# Filter papers for removing left over particles in diluted solutions?



## Seth Baldwin (Jul 4, 2021)

Can someone recommend me appropriate whatman filter papers (not coffee filters) for keeping my solutions ash free after dilution.

Thanks


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## IanG (Jul 5, 2021)

While I have various boxes of Whatman papers I always use coffee filters in the darkroom, with any filter paper Whatman or Coffee you should refilter the first few mls anyway.  If I was using Whatman papers Grade 4 is sufficient.

Ian


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## Seth Baldwin (Jul 5, 2021)

Thanks. I'm confused what you mean by refilter the first few millilitres? Do you mean filter the solution multiple times in general or something else?


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## IanG (Jul 5, 2021)

In laboratory work it's common to either run some distilled or de-ionised water through a filter, or some of the solution, So typically if filtering 1 litre you  might start filtering and then after say 100ml return that to the container you are filtering from, this removes any particles on the new filter paper.

Ian


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