Part 17: Finding Pure Essential Oils

fused silica GC column
Testing is conducted through this fused silica GC column with its tube .25 microns in diameter.

Other factors can also vary the results of an analysis. If the essential oil sample injected into the Gas Chromatography (GC) instrument is diluted, the computer may or may not give a correct analysis. Another aspect is called “ramping” the temperature to cause more separation. This means that as the essential oil flows through the column, the temperature is increased at certain intervals.

Another area of importance is where the operator sets the programming for the calibration of the instrument to begin reading the molecules. The setting can dramatically change the outcome of the test. Many laboratories set the area reject at 50 to 100, which means it will only read the larger molecules. If the instrument is set at an area reject of 50 or 100, it cannot determine if all or some of the molecules are actually measured or missed.

Young Living’s area reject is set at 0.00 for the first test to ensure that we do not miss any small molecules. If there are any identifiable molecules that have any significant value, we may set the area reject at .02 or .05 to test further for continued molecule identification.

Gas chromatography analysis is very complex. The interpretation is even more complex and difficult. You cannot learn to do it by reading a book or taking a chemistry class. In fact, years of actual laboratory experience are needed to understand GC chromatography analysis.  

I have been attending classes and working in laboratories since 1996 to learn how to operate a GC instrument and how to interpret the analysis. I have been mentored by Dr. Hervé Casabianca, Director of Natural Product Research at CNRS labs in France. Cole Woolley, YL Director of Research and Discovery, who is also an expert in GC-MS, says, “Interpreting GC analysis to verify the purity of essential oils takes years to master.”

To be continued . . .