Posts Tagged ‘LC maintenance’

How do I Replace my LC Tubing?

For those that are experienced with LC, you probably have this all figured out.  If that is the case, this might serve as a good introduction to Restek products that you can use for this.  For those that are newbies to liquid chromatography, welcome and I hope you find this useful! The best way to […]

Can I use a 100% aqueous mobile phase with my LC column?

You might be asking this because you have read that not all columns are OK to use with highly aqueous content (>95%) in the mobile phase.  Or maybe the caption caught your eye because you have recently encountered some difficulty with using highly aqueous mobile phase. There is a phenomenon called “phase dewetting” that can […]

What can I use to filter my mobile phase?

If you are using mobile phase that contains salts or, generally, any components that are weighed out for its preparation, you will need to filter the solution before using with HPLC or UHPLC. The most common type of filtration is membrane microfiltration. We sell an extensive group of products for this and they are discussed […]

What is the pressure limit for my LC column?

This is a question we get in Tech Services fairly often.  Unfortunately, we are not able to provide a published limit for every column that we produce, but here are a few of them that we have specified: For 3 and 5 um fully porous particle ROC LC columns, the maximum operating pressure is 400 […]

Is it OK to use THF (tetrahydrofuran) on my HPLC?

Well, it might be. In the early days of HPLC, THF was commonly used as a mobile phase solvent. It has eluting strength similar to acetonitrile, but just slightly stronger. Since it technically is an ether and is very miscible with water, it is sometimes useful with reverse phase HPLC. It also provides additional options […]

More Technical Service “Red Flags” – LC

This post is the second of its kind pertaining to LC analysis, all of which are an extension of a series pertaining to “Red Flags” for GC analysis. These are situations and symptoms that tell us in the Tech Service group that something is just not right. As we discussed in the first post, Technical […]

Technical Service “Red Flags” – LC

This post is an extension of a series of posts pertaining to “Red Flags” my colleague has written, pertaining to GC analysis. These are situations and symptoms that tell us in the Tech Service group that something is just not right. So what are examples of some “Red Flags” that we commonly see for HPLC?  […]

Resurrecting an old reverse phase LC column- should I, could I, how would I???

Well, if we had an Easter egg hunt and you found an egg that was from last year or the year before, you could probably tell the difference and you would know pretty quickly if it had gone bad.  Let’s just say that is not so easy with HPLC columns. If you’ve dealt with this […]

Do reverse phase HPLC columns really need conditioning?

  Well, it’s partly a matter of semantics sometimes, but there is usually nothing drastic that you need to do to get your HPLC column going if it is new.  There is no baking at high temperatures involved like you might do for GC or that sort of thing. You do, however, need to equilibrate […]

Building up pressure on HPLC?

We’ve all experienced a pressure error on HPLC at some time or another. Here are my best suggestions on handling them. Establish ground rules-This will help to define the problem and distinguish if there really is one. 1.     Check your programmed max pressure limit. Be aware of what the operating limit is for your system and […]