以黄连素为荧光探针测定配合物的平衡常数

Determination of the Equilibrium Constant of the Complexes Using Berberine as a Fluorescent Probe

以黄连素(BER)为荧光探针,研究了碱金属离子、铵离子和黄连素在葫芦脲[7]中的包合竞争反应.发现葫芦脲[7]与黄连素在一定的条件下能生成稳定的CB[7]-BER荧光探针体系,且具有强的荧光发射.然而分别将碱金属离子,铵离子加到CB[7]-BER包合物体系中时,荧光强度呈现有规律的下降,且荧光猝灭值ΔF与阳离子的浓度呈良好的线性关系,以此为基础,研究了碱金属离子和葫芦脲[7]相互作用的平衡常数,发现对于同一主族元素,随着原子半径的增大,与葫芦脲[7]形成配合物的平衡常数也依次增大、銨离子与葫芦脲[7]形成的平衡常数介于钠离子和钾离子之间。

Using BER as the Fluorecence probe,the Alkali metals ion and Berberine in the inclusion competition reaction with cucurbit[7]uril is studied,it is found that under certain conditions,cucurbit[7]uril can react with berberine to form stable CB[7]-BER Fluorecence probe system,and show intense fluorescence emissions.However,when we add Alkali metals ion and ammonium ion to the cucurbit[7]uril/Berberine inclusion system,the fluorescence intensity is becoming weak regularly,and the fluorescence quenching values（ΔF） show good linear relationship with cation ions’concentration.Based on this,we study the equilibrium constant of Alkali metals and cucurbit[7]uril and find that for the elements in the same maingroup,with the increase of atomic radius,the equilibrium constant with cucurbit[7]uril complex formation in turn increases,the equilibrium constant of ammonium ion with cucurbit[7]uril is between the sodium and potassium ions.