"How Long Will a GC Column Last?"

Once of the most common questions in technical support is “how long will my GC column last” or perhaps “what is a typical lifetime for a GC column.”

Unfortunately, these are very difficult questions for which there are no definitive answers. Why? Because column lifetime always depends on a wide range of variables such as…

• Are samples relatively clean or dirty and did the column take a “bad sample hit?”
• Is a guard column being used to protect the analytical column from contamination?
• Is the GC carrier gas purified using oxygen, moisture, and hydrocarbon filters?
• Is column maintenance being performed on a regular basis (trimming/conditioning)
• Is the column exposed to pH extremes (<4 or >8) that may damage the phase?
• Is the (fused silica) column coiled to a very small diameter, thereby stressing the tubing?
• Does the analyst perform a thorough leak check of the column installation and the analytical system using a handheld electronic leak detector (or perform an air & water check via mass spec) every time the column is installed and periodically thereafter?
• Is the column stored in its box with the ends sealed or capped when not in use?
• Has the column been taken to temperature above the maximum recommended operating or conditioning temperature or has it been excessively conditioned overnight/weekend?
• The polarity of the column (non-polar phases tend to last longer than highly polar phases).

Let’s take a look at recent real world answer to this question, which was asked by a customer and answered by a member of our technical service team:

QUESTION:

What is the expected lifespan of a capillary GC column when properly stored and used?

ANSWER:

Column lifetime is a function of proper storage and use; however, there is more that affects the lifetime. The sample matrix and what is being injected onto the column influences the lifetime. For example, a pharmaceutical company may use an Rtx-624 for residual solvents analysis by headspace GC. This column could last several years. That same Rtx-624 column could be used in the environmental industry testing samples from a superfund site.  In this case, the column might last a little over a week. Oxygen can destroy a column very quickly and a small leak that is not detected can drastically shorten the lifetime. Using a guard column can potentially extend the column’s lifetime. Additionally, routine maintenance will help with column lifetime. Quality control parameters, such as instrument calibration, system suitability, etc. will determine if the column needs to be replaced. Additionally, keeping good records for column use and maintenance will help you determine if the column may be at the end of its lifetime or if there is an issue with a column. If you typically get 6 months from a column, and now you get a few days out of a new column, you need to investigate why.  Was it a leak, sample matrix, or a “bad” column form the manufacturer?

How about a non-GC analogy?

Yesterday, I took my Jeep Grand Cherokee into the shop for routine oil change, fluids check, tire rotation, and a general “once over” by my local mechanic. It’s an “older” vehicle with very high mileage. My mechanic called me at the end of the day and said that there were no significant problems thanks to the vehicle being regularly maintained with oil changes and checkups every 5000 miles.

Oftentimes when customers ask us “how long will a column last” we ask them how long a car will run. It’s the same idea. Some cars are in the junk yard after only a few years while others (like mine) run much longer than anyone would expect. It’s all about how they are used, how they are taken care of, and/or if they “led a hard life.”

A related question that we hear quite often is “what is the shelf life of a capillary GC column.” Once again, there are no right or wrong answers and GC columns usually don’t ship with an expiration date on them – but in general, a pretty good guideline guide line is to use the column within about two years to ensure that it works well for you.

What about you and your GC columns?

• Do you take good care of them and are they well-maintained and handled with care?
• Are there things you could do better to help your valuable GC columns last longer?

Think about it and please let us know if you have any questions.