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Index
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QUALITY CONTROL 2 LEC
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INFRARED
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Level 3
level: Level 3
Questions and Answers List
level questions: Level 3
Question
Answer
IR Instruments: FOR QUALITATIVE IDENTIFICATION
1 Dispersive spectrometers 2 Fourier-transform (FTIR)
uses MONOCHROMATOR to select each wavenumber to MONITOR INTENSITY after passing thru sample
Dispersive spectrometers
uses INTERFEROMETER - generates radiation WITHOUT dispersion, faster, xtract the spectrum from a series of overlapping frequencies.
Fourier-transform (FTIR)
IR Instruments: FOR QUANTITATIVE IDENTIFICATION
1. Filter photometer
THEORY In order for IR radiation to be absorbed by a molecule: 1. Molecule should possess a __ frequency identical to that of impinging EM radiation
vibrational or rotational
Types of Molecular vibrations:
1 Stretching 2 Bending (deformation)
1 distance increase or decreases along BOND AXIS 2 in which BOND ANGLES occurs
1 Stretching 2 Bending (deformation)
1 in plane stretching movements 2 in plane bending movements 3 out of plane bending movements
1 Asymmetric, Symmetric 2 Scissoring, Rocking 3 twisting, wagging
Application of IR spectrophotometry in STRUCTURE ELUCIDATION 1 Pharmaceutical analysis it is a __ technique 2 The most readily assigned absorptions are usually at
. 1 fingerprint 2) > 1500 cm-1