How long is the durability of Acetonitrile and of Tetrahydrofuran in normal glass bottles as HPLC eluents? Is it true that the durability for them is much shorter than for other organic solvents?

I don't know about acetonitrile, but I do know that THF forms peroxides, unless you purchase it with stabilizers in it (or add them yourself).

As a matter of habit, I typically will not have any mobile phase older than 5 days. Pre-mixed mobile phases that are sparged should be prepared every 24-48 hours. Acetonitrile is stable, but as with all other mobile phases, you want to aviod the accumulation of particulates in your reservoirs. THF needs to be treated with some care. I usually avoid preserved THF because BHT can be a pain if you're running gradient RPLC, especially with UV. I buy it in 1 liter bottles, sparge it with Helium when in use, and remove it from the LC and seal tightly when I'm done. I've been running this way for many years and my pumps are fine, I can't remember the last time I clogged a column, and the occurrence of systemic contamination is usually pretty low.

Holler if you need any more information.

Chris

I agree with above. We use ACN and just keep adding to the reservoirs. For THF, we use unpreserved THF and also purchase in 1 liter bottles. We use THF routinely, and we use brown low-actinic glass reservoirs for it (better than covering clear glass with aluminum foil). These bottles are available with various tops, even threaded GL45 to fit HP1100. By the way, we have the HPLCs under an exhaust hood, and even the waste reservoir is vented to exhaust, nice when working with THF. By the way, we would rather not use THF because of its odor, etc., but we have found THF necessary for some assays to achieve separations not possible without its use.