Organic Analysis Flashcards

1
Q

What are the stages in mass spectrometry?

A
Vaporisation
Ionisation
Acceleration
Deflection
Detection
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2
Q

What is the molecular ion peak?

A

The peak with the highest M/Z ratio in he spectrum

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3
Q

How can you determine the relative molecular mass using a mass spectrum?

A

Use the molecular ion peak to determine he relative molecular mass

But watch out for the (M+1) peak caused by carbon 13 isotope

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4
Q

How can we use mass spectrometry to identify different individual isomers?

A

2 isomers will have the same molecular formulas and therefore the same molecular ion peak however they produce different fragmentation patterns.

Different fragment ions will produce different peaks

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5
Q

Why can we use infrared spectroscopy (IR) to identify molecules?

A

IR radiation can be absorbed by molecules

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6
Q

How can we make an IR spectrum?

A
  1. Bean of IR radiation is passed through the sample.
  2. Molecule of our sample will absorb some of these frequencies
  3. The bean that passes through is analysed
  4. Plot a graph of transmittance against frequency ( this is the IR spectrum)
  5. Analyse the spectra that are formed
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7
Q

What is the fingerprint region of an IR spectrum?

A

Region between 500 - 1500 cm^-1

Absorption’s always e caused mainly be bending and are therefore specific to each molecule (hence fingerprint)
Tris region can be used to identify the molecule.

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8
Q

What are the applications of IR spectroscopy?

A

Breathalyser
Air quality monitor
Forensics

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9
Q

What is chromatography?

A

A separation technique for identifying chemicals in a mixture.

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10
Q

What is the stationary phase in thin layer chromatography?

A

A thin piece of unreactive material and cover it in an absorbent chemical (eg aluminium oxide)

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11
Q

What is the mobile phase in thin layer chromatography?

A

Usually and organic solvent that will move in 1 direction up the thin. Layer

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12
Q

How do you calculate the Rf value?

A

Distance moved by the compound / distance moved by the solvent.

Rf values are always between 0-1

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13
Q

What is column chromatography?

A

A Column is packed with a solid and a solvent moves down the column

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14
Q

What is gas chromatography?

A

A column is packed with a solid or with a solid coated by a liquid and a gas is passed through the column under pressure at high temperatures

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