Spectroscopy Flashcards

1
Q

What is nmr spectroscopy

A

Interaction of low energy radio waves and nuclei within a strong magnetic field

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2
Q

Types of nmr

A

Carbon 13
H (proton)

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3
Q

Carbon 13 nmr

A

Peak for every different carbon environment ( equivalent c atom)

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4
Q

H nmr

A

A peak for each set of hydrogen environments

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5
Q

Integration ratio

A

Each signal is proportional to the number of equivalent H atoms

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6
Q

Spin spin coupling

A

High resolution h nmr each signal can be split into further lines depending on neighbouring carbon atoms

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7
Q

Splitting of peak

A

Number of inequivalent Hs on neighbouring c atoms + 1

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8
Q

NMR solvents

A

CDCl3
D2O identify oh and amide

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9
Q

Calibration compound

A

Tetramethylsilane added to calibrate the spectrum
1 NMR peak at 0
Inert and volatile doesn’t react

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10
Q

Why is TMS used

A

Signal is away from all the others
Only gives one strong signal
Non toxic
Inert
Low bo so can be removed easily

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11
Q

Electronegativity effect on nmr

A

The more electronegative an atom bonded to a carbon the greater the ppm

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12
Q

What is chromatography

A

Analytical tech that separates components in a mixture between a mobile phase and stationary phase

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13
Q

How does a solid stationary phase separate

A

Adsorption

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14
Q

How does liquid stationary phase separate

A

Relative solubility

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15
Q

TLC paper

A

Contains silica which is very polar

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16
Q

If stationary phase was polar and mobile stage was non polar what would happen to the compounds

A

If compounds were non polar they would pass through the column quicker than the polar molecules as non polar molecules are more soluble in the mobile phase

17
Q

Gas liquid chromatography

A

Used to separate mixtures of volatile liquids due to different adsorption and attraction to the different phases

18
Q

Retention time

A

The time taken for compound to travel from injection to where it leaves the column to the detector

19
Q

Slower the retention time

A

Greater attraction to the stationary phase more adsorption therefore takes longer to travel out of the column