Ratiometric colorimetric determination of coenzyme A using gold nanoparticles and a binuclear uranyl complex as optical probes

• Published in: Mikrochimica acta (1966) 2016-02, Vol.183 (2), p.715-721
• Main Authors: Wu, Rurong, Liao, Lifu, Li, Shijun, Yang, Yanyan, Xiao, Xilin, Nie, Changming
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chelation; Chemistry; Chemistry and Materials Science; Colorimetry; Enzymes; Gold; Investigations; Liver; Microengineering; Nanochemistry; Nanoparticles; Nanotechnology; Original Paper; Phosphates; Thiols
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-015-1716-0

We describe a ratiometric colorimetric method for the determination of coenzyme A (CoA) by using gold nanoparticles (AuNPs) and bis-uranyl-bis-sulfosalophen (BUBSS) as optical probes. BUBSS is a binuclear uranyl complex and formed through the chelating reaction of two uranyl ions with bis-sulfosalophen. CoA is captured by the AuNPs via the thiol group and this leads to the formation of CoA-AuNPs. In a second step, BUBSS binds two CoA-AuNPs through a coordination reaction between the uranyl ions in BUBSS and the phosphate groups in CoA-AuNPs. This causes the CoA-AuNPs to aggregate and results in a color change from wine red to blue. A ratiometric colorimetric assay was established for CoA based on the ratiometric measurement of absorbance changes at 650 and 525 nm. Their ratio is linearly related to the concentration of CoA in the 0 to 1.2 μmol⋅L -1 range, with a 6 nmol⋅L -1 detection limit under optimal conditions. The method was successfully applied to the determination of CoA in spiked liver samples with recoveries between 99.4 and 102.6 %. Graphical Abstract Gold nanoparticles (AuNPs) capture Coenzyme A (CoA) firstly and then bind bis-uranyl-bis-sulfosalophen (BUBSS). This causes their aggregation and results in a color change. A ratiometric colorimetric assay was established for CoA based on measuring absorbances at 630 and 525 nm.