Analytical Instruments Methods

[H2O]

What do the following involve & what are the differences & what do they analyze:
-NMR
-UV-Vis
-AAS
-AES
-IR

[soccerboi]

NMR: Qualitative,Structure of organic molecules, tells us chemical environments(H and C). Radio waves cause spinning nucleons to flip.

UV -Vis: Qualitative and Quantitative, conc of colourless compounds, wavelength absorbed used to determine conc.

AAS: Qualitative and Quantitative, conc of metals and metal ions, e- in vaporised metal atom moves from ground state to excited then back again.

AES: Similar to AAS but emission of light is observed instead of absorption.

IR: Qualitative,types of bonding and functional groups, IR radiation causes change in bond vibrational modes and cause stretching and bending of intramolecular bonds.

Mass spec: Qualitative, gives info about molar mass, types of isotopes and relative abundance and how compounds fragment.
Stages: vaporisation,ionisation,acceleration, deflection,detection.

[charmanderp]

UV-Vis isn't qualitative.

[nisha]

NMR: Qualitative,Structure of organic molecules, tells us chemical environments(H and C). Radio waves cause spinning nucleons to flip.

UV -Vis: Qualitative and Quantitative, conc of colourless compounds, wavelength absorbed used to determine conc.

AAS: Qualitative and Quantitative, conc of metals and metal ions, e- in vaporised metal atom moves from ground state to excited then back again.

AES: Similar to AAS but emission of light is observed instead of absorption.

IR: Qualitative,types of bonding and functional groups, IR radiation causes change in bond vibrational modes and cause stretching and bending of intramolecular bonds.

Mass spec: Qualitative, gives info about molar mass, types of isotopes and relative abundance and how compounds fragment.
Stages: vaporisation,ionisation,acceleration, deflection,detection.

Pretty sure AAS is just Quantitative, as you have to pick the Hollow Cathode Lamp specifically for that particular metal, as it is specific for the wavelengths that each absorb.

[Bhootnike]

NMR: Qualitative,Structure of organic molecules, tells us chemical environments(H and C). Radio waves cause spinning nucleons to flip.

UV -Vis: Qualitative and Quantitative, conc of colourless compounds, wavelength absorbed used to determine conc.

AAS: Qualitative and Quantitative, conc of metals and metal ions, e- in vaporised metal atom moves from ground state to excited then back again.

AES: Similar to AAS but emission of light is observed instead of absorption.

IR: Qualitative,types of bonding and functional groups, IR radiation causes change in bond vibrational modes and cause stretching and bending of intramolecular bonds.

Mass spec: Qualitative, gives info about molar mass, types of isotopes and relative abundance and how compounds fragment.
Stages: vaporisation,ionisation,acceleration, deflection,detection.

Pretty sure AAS is just Quantitative, as you have to pick the Hollow Cathode Lamp specifically for that particular metal, as it is specific for the wavelengths that each absorb.

it can be used to detect the presence of a metal i thought. like if i chucked some 'unknown' chemical into the AAS, and used a sodium lamp, to see if there is any sodium in it, if i get absorbances that would  mean the sodium is in the chemical, wouldnt it?

[ggxoxo]

UV-Vis isn't qualitative.

UV-Vis can be qualitative- diff bonds have their own characteristic absorption  bonds- can compare this with known substances

[charmanderp]

NMR: Qualitative,Structure of organic molecules, tells us chemical environments(H and C). Radio waves cause spinning nucleons to flip.

UV -Vis: Qualitative and Quantitative, conc of colourless compounds, wavelength absorbed used to determine conc.

AAS: Qualitative and Quantitative, conc of metals and metal ions, e- in vaporised metal atom moves from ground state to excited then back again.

AES: Similar to AAS but emission of light is observed instead of absorption.

IR: Qualitative,types of bonding and functional groups, IR radiation causes change in bond vibrational modes and cause stretching and bending of intramolecular bonds.

Mass spec: Qualitative, gives info about molar mass, types of isotopes and relative abundance and how compounds fragment.
Stages: vaporisation,ionisation,acceleration, deflection,detection.

Pretty sure AAS is just Quantitative, as you have to pick the Hollow Cathode Lamp specifically for that particular metal, as it is specific for the wavelengths that each absorb.

it can be used to detect the presence of a metal i thought. like if i chucked some 'unknown' chemical into the AAS, and used a sodium lamp, to see if there is any sodium in it, if i get absorbances that would  mean the sodium is in the chemical, wouldnt it?

This is true.

[oneoneoneone]

UV-Vis isn't qualitative.

UV-Vis can be qualitative- diff bonds have their own characteristic absorption  bonds- can compare this with known substances

Aren't bonds associated with IR Spec?

[charmanderp]

UV-Vis isn't qualitative.

UV-Vis can be qualitative- diff bonds have their own characteristic absorption  bonds- can compare this with known substances

With UV-Vis we're often analysing mixtures of compounds and hence we can't even accurately run quanitative analysis unless we know what's in it.

We CAN use it for qualitative analysis of organic substances but it's pretty arduous and not in the course AFAIK. I doubt they'll ask you such a question but I'd compare it to saying NMR, IR or Mass Spec is quantitative, which it can be but not without quite some work and not too reliably.

[charmanderp]

UV-Vis isn't qualitative.

UV-Vis can be qualitative- diff bonds have their own characteristic absorption  bonds- can compare this with known substances

Aren't bonds associated with IR Spec?

It applies somewhat to UV-Vis too. This is absorption of a different kind of energy.

[H2O]

AAS: Qualitative and Quantitative, conc of metals and metal ions, e- in vaporised metal atom moves from ground state to excited then back again.

AES: Similar to AAS but emission of light is observed instead of absorption.

About these two,
Which release and absorb energy?
By the way, isn't AAS from excited --> ground state?  :S

[Tonychet2]

AAS: Qualitative and Quantitative, conc of metals and metal ions, e- in vaporised metal atom moves from ground state to excited then back again.

AES: Similar to AAS but emission of light is observed instead of absorption.

About these two,
Which release and absorb energy?
By the way, isn't AAS from excited --> ground state?  :S

AAS is measuring the energy absorbed to go into the excited state

[ggxoxo]

AAS: Qualitative and Quantitative, conc of metals and metal ions, e- in vaporised metal atom moves from ground state to excited then back again.

AES: Similar to AAS but emission of light is observed instead of absorption.

About these two,
Which release and absorb energy?
By the way, isn't AAS from excited --> ground state?  :S

They both release and absorb energy

AAS is from ground--> excited (so we can measure absorbance); we chop light so the light released by excited electrons do not get counted in the final reading