How to use INPUs as SERS Substrate

Reagent and apparatus : Gold nanoparticles assemble dispersion, sample solution, micropipettes, and containers such as microscope slides for blood cell monitoring or aluminum pans for thermal analyzer.

Procedure : If the gold nanoparticles assemble dispersion is phase separation, shake it mildly by gentle inversion. Put a 1 - 5 μl of the sample solution in a container with a micropipette. Add 19 - 95 μl of gold nanoparticles assemble dispersion so that total volume is 20 times of the sample. Mix by pipetting, taking care so that air bubbles do not occur.

Set the sample container to the laser Raman spectrometer so as to be focused in the sample solution slightly inside from the liquid surface. Measure at recommended low magnification. Laser power of 100 mW is also allowed in aqueous solution. Measure after 10 min aging up to the adsorption equilibrium, if necessary.

In the co-aggregation method, put the sample solution to a container, add the aggregation initiator and the gold/silver nanoparticles for SERS in this order so as to be volume ratio of 1:1:18, and mixed by pipetting. In the case of silver nanoparticles of the pre-aggregation method, the addition of chloride activation solution after mixing with the sample and silver assembles is effective.

Example

IR, Raman and SERS Spectra of Pyridine.

High-sensitive Co-aggregation SERS.

Longevity of Pre-aggregation SERS.

Days are shelf time of aggregated INPUs before use.

SERS of Various heterocyclic Rings.

Rapid Analysis of Pollen.

SERS-based Ligand-Binding Assay.

Sometimes, Glass Causes Artifact.

Contamination is Crucial. Keep Clean!

These are blank spectra of silver nanoparticles.

Fiber Raman with 785 nm(100 mW) is used.

SERS of  Benzenthiol Monolayer.

Fiber Raman with 785 nm(30 mW) is used.