Determination of Mercury (II) Ion Concentrations in Human Serum Albumin Using Fluorescence Spectroscopy and Multivariate Regression Analysis

Abstract

Human serum albumin (HSA) is a protein responsible for the transportation and delivery of drug molecules, fatty acids, and metabolites to various targets and the removal of waste products from the body. However, the binding of heavy metal ions, including mercury (II) (Hg(II)), can adversely affect HSA physiological properties with deleterious health consequences. The volatility of Hg at room temperature precludes the use of conventional flame, graphite furnace, or inductively couple atomic absorption spectroscopy for routine analysis of Hg in most research and medical laboratories. This study reports the first potential utility of fluorescence spectroscopy and multivariate regression analysis for the determination of Hg(II) concentration in HSA samples. The results of Fourier transform infrared (FT-IR) spectroscopy indicated the binding of Hg(II) at HSA amide I and amide II sites. Also, the binding of Hg(II) with HSA resulted in a decreased HSA ultraviolet (UV)-visible absorption and dramatic quenching of HSA fluorescence emission. The developed multivariate partial least squares regression (PLSR) model from Hg(II)–HSA fluorescence emission data was able to predict the Hg(II) concentration in HSA samples, with a root mean square percent relative error of prediction of 6.59%. The simplicity, low cost, and robustness of this method makes it a promising alternative method for rapid determination of Hg(II) concentration in biological specimens.