A Tale of Two Columns (CLPesticides and CLPesticides2)—Part IV: Fast 8081 Method Using GC Accelerator Kit

The moment has finally come to see how we can use the GC Accelerator to get the most horsepower for your 8081 analysis.  If you’ve been following this blog series, you will remember that in Part II, I talked about ways to make your runs faster.  I also showed you our previous fast “7 minute” method, using some of those tricks.  One of the limiting factors for that method was oven ramping ability; the ramps at the beginning and end were as high as a 120V Agilent GC would be able to maintain.  Fortunately, we have enough resolution at those points in the run to actually increase the ramp rate without causing any coelutions.

So how do we do this?  You’ve probably figured out by now that the answer is the GC Accelerator Oven Insert Kit.  With this kit, simply increasing the initial ramp rate and final ramp rate will allow you to elute all analytes in around 5 minutes, with a total oven cycle time close to 10 minutes.  In addition, flow rates can be increased to further capitalize on this benefit.  If, for example, your current total cycle time for 8081 is close to 20 minutes, this will effectively allow you to double the amount of samples you can process in a given amount of time.

The examples below demonstrate this fast method on both 0.32mm ID CLPesticides column as well as 0.25mm ID CLPesticides columns. Table 1 details the products you will need to try either of these methods.  Note that the columns are custom products and are not wound on cages.  This is necessary to fit both analytical columns in the oven with the entire GC Accelerator kit.  Refer to Part III of this series for detailed instructions on how to set this up.

 

Table 1: List of products needed to perform the methods below.  Both the 0.32mm ID columns and 0.25mm columns are listed for you to choose which pair works best for you.  All columns were custom products that are not on cages.

 

Figure 1: Fast GC Accelerator method on 0.32 mm ID Rtx-CLPesticides and Rtx-CLPesticides2 columns.  All analytes elute near 5 minutes with a total GC cycle time of around 10 minutes.  Link to chromatogram and conditions found here: https://www.restek.com/images/cgram/gc_ev1498.pdf

 

Figure 2: Fast GC Accelerator method on 0.25 mm ID Rtx-CLPesticides and Rtx-CLPesticides2 columns.  All analytes elute near 5 minutes with a total GC cycle time of around 10 minutes.  Link to chromatogram and conditions found here: https://www.restek.com/images/cgram/gc_ev1496.pdf

 

So there you have it!  The GC Accelerator kit can be used to increase sample throughput for dual column methods, in addition to its original intent to be used for GC-MS.  While the above example uses method 8081, similar changes could be made to other methods.  I encourage you to use Restek’s Pro EZGC Chromatogram Modeler to explore speeding up methods using increased ramp rates attainable with the GC Accelerator kit.  Any column can be ordered without a cage by attaching the suffix “-051” to the column catalog number.

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