Organochlorine Pesticides Analyzed by Gas Chromatography – Electron Capture Detector with Hydrogen Carrier Gas and Concurrent Solvent Recondensation – Large Volume Splitless Injection

Are you a gas chromatographer feeling the sting from either not getting helium carrier gas or paying too much money for it when it is available?  Hydrogen is a completely viable alternative and I recently used it to do fast GC-ECD organochlorine pesticide analysis with a 30m x 0.25mm x 0.25µm Rtx-CLPesticides column.  I also used Concurrent Solvent Recondensation – Large Volume Splitless Injection, 10 µL in this case, by press-fitting a 5m x 0.53mm retention gap to the analytical column.  

Large volume injection is a powerful technique that can save time and money.  If time is money, then I was just redundant, so I’ll not say it again.  There are three main benefits: 

Instead of spending valuable time concentrating sample extracts to 1 mL (through solvent evaporation) and risking losses of the most volatile compounds, stop at 10 mL and inject 10 µL instead of 1 µL (same amount on column). 

Extract a 100 mL aqueous sample instead of a 1 liter sample and inject 10 µL of the final extract instead of 1µL.  The monies saved from shipping 100 mL samples instead of 1 liter samples can be HUGE.  

Inject 10 µL of drinking water, groundwater, or other “clean” extracts to improve your limits of detection and limits of quantification. 

The chromatogram shown in this post is about 10 min long.  The selective CLPesticides column allows compression of the analysis time by resolving compounds like cis-Chlordane and Endosulfan I, which tend to coelute on “5” columns.

 

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