Surface-enhanced Raman spectroscopy for uranium detection and analysis in environmental samples

摘要

Techniques for rapid screening of uranium in environmental samples are needed,and this study entails the development of surface-enhanced Raman scattering (SERS) for analyzing uranium in aqueous media with improved sensitivity and reproducibility.A new SERS substrate based on (aminomethyl)phosphonic acid (APA)-modified gold nanoparticles was found to give greater than three orders of magnitude SERS enhancement compared with unmodified bare gold nanoparticles.Intensities of uranyl band at about 830 cm~(-1) were proportional to the concentrations of uranium in solution,especially at relatively low concentrations (<10~(-5) M).A detection limit of ~8 x 10~(-7) M was achieved with a good reproducibility since the measurement was performed directly in dispersed aqueous suspension.Without pretreatment,the technique was successfully employed for detecting uranium in a highly contaminated groundwater with a low pH,high dissolved salts (e.g.,nitrate,sulfate,calcium and aluminum) and total organic carbon.