Study of the binding equilibrium between Zn(II) and HSA by capillary electrophoresis-inductively coupled plasma optical emission spectrometry

A new method has been developed for following the interaction between zinc ion and human serum albumin (HSA) by capillary electrophoresis-inductively coupled plasma optical emission spectrometry. Under optimized experimental conditions, the detection limit (3σ) for free Zn(2+) ion was found to be 1.34 μM by running 11 replicates of the reagent blank. The RSD was less than 3% and the recovery was more than 98.13%. The linear range of zinc ion concentration was between 5.1 μM and 0.3M. The measured Zn(II)-HSA combination values of n(1) and K(1) for primary binding of Zn(2+) to HSA were 1.09 and 2.29×10(5) L mol(-1), respectively. The measured values of n(2) and K(2) for the non-specific binding of Zn(2+) to HSA were 8.96 and 6.65×10(3) L mol(-1), respectively. This new method allows rapid analysis of a small amount of sample, simple operation, while avoiding long periods of dialysis and eliminating interference from other metal ions. This method provides a reliable and convenient new way for studying interactions between metal ions and biomolecules.