酸-Ag体系产生的荧光发射光谱归属为5D0→7F2电子偶极跃迁.同相同条件下的参比液相比,不仅发射波长蓝移,而且导致荧光猝灭.结果表明,组氨酸中的咪唑环参与了同银离子的成键作用.组氨酸同银离子发生反应后,首先生成六配位配合物,然后银离子再被甲醛还原为超细银粒而被组氨酸所包裹.
배경:이왕연구다채용자외/가견광보、전도화전영등방법연구금속리자여안기산지간적작용,단이UV-Vis광보、형광광보방법연구L-조안산동은리자재수용액중반응적궤제소견보도.목적:채용UV-Vis광보、형광광보방법연구L-조양산동은리자적작용궤제.방법:용UV-Vis、형광광보법연구료조안산동은리자간적상호작용,고찰개질적pH、Ag+리자、조안산、갑취、십이완기류산납、삼간갑기안기갑완농도이급광조강도화광조시간등조건대조안산동Ag+리자작용적영향,탐구반응궤제.결과여결론:pH전위적정법측정L-조안산리해상수위9.21,용반(n)법구득조안산-Ag적축급은정상수위logK1=5.56,logK2=4 05,20℃시조안산-Ag체계적전동전위위2.10×10-4V.근거pH전위적정법화lob법학정해배합물적조성위조안산:Ag=2:1.동조안산상비,조안산-Ag체계재295.3 nm유일견봉,타대응우미서배산생적π-π*약천.이242.0 nm좌우출현적흡수봉속우조안산중C=O적n-π*약천.조안산-Ag체계산생적형광발사광보귀속위5D0→7F2전자우겁약천.동상동조건하적삼비액상비,불부발사파장람이,이차도치형광졸멸.결과표명,조안산중적미서배삼여료동은리자적성건작용.조안산동은리자발생반응후,수선생성륙배위배합물,연후은리자재피갑철환원위초세은립이피조안산소포과.
BACKGROUND: Traditionally,UV/visible spectra,conductivity,electrophoresis and other methods are commonly applied for studying the interaction of metal ions and amino acids,but UV-Vis spectroscopy and fluorescence spectroscopy for L-histidine reacted with silver ion in aqueous solution is rarely reported.OBJECTIVE: To investigate the interaction between silver ion and histidine using UVNIS and fluorescence spectra.METHODS: The influence of pH,multicomponent concentration such as histidine,silver ion,formaldehyde,sodium dodecyl sulfate and trihydroxymethyl aminomethane,as well as illumination strength and time,on the interaction between silver ion and histidine were investigated,and the mechanism of reaction was also explored.RESULTS AND CONCLUSION: Applied pH potentiometer titration method,the dissociation constants of histidine was defined 9.21.The stepwise stability constants of histidine-silver was logK1=5.56 and logK2=4.05,respectively by using half(n)method.At 20 ℃,the electric potential of histidine-silver system was 2.10×10-4 V.According to pH potentiometer titration and lob method,the compound was consisted of histidine: Ag=2:1.Compared with histidine,histidine-silver systems reached a shoulder peak at 295.3 nm,which was assigned to conjugate double bond of imidazole ring that easily generated π-π*transition.And an absorption peak close to 242 nm can be assigned to n-π*transition of the C=O group of the histidine-silver.The fluorescence emission spectra of histidine-silver systems belonged to 5D0→7F2 electric dipole transition.Compared with reference solutions under the same conditions,it not only emitted wavelengths blue shift,but also induced fluorescence quenching.Results showed that,imidazole ring was involved in the bonding action with silver ion.The reaction process is to firstly generate six-coordination complex,secondly reduce the silver ion into ultrafine silver particles which are bound by histidine.