Archive for the ‘Troubleshooting’ Category

Tailing solvent peak during split injection? Check your column installation distance!

When performing splitless injections, it is not uncommon to witness a tailing solvent peak, given the large amount of solvent introduced onto the column over a relatively long period of time.  For split injections, however, only a small portion of the solvent loads onto the column and it occurs very quickly. This results in a […]

Are My Shut-off Valves Contaminated?

Shut-off valves provide a convenient means to control gas flows and are often used in conjunction with gas chromatography systems.  There are several types of shut-off valves including ball valves, plug valves, and diaphragm-sealed valves.  Some of these valves, ball and plug valves included, use a silicone-based lubricant to make opening and closing the valve […]

Annual Replacement of Cartridge Gas Filters

A significant number of instrument and column complaints are carrier gas related, which could be caused by breakthrough from filters that are not replaced in time. The possible consequences of a filter breakthrough are: Gas distribution system behind the filter will be contaminated (fast cleaning nearly impossible, bleeds for months) Instrument gets contaminated, expensive maintenance […]

A better way to configure your EZ No-Vent GC-MS Connector

If you are using the EZ No-Vent for Agilent mass spectrometers (cat.# 21323), you are probably tricking your instrument into working properly by inflating the length of your column in your acquisition software. If you have MassHunter, or a recent version of MSD ChemStation  (G1701EA), you don’t have to do this. Instead of configuring your […]

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 […]

GC compounds – poor peak shapes and missing peaks

One of the most common questions I am asked by customers is “Why is my peak shape so poor?” Another is “I do not see a peak for my compound, what should I do?” Sometimes they are developing a new method and have no experience with the compound(s) of interest; other times things worked well […]

How (Not) To Cut Your Capillary Column

There are numerous ways to cut a capillary column. Restek has several tools to accomplish this job. There are sapphire scribes, ceramic scoring wafers, wafers with a handle, and diamond blade column cutters. There are also some tools manufactured by other companies that will cut a capillary column. The choice is typically personal preference. No […]

Don’t forget about your lab’s moisture traps/filters, especially when it’s summer

One of the common issues which arise in laboratories during the summer is moisture in the gas lines. Although I never quite understood how this would happen when using gas cylinders, it does, especially when a manifold system is used, or if the length of tubing from the gas source to the instrument is longer […]

Troubleshooting Injection Volume Variation in the Concurrent Solvent Recondensation – Large Volume Sample Injection Technique

I’ve started receiving a number of questions about the large volume injection technique called Concurrent Solvent Recondensation – Large Volume Sample Injection. Most recently, a question came through the Tech Service group about injection volume variation. I had encountered a similar problem when working on the 50 µL injection for the combined 1,4-Dioxane and Nitrosamines (EPA […]

Need parts for your Agilent 1100? HP 1050? Restek has you covered.

As of May 31, 2015, 1100 Series HPLC systems were categorized “End of Guaranteed Support” (EGS) by Agilent. Agilent would prefer it if you purchased a new system from them, but 1100 HPLCs are dependable workhorses. Why not keep them running with instrument replacement parts from Restek? Check out our selection, easily sorted by instrument and module: […]