Chromatography Forum

I am relatively new to vacuum degassing and wondered why the reservoir bottles are coated for safety (implosion risk I presume).
Has anyone had a problem with their vacuum degasser and is there anything I can do to prevent a problem?
Coated reservoirs are expensive you know!!

Thanks for any replies

A vacuum dessicator can be used, place you mobile phase bottle inside OPEN!!! and let the pump go... Filter Erlenmeyer are also designed to stand vacuum, just put your liquid inside, put a plug where the Funnel goes and pull vacuum.
If you get the wrong glassware..... an implosion has about the same effect as an explosion (talking from experience here).

Thanks HM Mueller,
Are you saying that I have an implosion risk if I keep my reservoirs "semi-sealed" - ie with the lid screwed on?
Should I keep the lids loose when connected?
Is there a risk of an implosion within the degasser "box" itself?

I was told at some point that the bottles were coated in case of explosion due to overpressure, for those people who bubble helium through their mobile phase.

Even without a vacuum degasser, if your reservoirs were perfectly sealed, you would eventually pull a vacuum because you would be removing solvent and not replacing it with anything. In my case at least, the port where the mobile phase tubing enters the lid of the reservoir allows enough air leakage to prevent this from happening.

WK,

My understanding as to the reason behind the use of a safety coating on eluent bottles is that this is intended to deal with the variety of different techniques commonly employed for dealing with dissolved gas problems, some of which may entail some risk of either implosion or explosion. Generally, there is no negative pressure on the eluent bottle even when you have a vacuum degasser in your analytical system (the vacuum employed in this case is inside a sealed chamber in your pump or vacuum degassing accessory) so there really isn't an implosion risk with a standard eluent degasser system. The reason for the safety coating is that some people prefer to apply positive pressure to the bottle and failure of the pressure regulator may result in a rather dangerous situation without the safety coating.

Of course, if you are vacuum degassing your eluent in the eluent bottle prior to using it with your instrument, there is also some risk of implosion (although extremely small) so even in this case the safety coating is beneficial. Having said that, I generally use the uncoated bottles for most of my work since they are considerably cheaper and the risks of either implosion or explosion are minute.

Chris, you are probably working with eluent bottles especially made for that purpose. A lot of people use any bottle available, or normal Erlenmeyers, these often have faults, or thin flat bottoms, and may implode on pulling vacuum.
WK, what I was saying is: don´t place a hermetically sealed, off the shelf bottle into a vacuum.