It is current practice in our laboratory to filter mobile phase for all HPLC analysis. This includes filtering mobile phase which contains buffer, and mobile phase which is an organic aqueous mix. All solvents and reagents are HPLC grade and all HPLC system cotain a degasser and some an inline filter. Also all mobile phase are sonicated before use. There is concern that unfiltered mobile phase will damage HPLC systems , is this a legitimate concern?

Anonymous;

Filtering increases the protection you will give to some critical components in your equipment. At the same time care should be taken to use the right kind of filter to avoid introducing some "ghost signals" into your mobile phases, this is known to happen.

If you are using all HPLC grade solvents and reagents then it is less likely that you really need to filter your phases. The only chance you take is that some phases may have precipitates due to high concentrations of salts and organic solvents at the same time.

Good Luck;

Benjamin

If you only use HPLC-grade solvents filtering should not be necessary, since they were filtered by the manufacturer before botteling. However, filtering mobile phases can prevent contamination of the HPLC system. Such contamination could come from buffer salts (e.g. if not entirely dissolved) or ‘dirty’ glassware etc. Also, using very narrow i.d. tubing already small particles could block your machine or pre-filters. Filtering is the easiest step for prevention of failure outside the system

Stephan

In my lab we use HPLC or OPtima solvents which are prefiltered, and only filter mobile phases which contain dissolved solid buffers, which are only used about 10% of the time here.

At our large industrial chemicals manufacturing facility there are dozens of HPLC instruments and thousands of samples a year are analyzed. Rarely is a mobile phase filterd. It is not cost effective to do so. However, in-line filters are used to catch stuff from samples, pump seals, solvents and buffers, as well as filter "sinkers" in the eluent bottles to remove particulate from eluent.

This has been discussed before. Anyway, again: Filtration can help to keep microbes out of buffers or any other solutions in which they can exist. The more steps in a preparation of a solution, the more chances you have for introducing something unwanted, Thus, if one does not handle the filtration correctly one may introduce dirt in that step as well.

It is not necessary to filter HPLC grade solvents as you may contaminate them when you do so. On the other hand, many of new HPLC systems are equipped with on-line filters that eliminate particles if present in the mobile phase.

There is little (i.e. none) garentee that a bottle of HPLC grade solvent does not contain particulate matter. Buy the best bottle of solvent you can and filter it through a sub-micron filter membrane. Then look at the filter, there is always some amount of visible particles present, that also means that there are non-visble particles. Most of the time you can get away without filtering, but as a rule, the long term wear and tear on your hardware is lessened by filtering. Its always a tradeoff, time spent filtering vs potential pump damage.