Aas (1 Viewer)

[horsegal]

What do you know about AAS?What do we need to know about it, I just don't seem to get what it is.

 

[Nakashima]

AAS is a sensitive machine used in the quantitative analysis of metal ions in solution. It can detect and measure concentrations of as low as ppm (parts per million) and sometimes ppb (parts per billion).

In a nutshell, it uses a cathode lamp which emits the emission spectrum of the analysed metal. The incident light passes through the furnace or flame which has vapourised the metal ions. Electrons in these metal ions are excited to a higher energy level and hence some light is absorbed. The amount of unabsorbed light (from which the level of absorbance can be calculated) is recieved by a detector.

^ That's very brief. If you want details, read about AAS in your textbook.

Make sure you understand atomic emission spectroscopy before you try to understand AAS. Otherwise you'll just be blankly memorising stuff.

 

[pLuvia]

What it is, and how it works, basically what Nakashima said. What it is used to measure i.e. Trace elements and how it is important to scientists

 

[priesty]

AAS for me was also the worst thing to study.... i found it hard too and resorted to memorising set sentences to put into paragraphs in my responses... The text book just made it harder to understand

Nakashima summarises it good though *thumbs up*

 

[Rekkusu]

Also, a point is that the metal ions used in AA spectroscopy must be in liquid form, or else it cannot be analysed.

 

[tennille]

If the sample is a solid, you can dissolve it via fusion or by acid digestion techniques (common acids include HNO3, H2SO4 and HCl). Also, before vaporisation, usually it is good to nebulise the sample solution. That way, it will be easier to vaporise it.

 

[horsegal]

Thanks everyone, that has been very helpful!!!

 

[.ben]

You know the dotpoint "deduce the ions present..." do we just remember a flowchart for that?

 

[Mountain.Dew]

You know the dotpoint "deduce the ions present..." do we just remember a flowchart for that?

i highly doubt that you do. if a question that involves such a flowchart pops up in the exam, they will most likely give you the actual flowchart.

im not too sure, please clarify with the teachers

 

[.ben]

Really i hope so lol, but if we do have to remember the ions test, do we need to know the solubility rules and the colour of the precipitates tests?

 

[Riviet]

It is very useful to know the solubility rules, and it does help to know some of the common precipitate tests, although I've seen in past questions that the flowchart thing is given to you.