Assessment of silver and gold substrates for the detection of amphetamine sulfate by surface enhanced Raman scattering (SERS)

Abstract

Methods of detection of amphetamine sulfate using surface enhanced Raman scattering (SERS) from colloidal suspensions and vapour deposited films of both silver and gold are compared. Different aggregating agents are required to produce effective SERS from silver and gold colloidal suspensions. Gold colloid and vapour deposited gold films give weaker scattering than the equivalent silver substrates when high concentrations of drug are analysed but they also give lower detection limits, suggesting a smaller surface enhancement but stronger surface adsorption. A 10(-5) mol dm(-3) solution (the final concentration after addition of colloid was 10(-6) mol dm(-3)) of amphetamine sulfate was detected from gold colloid with an RSD of 5.4%. 25 microl of the same solution could be detected on a roughened gold film. The intensities of the spectra varied across the film surface resulting in relatively high RSDs. The precision was improved by averaging the scattering from several points on the surface. An attempt to improve the detection limit and precision by concentrating a suspension of gold colloid and amphetamine sulfate in aluminium wells did not give effective quantitation. Thus, positive identification and semi-quantitative estimation of amphetamine sulfate can be made quickly and easily using SERS from suspended gold colloid with the appropriate aggregating agents.

Electrochemical and spectroscopic characterisation of amphetamine-like drugs: Application to the screening of 3,4-methylenedioxymethamphetamine (MDMA) and its synthetic precursors

“…Raman spectroscopy has lately been shown to be a valuable tool for an unambiguous detection of amphetamine-like products [14,17]. Actually, this technique provides a spectral fingerprint of the compounds tested and can thus be used to identify even chemically similar intermediates, as well as to trace back the precursor materials and the synthetic pathways employed in the preparation of the samples.…”

“…Although there are some reported studies on the Raman analysis of amphetamine-like compounds [14][15][16][17][18][19][20][21], these experiments have only focused on particular regions of the vibrational spectra.…”

Surface-Enhanced Raman Scattering (SERS) and Surface-Enhanced Resonance Raman Scattering (SERRS): A Review of Applications

“…There are a very wide range of possible SERS applications including its use to identify many analytes such as DNA bases, 47 explosives, 48 therapeutic agents, 49 drugs of abuse, 50 food additives, 51 and cells and spores. 52 As examples, three applications illustrating the potential of the technique are highlighted.…”

Gold nanoparticles explore cells: Cellular uptake and their use as intracellular probes

“…The SERS spectrum is a vibrational 'fingerprint' which characterises the chemical bonds and symmetry of the molecule. [4] Recently, nanoparticle-based SERS has been employed in many biomedical applications from chemical sensing [11][12][13] to cancer detection in body fluids and tissues [14][15][16][17].…”