W5 Biomedical Applications of Infrared and Raman Flashcards
how are IR and Raman methods complementary
water is a problem in IR but not in Raman
data acquisition is slow in Raman but fast in IR
some bands are strong in IR but weak in Raman and vice versa
what is the second derivative of IR spectrum
bands in original IR can be broad and overlapping
second derivative os spectra calculated > every maximum in original spectrum becomes a minimum > produce much sharper bands that can be easily quantified in intensity and wavenumber
has very very sharp bands and a flat baseline
if given a spectrum, how to tell whether its IR or Raman
if IR: y axis is absorbance
if Raman: y axis is intensity
what is the most sensitive IR band to secondary structure
amide I
what is the most useful IR region for biologists
mid IR
in raman, what is the incident light and what is the emitted light
red or nIR
what is surface enhanced Raman spectroscopy (SERS)
method to solve issue of raman radiation being very weak and thus require long data collections
uses metallic nanostructure to increase intensity of raman scattering signals
enhancement is through resonance between excitation laser and raman scattering with localised surface plasmons (clouds of electrons) in the metallic nanostructure
what is the wavelength of beta structure band
1635cm-1
what is usually used for identification of microorganisms
vibrational spectroscopies as different species have different compositions of lipids and proteins > different vibrational spectra
why is IR better than hematoxylin and eosin
can be used to represent abundance in nucleic acids, proteins or lipids just by selecting different band absorbances in the spectra of the pixels
what is the use of raman micro spectroscopy
raman radiation is very weak and requires high energy laser beam for excitation
by focussing a laser beam on a very small volume > only that small volume emit significant of raman photons
can scan small volumes in sample and collect raman spectra of each volume
