Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Pippen_AintEasy on August 18, 2017, 02:39:05 PM
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What are the best techniques to determine/confirm what species of complex ions are in a solution? Also, can these be used to determine the concentration as well?
I know that a lot of solutions containing transition metal complexes have bright colors which indicates they are absorbing light in the visible spectrum. In this case I'm guessing you could simply use a uv-vis spectrophotometer and identify the species based on the wave-length of light being absorbed, and the concentration based on the intensity of light being emitted (beer-lambert's law)?
However, what could be used in the case of t-metal complexes that do not seem to absorb light in the visible spectrum (clear in solution), such as [TiF6]2-, [NbF6]-, etc...Does this require detecting spectra in the infrared range? If so, is there a technique that uses IR and/or Raman that can tell you concentration?
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I think you can run quantitave IR. But if you realy need to be precise with the concentration then something like AAS migh be better (in case you have only one species present in solution). If you want to know the identity of species then mosbauer spectroscopy is pretty powerful but not sure how easy is to get the required source for your metals
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I feel like there is a version of mass spec out there that would do the job, but I can't think which one at the moment. Maybe ICP-MS?
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I feel like there is a version of mass spec out there that would do the job, but I can't think which one at the moment. Maybe ICP-MS?
That could work but I feel like the condition would destroy the ligands so you would pretty much only got information that you have the metal in the solution without any other information
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ICP-MS can be front-ended with chromatographic separation for speciation analysis (e.g., HPLC-ICP-MS for quantitation of organic and inorganic arsenic). Naturally the plasma blows just about everything apart, but if you know the retention times of various ions on your column, you can back-calculate the relative concentration of each species in solution as it passes through the column and into your plasma.
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There we go, that's what I had in mind. Thanks Corribus. This is definitely not a trivial undertaking though