Catalytic formation of silver nanoparticles by bovine serum albumin protected-silver nanoclusters and its application for colorimetric detection of ascorbic acid

We established a simple spectrophotometric and colorimetric method for detection of ascorbic acid based on the growth of silver nanoparticles in bovine serum albumin protected-silver nanoclusters (BSA-AgNCs) and Ag+ mixture. Due to the catalysis of BSA-AgNCs, ascorbic acid could reduce Ag+ to silver nanoparticles (NPs) at room temperature. The color of the mixture changed from colorless to yellow and a strong absorption band near 420 nm could be found in their absorption spectra owing to localized surface plasmon resonance (LSPR) of produced silver NPs. The absorbance changes at 420 nm had a good relationship with ascorbic acid concentration. Thus, we proposed a spectrophotometric and colorimetric method to determine ascorbic acid in concentration range from 2.0 to 50.0 mu M, with the corresponding limits of determination (3 sigma) of 0.16 mu M. (C) 2013 Elsevier B.V. All rights reserved.