Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 43: Plasmonics and Nanooptics IV
O 43.3: Vortrag
Mittwoch, 13. März 2013, 11:00–11:15, H31
Detecting low concentrations of pollutant chemicals in water by SERS:Combining optimised nanoparticle ensembles and SERDS — •Robert Ossig1, Yong-Hyok Kwon2, Heinz-Detlef Kronfeldt2, and Frank Hubenthal1 — 1Institut für Physik and CINSaT, Universität Kassel, Germany — 2Technische Universität Berlin, Institut für Optik und Atomare Physik, Germany
We present a sensor that is suitable to detect very low concentrations of pollutant chemicals, e.g. polycyclic aromatic hydrocarbons (PAHs). To meet the European Quality Standard (EQS) criteria for PAHs, which require limits of detection (LOD) in the sub nMol/l regime, we combined surface enhanced Raman spectroscopy (SERS) with shifted excitation Raman difference spectroscopy (SERDS) and used supported noble metal nanoparticles (NPs) as SERS substrates. The NPs were prepared by Volmer-Weber growth under ultra high vacuum conditions. To gain optimal SERS enhancement the NPs plasmon resonance positions were tuned to coincide with the excitation wavelengths for SERDS. We demonstrate that our sensor using bare NPs yield LODs between 2 and 4 nMol/l, sufficient to detect the maximum allowable concentration of PAHs in water, as determined by the EQS. Furthermore we can reliably detect these concentrations in about 10 minutes. However, the annual average concentration requires LODs below the nMol/l regime. To reliably detect such low concentrations the functionalization of the NPs is currently under investigation. The functionalization enhances the adsorption of probe molecules to the NPs, which leads to a further improvement of the LOD.