Buffer salts and pressure problems in reptile blood assay

[Bruce Hamilton]

Mark has listed some of the most common suppliers. I'm not sure if you have mentioned the ID of your column, but its quite important to choose an "in-line" or "precolumn" filter that matches the column ID.

The filters for 4.6mm ID columns are usually 3-4 mm in diameter and have about 4x the capacity to retain junk than the 1.5-2mm diameter filters used with 2mm columns.

Most HPLC column suppliers also ofter in-line filters. Phenomenex offer a range that includes a simple single-piece plastic throwaway filter that just screws into the guard column or column. I've never used it, but just like the name " KrudKatcher" .

I've used an Upchurch in-line filter that was effective, but found micro-centrifugation was more cost effective as it increased life of guards by about 5-10x, but Upchurch are expensive here...

I would highly recommend keeping your guard column in place, at least until you are certain the filter is retaining the unwanted junk, but probably even after that as well, they are still cheaper than columns.

Bruce Hamilton

[Rande]

If you are looking for a low hold up volume column pre-filter, I use the ones from Mac-Mod Analytical.

See: http://www.mac-mod.com/

These are disposable 0.5 um filters with very low hold up volume. They connect directly onto the column inlet (10-32 fitting).
I have used other units that had replacement filter discs in a reusable holder, but I thought they had too much hold up volume for my application.





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