1. Highly sensitive spectrofluorimetric determination of cysteine by Cu2+-morin complex.
- Author
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Wen-Sheng Liao, Fang-Ying Wu, Yu-Mei Wu, and Xiao-Jiao Wang
- Subjects
FLUORESCENCE ,MICROBIOLOGICAL assay ,CYSTEINE proteinase inhibitors ,TESTING laboratories ,OXIDATION-reduction reaction ,BUFFER solutions ,URINE microbiology ,PORCINE somatotropin - Abstract
A simple and sensitive fluorescence enhancement assay of trace cysteine (Cys) is presented. The method is based on the redox reaction between the Cu
2+ -morin complex and Cys. In Britton-Robinson buffer of pH 7.4, the addition of Cys to the Cu2+ -morin system results in dramatic fluorescence intensity increase at 539 nm which is proportional to the concentration of Cys over the range of 6.52 × 10−7 –2.20 × 10−5 mol L−1 , with a limit of detection of 6.52 × 10−8 mol L−1 . The method was applied to determine Cys in protein hydrolysate of fresh porcine blood and human urine, the recoveries being 91.3–94.1% and 95–98.6% respectively. The mechanism involved in the reaction was also studied. [ABSTRACT FROM AUTHOR]- Published
- 2008
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