Today I will be mixing up some reagents for THC and CBD testing. These tests are a subjective, reagent based, test. They will not give us an absolute number such as 20% THC or 8% CBD. What they will allow us to do is compare samples and say which one has more CBD/THC than the other(s). This will be particularly useful for my auto projects to determine which cultivar(s) to continue breeding.
**We will be working with chemicals, so let’s be as safe as possible. A respirator, protective eye glasses, and gloves just to be safe. I also suggest having a sink or eye wash station close by and a well ventilated space to work. **
First weigh out 5 grams of either the vanillin (THC) or potassium hydroxide (CBD). Shown here is the potassium hydroxide (KOH).
After the reagents are made, place them in a labeled amber bottle for later use. Shown here are both reagents mixed and ready to be bottled.
Next we need to decarboxylate the buds before testing. Heat the oven to 240°F. Weigh out about 0.75 - 1.00 grams of cannabis and make a little tin foil pouch. Use a Sharpie marker to identify different samples. Place the packets in the oven at 240°F for 40 minutes. Here I have several samples, Grass Monkey 3, 5, 7, 8; Creme Brulee 1,3,4,7; Diamonds and Pearls 1, 4, 8; and Juanita la Lagrimosa.
For each sample weigh out 0.50 grams in a shot glass and add 5.00 grams of denatured alcohol. Mix well and let set for 30 minutes. After this, decant the liquid off the top without getting any plant matter in with the sample. This is your extract for testing.
The first test will be the Duquenois reagent test for testing THC. This test has been modified to eliminate the use of chloroform. Get a glass vial and label it with our sample ID. Next add three drops of our cannabis extract, followed by 10 drops of the 5% vanillin reagent. Now, carefully add 10 drops of 37% hydrochloric acid in the same test vial with our reagent and extract. Mix well and wait for color change. This can take up to 30 minutes. The color should go from a light blue or purple to a dark blue or purple color depending on the amount of THC.
The next test will be the Beam reagent test for testing CBD. Get a glass vial and label it with our sample ID. Next add three drops of our cannabis extract, followed by 10 drops of the 5% KOH reagent. Mix well and wait for color change. The color should go from a light pink or purple to a dark pink or purple color depending on the amount of CBD.
The results of these tests were pretty much what was expected. These are almost all the same with the exception of Juanita la Lagrimosa (labeled JLL). The Juanita clearly showed a lighter color in the THC test and a darker color on the CBD test. I have previously tested this strain at 8% THC and 8% CBD. So, these results are inline with what I was expecting.
The original beam test used a non-polar solvent (naphtha) for the extraction. I would like to try that for the extract again as it eliminates much of the green color making the results easier to read IMO.
Source:
https://www.icmag.com/ic/showpost.php?p=8180934&postcount=2