biochemical spectroscopy

Question 1

Define Qualitative techniques ?

what is present ?

Answer 1

Microscopy,chromotography,simple color tests
-mass spectrometry and in IR spectroscopy

Question 2

Define Quantitative techniques ?

how much is present

Answer 2

HPLC (high performance liquis chromatography)
-UV-vis,NMR

Question 3

What does spectroscopy imply?

Answer 3

implies interactions of substances with radiaition

Question 4

What can light be thought of as ?

Answer 4

waves of electromagnetic radiation
-wavelength λ
-frequency ν
-speed c
-amplitude

Question 5

What is the relationship between v and λ ?

Answer 5

c = vλ

Question 6

The electromagnetic spectrum and its order ?

Answer 6

RED TO BLUE
10^3-10^-11
radio frequency Raw
microwaves Meat
infrared Is
visable Very
ultra-violet Unsanitary
x-rays eXcept
gamma rays Giraffe

Question 7

What is a use of EM radiation in life sciences ?

Answer 7

1.)Gamma rays
originate from nucleur decays
-used in diagnostic nuclear medicine
eg.) technetium-99m
2.) X-rays
produced by high-energy electronic transitions in atoms
used for x-ray imaging
x-ray diffraction
3.)UV/visable
absorbed by many biomolecules
these energies correspond to electronic transitions between molecular orbitals

Question 8

What is IR spectroscopy ?

Answer 8

same principle as UV/vis
-shine light on sample
-measure absorbance at diff energies
-these can be described as diff wavelengths

Question 9

How does IR light interact with molecules ?

Answer 9

diff from UV
IR energies correspond to molecular vibrations

Question 10

What are the energies of molecular vibrations ?

Answer 10

these motions lie between 10-50 kJ mol
IR spectra typically cover wavelength from 2.5-20 micrometer
IR spectroscopists do not refer to λ but to 1/λ

Question 11

What is the % transmittance of IR spectra ?

Answer 11

I/I0 X100

Question 12

How to interpret IR spectrums/

Answer 12

large scale “soggy” vibrations appear below 1500 cm-1
-complicated finger print
-hard to interpret
Localised vibrations appear between 4000 cm &1500
-usefull for identifying functional group
-streching vibrations are particularly useful diagnosticly

Question 13

hint to position of stretches ?

Answer 13

single bonds- to hydrogen are high frequency becuase hydrogen is so small
When atoms are roughly same size,
triple bonds stretch at a higher frequency than double

Question 14

What is pulse oximetry ?

Answer 14

non invasive technique to measure blood oxygen levels
% hemoglobin bound to oxygen
uses spectroscopic features if haemoglobin to calculate oxygen level
measures absorbance at 2 wavelengths
-660nm red,visable
-940nm near IR