Measure THC, CBD and more in Real Time During CO2 Extraction with Near Infrared

by Paul on August 7, 2021

Finding the best operating conditions for your extractor can be a slow process.  CO2 extraction of cannabis presents some specific challenges. THC doesn’t take long to extract but THC-a can take a long time. How do you know when to stop extracting? You can stop extracting from time to time and take samples for HPLC analysis. This is time consuming and labor intensive. Alternatively, you can use Near Infrared (NIR) to continuously monitor the concentrations of

  • THC
  • THC-a
  • CBD
  • CBD-a
  • Minor Cannabinoids
  • Total Cannabinoids
  • Fats/Waxes
  • Terpenes
  • Ethanol

Sometimes ethanol is used to aid in the extraction of THC-a during CO2 extraction. Some systems that bleed in the ethanol are rudimentary and there is no way to confirm if the correct amount of ethanol is being added or not. The ethanol concentration can be monitored by NIR to assure that the concentration is correct and constant.

NIR Spectra of total cannabinoids from CO2 Extractions
NIR Spectra of Total Cannabinoids from CO2 Extraction
CO2 extraction total cannabinoids NIR
Total Cannabinoid Calibration

An NIR sensor can be installed in a flow cell so that measurements can be taken as the CO2 and extract flow through piping from the extractor. The NIR flow cells are rated up to 2,500 PSI which is well within pressures used in CO2 extractors.

Flow Cell for Real Time Near Infrared Measurement
Near Infrared Flow Cell for THC and CBD Measure in Hemp/Cannabis Extractors

How does Near Infrared measure cannabinoids?

Wavelengths in the Near IR are beamed into the extract during extraction.  A detector measures the response of the material to the various wavelengths of Near IR and compares this to a calibration model.  This produces a real time measurement of THC, THCa, CBD, CBDa and other cannabinoids. 

NIR Flow Cell for CO2 Extractor
NIR Flow Cell for CO2 Extractor

Posted in Extraction, Near Infrared Measurement of THC and CBD

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