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infrared spectroscopy
the study of the reflected, absorbed, or transmitted radiant energy in that region of the electromagnetic spectrum from wavelength 0.8 to 500um
frequency
the number of waves per unit length
polymorphism
change in the crystaline structure due to grinding
Which cateegory of drugs does polymorphism primarily affect?
barbiturates
What molecular interactions are the bases for infrared spectroscopy?
dipole moments
ATR stands for
attenuated total reflection
FT in FTIR stands for
fourier transform
Why is potassium bromide (KBr) used in the IR analysis of drugs?
KBr does not absorb within in the mid-IR region
IR absorption only occurs where a change of the ________ ________ of the molecule can take place.
dipole moment
What is evanescent?
A series of reflective absorptive interactions; multiple internal reflections
Name 3 sample preparation techniques that can be used for liquid and solid samples.
on KBr disk or "neat"
ATR
liquid film
Name the 3 regions within the IR spectrum.
Near infared
Mid-infared
Far-infared
Which region within the IR spectrum is used in the IR analysis of drugs?
Mid-infared
Name the 2 sub-regions within the mid-infared region.
Group frequency region
Fingerprint region
___________ bands are the primary absorption bands for each mode of vibration.
Fundamental
____________ bands occur at multiples of the fundamental bands.
Overtone
___________ bands occur at wavelengths that are the sum or difference of 2 or more fundamental bands.
Combination
_____________ bands are the strongest of the 3.
Fundamental
Give the formula for calculating wavenumber (v) from the wavelength.
Wavenumber(v) = 10
4
/ Wavelength
In what units are wavenumber (v) and wavelength expressed?
v = cm
-1
or reciprocal centimeters
Wavelength = u (microns)
What are 2 reasons you might use KCl instead of KBr for IR sample preparation?
KCl is less hygroscopic
chemical changes
What is the major difference between a dispersive IR and an FTIR ( with an interferometer)?
monochromator vs interferometer
True or False
Diatomic molecules (such as H
2
, N
2,
& O
2
) do not absorb in the infrared region.
True
False
True
True or False
IR cannot be used to distinguish between diastereomers.
True
False
False
it can be used
True or False
For forensic drug analysis, the IR region that is typically scanned is from 4000 - 400cm
-1
.
True
False
True
True or False
IR is a highly characteristic property that can be used for identity and structural elucidation.
True
False
True
True or False
IR spectra can only be obtained from liquid and solid samples.
True
False
False
can be obtained from liquid, solid, & gas
Name the 5 parts of the interferometer.
Source
Moveable mirror
Fixed mirror
Beam splitter
Detector
Author
abbyljones9
ID
137076
Card Set
IR
Description
Drug Analysis
Updated
2012-02-27T01:48:46Z
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