Spectrofluorimetric determination of human serum albumin using a tetracycline-europium complex

A new spectrofluorimetrie method is proposed for determination of human serum albumin (HSA). Using tetracycline (TC)-europium (Eu3+) as a fluorescent complex, in the buffer solution of pH = 10.2, HSA can remarkably enhance the fluorescence intensity of the TC-Eu3+ complex at lambda= 612 nm and the enhanced fluorescence intensity of Eu3+ ion iS in proportion to the concentration of HSA. Optimum conditions for the determination of HSA were also investigated. The linear ranges for HSA are 0-2.5 x 10(-5) mol L-1 and 2.5 x 10(-5) -2.0 x 10(-4) mol L-1 with limits of detection are 2.4 x 10(-6) mol L-1 and 1.5 x 10(-5) mol L-1, respectively. This method is simple, practical, and relatively free interference from coexisting substances and can be successfully applied to determination of HSA in samples of serum and urine.