Rhodamine B can react with bovine serum albumin to produce an electrochemically non-active supermolecular Rhodamine B BSA in the buffer solution of （CH2）6 N4 （pH 5.0）. Rhodamine B has welldefined second order derivative linear-sweep polarographic wave at 0. 87 V（vs. SCE）. Adding BSA into the Rhodamine B solution resulted in the decrease of the peak current but not change of peak potential. The decrease of the peak current is proportional to BSA concentration from 2. 5 to 30 mg/L, the limit of the detection is 1.3 mg/L, and the correlation coefficient is 0....
