ICP-MS and ICP-AAS 1

[deenor]

Hi there,
What are the differences between Inductively Coupled Plasma-Mass Spectrometer(ICP-MS)and Inductively Coupled Plasma-Atomic Absorption Spectrometer(ICP-AAS)?

Thanks
deen

 

[kenvlach]

ICP-MS seems to be the best method of elemental analysis – detects all the way down to at. wt. 3 (maybe even 2 – I haven’t seen newest instrument specs.), least interference, lowest detection limit. Lots of info – see below.
AA needs source lamps to supply the spectra of the elements being measured – do you perhaps mean atomic emission?

ICP-MS — Comparison of Techniques: High-Resolution
Advantages are high resolution, low interference, low detection limits. A disadvantage is “Slow Analysis Speed: Because the high-resolution mass analyzer uses an electromagnet to separate the masses, it must change the magnetic field strength between one mass and the next.”

http://www.missouri.edu/~murr

http://www/pages/ac_icpms8.shtml

Metals Analysis by ICPMS
“ICP-MS is far superior to any other atomic spectroscopy technique for measuring total element concentrations in solution… ICP-MS actually offers the best of both worlds: 10-100X better sensitivity than graphite furnace AA with the multi-element speed of ICPOES. In comparison to ICPOES, the mass spectra are much simpler than the optical emission spectra. Most heavy elements exhibit hundreds of emission lines, but they have only 1-10 natural isotopes in the mass spectrum.” “

http://www.wcaslab.com/icp-ms_index.htm

Selected Reviews on ICP & ICP/MS LC/MS Instrumentation
A listing of review articles, some of which are comparisons.

http://www.lcms.com/rev_inst-icp.htm

 

[T100]

The best answer to this question is with another question: what do you want to measure? ICP-MS indeed has much better detection limits, and potentially better resolution than ICP-OES, but if you want to measure the concentrations of major consituents (as opposed to trace concnetrations) you're better off with OES than MS. In adddition, there are two principle types of MS instruments: quadrupole and magnetic-sector. The former have a mass resolution (deltaM/M) of 1, while the latter can have mass resolution as high as 10,000. The quadrupole instruments are very common and far less expensive than the mag sector ones, but if you happen to want to measure an element that has an isobaric interference you may not even be able to do it with mag-sector.

In short, one isn't necessarily better than the other, they both have utility. We have both instruments located side-by-side in our lab, and they are used equally often.