Can you explain me some problems of the coupling of HPLC to ICP-MS in element speciation? What are the problems in coupling ICP-MS and what problems we will face in coupling HPLC-ICP? What are the solutions and what kind of facilities we can use to solve the problem?
I found some information in below link (pdf), but it wasn't enough:
http://www.chem.agilent.com/Library/applications/5989-6160EN.pdf
I am not that expert in this field, but I believe ICP-MS has very disturbing solvent effects measured directly from organic solvents. This means that results from different organic solvents are barely comparable and even the absolute value is questionable. For this reason all the samples for ICP-MS are concentrated and diggested in a strong acid that dissolves the metal. The measurement is then carried out from a diluted (~2%) aqueous solution.
Not much to add to what Imre said there for ICP really. On the HPLC side of things though...
As Imre said, ideally you want to be submitting samples for ICP in water as the solvent, and whilst you can submit 100% aqueous samples for HPLC, an 100% aqueous mobile phase will irreversibly destroy most standard C18 reverse-phase columns. If you need to go down this route, make sure you invest in a good column that is capable of handling 100% aqueous mobile phases. Look for things like increased hydrophobicity (C27 to C30 as opposed to C18), polar endcapped, or polar embedded groups. Most manufacturers will state what conditions the column is suited for.
What type of speciation work are you looking at doing. There may be a number of thing to be considered when setting up a hyphenated technique like LC or HPLC-ICP-MS. As mentioned the choice of columns and mobile phase is important. The preference for ICP-MS as stated is normally an aqueous phase although small amounts of solvent are easily tolerated. Initial set up of the ICP-MS normally requires tuning and optimization. Ideally it would be good to be able to do this without going through the HPLC system so a switching valve to allow direct aspiration of the tuning solution etc. (bypassing the column at the very least) would be ideal. The flow rate of the HPLC is also important. Most ICP-MS system depending on the introduction system will have flow rate between 50 uL to
Thank you all for your answers,they were really helpful.
It's a water analysing Judy Vaive (determination inorganic elements like Sb speciation in a special water reservoir) , I think I should use RP-HPLC-ICP-MS with low flow rate (around 100ul/min).
You also want to look at stabilization of the Sb (or other elemental) species on collection of the water sample. Different approaches may be required for different elements and testing with only aqueous standards or synthetic water samples will probably not give you the same results as real water samples. You will normally get oxidation of SbIII to SbV fairly quickly with no stabilization and high Iron samples may have additional issues. Once you get your column chemistry worked out (watch out for matrix effects from your mobile phase,), you will need to make sure you are able to preserve the Sb species in your samples.
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