How is AAS used in pollution control?

Question

Is it used to monitor concentrations in the atmosphere?

I know it's used to monitor soil samples, but how?

And it's also used to monitor pollution in water and industrial waste, right? But HOW?

Any info would be much appreciated, of even (better maybe) a link to a webpage that can give me some into on AAS and pollution. I've been looking for hours and i can't find one.

Thanks in advance.

Answer 1

AAS is atomic absorbsion spectrophotometer.
You have to make standard series of cation you want to test for quantity, of known concentrations.
Then you mesure their absorbance with AAS on specific wave lenght.
Make a graph, where on Y-osis you put absorbance (A), and on X you put concentration (C).
Then you mesure the absorbance of your sample. Once you have the absorbance you can read the concentration from your graph.
Using this concentration you can say that in some sample there is more or less of some substance and say that it is or is not poluted (air, water, ind. waste...)

Answer 2

Atomic Absorption Spectrophotometry is a device which analize metal atoms in a liquid sample (most commonly aqueous solution). The principle is relatively simple: Any atom excited by temperature is able to absorb certain amount of energy relative to its concentration in solution. Every element has its own and unique bands or wavelenghts at which they absorb energy (Not the whole spectra) So, if you want to analyze copper, you use a lamp that produces the characteristic radiation of copper. This radiation passes through a controlled flame or vapor and according on the concentration of the element, is the radiation absorption in agreement to Beer's law. Standards of known concentrations are used to calibrate the system everytime it is used. So, to analyze a sample you must have it in aqueous solution. If it is already (like a water sample, seawater, condensate of a boiler, and municipal waste streams) you just adjust the chemical conditions of the sample to make it similar to the standards. If it is a solid (like a soil sample, a sludge or alike and a metal sample) you must dissolve it using strong mineral acids first. Air and gaseous samples cannot be analyzed using this technique, but you can collect particulate matter out of it using a filter for suspended particles, and treat the filter as a solid that can be attacked by mineral acids. AAS has great advantages, such as ease of operations, it is fast, relatively cheap to operate and has good precision, but it also has its limitations such as the detection limit, and the fact that at high concentrations beer's law fails and the precision can be compromised. There is so much to say that this space is not just enough.

by the way, AAS has several competitors. Some say that ICP is better than AAS for environmental samples.