Layer-by-layer Assembly Of Nanoparticles For Surface-enhanced Raman Spectroscopy Substrate And The Application In Detection Of Organic Molecules

A surface-enhanced Raman spectroscopy (SERS) active substrate was developed by using layer-by-layer assembled nanoparicles. Combined thin layer chromatography (TLC) technique with SERS for the rapid and sensitive determination of organic molecules.The high throughput, sensitive and reproducible SERS substrate was fabricated in a chip form. It was prepared by coating agarose solution on glass slide, shaping into an array pattern and drying into agarose thin film, this followed by amine-functionalization of the film surface and layer-by-layer assembly of Ag nanoparticles. After optimizing the produce parameters, the enhancement factor was as high as 1.5 x 107 for rhodamine 6G.For quantitative analysis,5 kinds of benzene derivatives and 3 kinds of amino acids were selected and tested at different concentrations. The results suggested quantitative detection of organic small molecules can be achieved on this SERS substrate. Benefits from the array pattern on the substrate, variety of samples can be determined on one chip, such as biomolecules and environmental pollutants.Silver colloid was applied on thin layer chromatography (TLC) plate for SERS analysis of aromatic amines compounds. Several experimental conditions were studied to optimize the detection, including the concentration of Ag colloid and concentration of aggregating agents. After optimization, qualitative detection of p-aminophenol, p-nitroaniline, aniline and benzidine were achieved with the limit of detection in ppb level. Real water samples were also tested, and the results showed the interference of organisms in water is negligible. This method is capable of on-site and rapid analysis of metabolic aromatic amines pollutants.