Spectrophotometric determination of an anionic drug using surfactant-stabilized gold nanoparticles

We report herein the development of a non-aggregation sensitive spectrophotometric method for the determination of heparin based on the electrostatic interaction between the negatively-charged heparin and the positively-charged gold nanoparticles and restabilization of nanoparticles by excessive amount of CTAB molecules. The addition of heparin on CTAB-capped gold nanoparticles (CTAB-AuNPs) induces a dramatic increase in their size which results in strong rise of extinction spectrum of CTAB-AuNPs. Since the enhanced extinction intensity at 528 nm is proportional to the concentration of heparin, quantitative determination of heparin is possible. Optimum conditions for determination of heparin including pH, concentration of CTAB-AuNPs and incubation time were investigated. Under the optimum conditions, the enhanced extinction intensity is linearly correlated with the concentration of heparin in the range of 0.0015-0.1 mM with limit of detection of 0.00067 mM. The method was successfully applied to the determination of heparin in human plasma samples

Keywords:

Heparin , Gold nanoparticles , Extinction spectrum