Spectrophotometric determination of urinary protein with o-sulfophenylfluorone-metal complex

Takako Yamaguchi, Emi Amano, Shinichiro Kamino, Satoko Umehara, Chizuko Yanaihara, Yoshikazu Fujita

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12 Citations (Scopus)


A simple and sensitive spectrophotometric method for the determination of human serum albumin (HSA) was established based on the ternary complex-formation reaction of HSA with o-sulfophenylfluorone (SPF) as a xanthene dye and metal ion (niobium(V) and bismuth(III)) in the presence of a dispersion agent. This new method enabled the determination of HSA in the range of 1-15 μg/ml HSA by measuring the difference of the absorbance at 530 nm between HSA-SPF-metal ion and SPF-metal ion solutions. In the determination of HSA, this method is about 2-times more sensitive than the Pyrogallol Red-molybdenum(VI) method (PR method), which accounts for more than 80% of the quantification methods for urinary protein assays in Japan. There was no significant difference between the results obtained by the present method and the PR method for human urine samples. The binding process between the SPF-metal complex and HSA was studied by determining the binding parameters and the thermodynamic parameters.

Original languageEnglish
Pages (from-to)1237-1240
Number of pages4
JournalAnalytical Sciences
Issue number10
Publication statusPublished - Oct 2005
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry


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