Fluorospectrophotometric Determination of SudanⅠ by Its Fluorescence Quenching Effect on Human Serum Albumin

The fluorescence characteristics of human serum albumin (HSA) and the fluorescence quenching by the presence of SudanⅠ were studied in 0.1 mol·L-1 Tris-HCl buffer medium of pH 8.2.It was found that emission fluorescence was observed at 337 nm (λem) when the HSA solution was excited at 290 nm (λex),and that the intensity of the emitted fluorescence was quenched by the addition of SudanⅠ solution.Linear relationship was kept between the magnitude of decrease in fluorescence intensity (ΔF) and the concentration of SudanⅠ in the range of 0.5-7.5 mg·L-1 (r=0.999 7).Detection limit (3Sb/k) and determination limit (10Sb/k) were found to be 0.1 mg·L-1 and 0.5 mg·L-1 respectively.Tests for precision and recovery at different concentration levels were made,giving values of RSD′s (m=6,n=11) and of recovery were found in ranges of 0.7%-1.8% and 91.9%-109.3% respectively..