Microfluidic setup for on-line SERS monitoring using laser induced nanoparticle spots as SERS active substrate.

Oana-M Buja,Nicolae Leopold,Jörg Nestler,Andreas Morschhauser,Ovidiu D Gordan,Dietrich R T Zahn

doi:10.3762/bjnano.8.26

Abstract

A microfluidic setup which enables on-line monitoring of residues of malachite green (MG) using surface-enhanced Raman scattering (SERS) is reported. The SERS active substrate was prepared via laser induced synthesis of silver or gold nanoparticles spot on the bottom of a 200 μm inner dimension glass capillary, by focusing the laser beam during a continuous flow of a mixture of silver nitrate or gold chloride and sodium citrate. The described microfluidic setup enables within a few minutes the monitoring of several processes: the synthesis of the SERS active spot, MG adsorption to the metal surface, detection of the analyte when saturation of the SERS signal is reached, and finally, the desorption of MG from the spot. Moreover, after MG complete desorption, the regeneration of the SERS active spot was achieved. The detection of MG was possible down to 10−7 M concentration with a good reproducibility when using silver or gold spots as SERS substrate.

Highlights

Over the past decade special attention has been given to the investigation of hazardous environmental chemicals with impact on human health [1,2,3,4]
The described microfluidic setup enables within a few minutes the monitoring of several processes: the synthesis of the surface-enhanced Raman scattering (SERS) active spot, malachite green (MG) adsorption to the metal surface, detection of the analyte when saturation of the SERS signal is reached, and the desorption of MG from the spot
We reported a straightforward approach for on-line preparation of silver and gold nanoparticle spots as SERS active substrates, which was used for fast detection of the model compound MG

Summary

Introduction

Over the past decade special attention has been given to the investigation of hazardous environmental chemicals with impact on human health [1,2,3,4]. The SERS active substrate was prepared via laser induced synthesis of silver or gold nanoparticles spot on the bottom of a 200 μm inner dimension glass capillary, by focusing the laser beam during a continuous flow of a mixture of silver nitrate or gold chloride and sodium citrate.

Results

Conclusion