Jump to content


Photo
- - - - -

Molecular vs. Atomic Absorption Spectroscopy


  • Please log in to reply
4 replies to this topic

#1 foolishone

foolishone

    Quark

  • Members
  • 16 posts

Posted 12 September 2006 - 06:28 PM

Does anyone know the difference between molecular absorption spectroscopy and atomic absorption spectroscopy? I know AAS destroys the sample, but I need to know another diffference? I tried searching but can't really find anything about MAS. Is there another name for MAS?

Thanks,

fo
  • 0

#2 Dak

Dak

    Wearing a hat since '06

  • Moderators
  • 3,347 posts
  • LocationUK

Posted 12 September 2006 - 06:36 PM

afaik, MAS is usually reffered to by the type of wavelength it's adsorbing, eg infra-red adsorption spectroscopy, UV-AS, or just electromagnetic adsorption spectroscopy, so you might want to search for terms such as those...

i think AAS measures the adsorption of the constituent atoms across a region of the EM spectrum, whilst MAS measures the adsorption of the molecule across a region of the EM spectrum.

I dont think AAS can identify substances, unless they are elements... i know it's used to identify heavy metals, but you can't, say, ID cannabis using AAS (tho i might be wrong)
  • 0
In 2005, 35% of those who voted, voted Labour. This is only of 22% those allowed to vote, and just 15.5% of the population; yet Labour have 55% of the power, giving them total control.

#3 swansont

swansont

    Shaken, not stirred

  • Moderators
  • 26,509 posts
  • LocationWashington DC region

Posted 12 September 2006 - 08:10 PM

Just to note, adsorption and absorption are two distinct processes.
  • 0

Minutus cantorum, minutus balorum, minutus carborata descendum pantorum                                   To shake my vodka martini, click the up arrow ^

I am not a minimum-wage government shill

My SFN blog: Swans on Tea                                                           

 

 

                                                                                                                     

 

 


#4 swansont

swansont

    Shaken, not stirred

  • Moderators
  • 26,509 posts
  • LocationWashington DC region

Posted 12 September 2006 - 08:23 PM

I know AAS destroys the sample


I assume you mean that in order to use AAS on a sample, you have to atomize it; simply absorbing a photon isn't going to do anything to destroy the atom itself.

AAS is only going to involve electronic transitions, as there are no vibrational or rotational states to interrogate. It can tell you the constituent atoms but not how they were originally arranged.
  • 0

Minutus cantorum, minutus balorum, minutus carborata descendum pantorum                                   To shake my vodka martini, click the up arrow ^

I am not a minimum-wage government shill

My SFN blog: Swans on Tea                                                           

 

 

                                                                                                                     

 

 


#5 jdurg

jdurg

    Resident Expert

  • Resident Experts
  • 2,171 posts
  • LocationSE Connecticut, USA

Posted 25 September 2006 - 02:04 AM

I assume you mean that in order to use AAS on a sample, you have to atomize it; simply absorbing a photon isn't going to do anything to destroy the atom itself.

AAS is only going to involve electronic transitions, as there are no vibrational or rotational states to interrogate. It can tell you the constituent atoms but not how they were originally arranged.


Exactly. MAS will tell you that Carbon atom 1 was bound to oxygen atom 2, while AAS will only tell you that you have two oxygen atoms and one carbon atom but not how they were arranged.
  • 0




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users