First of all, you should take into account that you need dissolve the sample of heterogeneous catalyst in order to obtain a solution containing all the elements present in it and suitable for introduction in the ICP-MS equipment. This is a critical step in the ICP-MS analysis. In fact, if the sample is not properly dissolved prior to carrying out the experiments, the obtained results will be wrong. There are a number of methods and chemical agents usually employed for dissolving the catalyst sample. However, most of them usually used acids such as nitric acid, hydrochloric and hydrofluoric acids, sulfuric acid, and so on. The acid that you must use is determined by the nature of the catalyst sample. Thus, if your sample contains noble metals, such as gold, palladium or platinum, you should use aqua regia (i.e., a mixture of nitric and hydrochloric acids) or other strongly oxidizing acid mixture. If your sample contains a support of silica or different silicon compounds, you can use hydrofluoric acid. As far as the methods are concerned, you should aslo take into account the nature of the catalyst. Some methods use microvawe to accelerate the process.

I hope this will be helpful for you.

Best regards,

Adrián B. Bogeat

I am unsure as to what you want to measure in your catalyst.  You need to be much more specific.  Is it the metals content? As Adrián states everything you need to analyze must be soluble.  If you have an insoluble matrix and soluble (say in acid) metals then you'll have to dissolve the metals, allow the matrix to settle, and then finally filter through a 0.22 um filter (or better) to prepare the solution.

Can we use NaOH or KOH solutions to dissolve silica?  I need to find out the metal content in the catalyst.

Then just dissolve the metal off the matrix.  Settle and filter.  Why do you want to dissolve the silica?

Shall I use any acid or highly basic solution having pH=12?

Thank you Adrian and Alan F. Rawle.

If you are dissolving the metal(s) off, then use the appropriate acid or acid mix.

I made supported Pd, Pd-Au, and Pd-Ag catalysts at nominally 5wt% metal loading back in the 70's. - that's the 1970's not my 70's.... Simply I'd dissolve the metals off a known mass of the (silica, alumina, C, BaSO4, CaCO3) support and dilute in order to get solutions suitable for AAS analysis (no ICP-MS in my day!). 

There seems to be a conflict in your 2 sentences "Can we use NaOH or KOH solutions to dissolve silica?  I need to find out the metal content in the catalyst".  You are trying to find the metal loading not the support content (which is [100% - wt% metal] anyway)....

We still appear to be unsure of the metals in your system - I assume the support is silica from what you say.  Please provide more information.

I agree. Just acqua regia normally is the better solution to solve metals. Afterwards you need to dilute, you cannot introduce pure acqua regia into the machine. Normally a 2-3% conc. it's OK. Then you filter the solution and this is prepared for measurements.

at the first step how must keep our tisse samplews or bood samples? can we store them at -20

@ Hadiseh Your question is not related to this one which is over 2 years old. Post a separate question and you may have it answered - I assume that you know how to do this... Don't add a different question to the thread as it confuses people looking for answers.

The samples should be in solution form when analyzed by ICP-MS. After dissolution the sample should be diluted in such a way that the acid concentration is not more than 5%. It is very essential to avoid isobaric interferences (due to molecular species formed) as well as corrosion of sampler and skimmer cones ( nickel).It is better to use HNO3 compare to HCl, H2SO4, HClO3 etc. Before analysis, it should be assure that the total dissolved solid (TDS) is