Fluorescence Titration of Loosely Bound Extracellular Polymeric Substances with Cu (II) from Hongfeng Lake Sediment

Abstract:

In order to understand the micro-interfacial relationship between environmental copper ions and loosely bound extracellular polymeric substances (LB-EPS), a fluorescence titration of LB-EPS from the Hongfeng lake sediment by Cu (Ⅱ) was studied. Results showed that Cu (Ⅱ) could debase the fluorescence intensity (FI) of LB-EPS. Titration of LB-EPS by Cu (Ⅱ) at pH values of 4.0, 6.0, 7.0 and 9.0 demonstrated an obvious variety of wavelength spectra. The FI of LB-EPS reacting with Cu (Ⅱ) (2.5×10-4M), with the increase of pH values, decreased, which was attributed to more conjunct capacity of the fluorophore with Cu (Ⅱ) in alkaline conditions. At low or middle pH, the quenching of LB-EPS by Cu (Ⅱ) was attributed to the complex quenching triggered by ligand processes; and in the high pH the cause of quenching was not only linked to complex quenching, but also related to collision quenching.

• Periodical: Advanced Materials Research (Volumes 610-613)
• Pages: 280-283
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.610-613.280
• Online since: December 2012
• Authors: Juan Li, Jian Long, Fu Xing Kang
• Keywords: Cu(II), Fluorescence Titration, LB-EPS, Protein

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