Researchers from Spain have investigated surface enhanced Raman scattering (SERS) as a potential tool for the simultaneous detection of two metal pollutants, Co(II) and Cu(II), at ultratrace levels.
The authors functionalized silver nanoparticles with a metal ion receptor molecule, terpyridine (TPY), which is known to bind to first-row transition metal ions with high affinity. Dithiocarbamate (DTC) is introduced to the TPY structure in order to facilitate adsorption onto the nanoparticle surface. Upon addition of metal ions, such as Co(II) and Cu(II), a conformational change takes place, which can be detected as a peak shift in the Raman spectra. This shift is unique to the ion that is conjugated to the TPY-DTC ligand, allowing the simultaneous detection of both Co(II) and Cu(II) ions, which are known to cause teratogenic or carcinogenic effects when bioaccumulated to high concentrations.
The authors demonstrate a limit of detection of 6.5 ppb and 60 ppt for Cu(II) and Co(II), respectively. This sensitivity is significantly higher when compared to analogous techniques, such as AAS or AES, demonstrating the applicability of SERS as tool for the sensitive detection of metal ions.
by Dr Lee Barrett
Full details can be found in the Nanoscale article:
Simultaneous SERS detection of copper and cobalt at ultratrace levels
Dionysia Tsoutsi, Luca Guerrini, Jose Manuel Hermida-Ramon, Vincenzo Giannini, Luis M. Liz-Marzán, Alex Wei and Ramon A Alvarez-Puebla