Graphite Furnace AA vs ICP

[hikinmike]

I once worked in an analytic lab where we performed testing for metal concentrations using Graphite Furnace Atomic Absorption Spectrophotometry and Inductively Coupled Plasma systems. The protocols for testing were assigned, and I never received an answer to the question, 'Why was one system superior for a particular element?"  We had many 'lamps' for the AAS analyses, yet sometimes the directive was to use ICP.  We were testing  groundwater for elemental contaminants.

[koti]

I'm no expert on this but I suspect that varying properties of different metals or other elements/compounds you were looking to find in water require different furnace specifications. 

[CharonY]

There are quite a  few differences in performance. For example ICP has higher dynamic range and can run more easily unattended. Also, they differ in sensitivity for different metals. For standard analyses the most important bit are established and certified protocols.

[John Cuthber]

14 hours ago, CharonY said:

Also, they differ in sensitivity for different metals.

Clearly, but I think the OP's question was "Why?"

[CharonY]

8 hours ago, John Cuthber said:

Clearly, but I think the OP's question was "Why?"

Hmm i read it as why one instrument got chosen over the other. But if that is the question then the basic answer is that for refractory elements the necessary temps are often not reached even with GFAA. That being said, practically it also depends on overall method development, but also the type of ICP.  Another aspect, depending on sample, are e.g. spectral interference, where the performance of the detector would determine the respective quality of the results (but which would not be an issue in ICP-MS, for example).

Edited November 7, 2017 by CharonY

[hikinmike]

Thanks to all.  More info than I  ever received from management when doing those analyses.  Will now use your suggestions as a starting point for my net search.  Ahh...retirement and free time.  Savoring it.