Raman Spectroscopy
Our Raman projects focus on development and applications of a Reflective Raman Substrate (RRS) which is fabricated with proper surface modifications. It only requires a small drop of sample, but the signal output will be amplified due to high reflectivity of the substrate, which enhances the sensitivity tremendously. Therefore, the spectral acquisition will be more efficient and the results can be highly reliable.
Drop Coating Deposition Raman (DCDR) for Protein Analysis
Procedure
•Deposit a small drop (10 mL) of protein solution on RS2 and allow it to dry
•Take Raman spectrum by focusing laser on the ring formed by the dried protein
Advantages
•Ultrasmall sample consumption—sub nanomole of protein are adequate
•Drastically enhanced spectral signal-to-noise ratio.
•Individually addressed sampling spots for convenient bookkeeping.
Sequential Drop Coating Deposition Raman (DCDR) and Surface Enhanced Raman (SERS) on RRS
Procedure
•Add 10 mL 1 mM sample solution onto a RRS slide and allow it to dry in a dust-free chamber.
•Take the DCDR spectrum of the sample by focusing laser on the dried powder
•add 10 mL gold nanoparticle solution on the DCDR sampled spot and mix with the pipette tip.
•Acquire SERS spectra by focusing laser on gold-nanoparticle-treated sample spot.
Advantages
•Exceedingly facile preparation by simply drop-drying and mixing.
•Highly efficient spectral acquisition: entire normal Raman and SERS are completed within 10 mins.
•Ultrasmall sample consumption: The same miniscule (nmol) amount of sample is used for both normal Raman and SERS analysis.
Enhanced capability for resolving complex mixtures with combined selectivity from both DCDR and SERS
Raman Crystallography on RRS Slide with Sitting Drop Vapor Diffusion Method
Procedure
•Deposit one drop of concentrated sample solution on RS2 slide
•Allow solvent to evaporate in an closed chamber containing reservoir solution prepared with saturated electrolytes.
•Take Raman spectra for the crystals formed by analytes in the sample solution
Advantages
•Miniscule sample consumption
•Rapid crystallographic screening through both optical imaging and Raman spectral acquisition