Hello, I’m taking a dive into TLC to try out testing ballpark thc percentages on different phenotypes to make a better guess at which ones to send in for rec compliance testing.
I’m seeing a ton of canna TLC kits, but I’d like to piece one together (im a cheap ass) however im having a hard time finding the cannabinoid chart to measure how big the dots get.
Any help is appreciated 
That’s what standards are for (isolate is cheap).
https://www.google.com/search?q=tlc+cannabinoids&tbm=isch
See if any of those are what you’re after…
Edit: alpha-cat are the folks who made up the term, you can purchase from them or make your own.
I’ve never seen that cannabinoid ruler. Pretty neat idea.
I don’t see how many rulers you get for 100 euro. seems pricey for something when you can pay $50 or less per potency test from an ISO accredited lab
There are software methods for this, I’m not sure if this is the one I was looking at originally but there appears to be a few options
Aha…that’s a good idea 
I have some recent flower that tested 28% THC at Greenleaf in Oregon and I would get a certain sized THC blot. Then I can use that blot for reference and make my own ruler of some sort? And either be above > or below < the baseline blot. Seem legit? Lol
Does anyone recommend a TLC kit or shall I piece one out?
Thanks for the reply’s
Thats interesting!
here’s another for a smartphone
and here’s the study it came from:
kids these days…you’ve never calibrated anything have you?
as a general rule, calibration is a required part of any analytical work.
No. One spot does not a ruler make. especially if you rely on the baloney you’ve been fed at the ex$pen$iary: that flower is almost certainly not 28% THC.
…but if you used isolate, some math, and a decent (calibrated) scale you absolutely could.
seems like you could use a write up on building a standard curve for TLC…
try (eg) : standard curve tlc at DuckDuckGo. although either of the software tools @pdxcanna pointed you at should delve into the concept (as they will require calibrated).
asked Bard: “how do I go about making a cannabinoid ruler for TLC analysis?”
To make a cannabinoid ruler for TLC analysis, you will need the following materials:
- A thin-layer chromatography plate (TLC plate)
- A mobile phase for TLC (e.g., hexane:ethyl acetate, 4:1)
- A developing chamber
- A cannabinoid standard solution (e.g., a solution of THC, CBD, and other cannabinoids in methanol)
- A visualization agent (e.g., vanillin stain, iodine vapor)
Instructions:
- Prepare the TLC plate by scratching a line 1 cm from the bottom of the plate with a diamond pencil.
- Apply the cannabinoid standard solution to the TLC plate at the starting line. You can use a micropipette to apply the solution.
- Place the TLC plate in the developing chamber and close the chamber.
- Develop the TLC plate for 10-15 minutes, or until the mobile phase reaches the top of the plate.
- Remove the TLC plate from the developing chamber and allow it to dry.
- Visualize the cannabinoid spots on the TLC plate using a visualization agent.
Once the cannabinoid spots are visible, you can measure the distance that each spot has traveled from the starting line. This distance is known as the retention factor (Rf) value. The Rf value is a characteristic property of each cannabinoid and can be used to identify cannabinoids in a sample.
To create a cannabinoid ruler, you will need to apply a series of different cannabinoid standards to the TLC plate and measure the Rf value of each spot. Once you have measured the Rf values of all of the cannabinoid standards, you can create a table of Rf values for different cannabinoids.
Example:
Cannabinoid Rf value THC 0.50 CBD 0.45 CBN 0.40 CBG 0.35 Once you have created a cannabinoid ruler, you can use it to identify cannabinoids in a sample by comparing the Rf values of the cannabinoid spots in the sample to the Rf values of the cannabinoid standards.
Tips:
- It is important to use a consistent mobile phase and developing time when creating a cannabinoid ruler. This will ensure that the Rf values of the cannabinoids are reproducible.
- If you are using a visualization agent that is destructive to the cannabinoids, you may want to visualize the cannabinoid spots on the TLC plate before measuring the Rf values.
- You can also use a TLC scanner to visualize the cannabinoid spots and measure the Rf values.
Please note that this is a general procedure for creating a cannabinoid ruler. The specific details of the procedure may vary depending on the type of TLC plate, mobile phase, and visualization agent that you are using.
I like that it ignored Alpha-Cat’s use of “cannabinoid ruler”
then asked: " how do I make a standard curve so I can quantitate?"
gave me two responses.
OPTION A
To create a standard curve for cannabinoid quantitation, you’ll need to prepare a series of standard solutions with known concentrations of the cannabinoid you want to quantify. These standard solutions will be used to generate a calibration curve, which will allow you to determine the concentration of the cannabinoid in an unknown sample.Here’s a step-by-step guide on how to create a standard curve for cannabinoid quantitation:
- Prepare a stock solution of the cannabinoid: Accurately weigh a known amount of the cannabinoid standard and dissolve it in a suitable solvent, such as methanol or ethanol, to create a stock solution.
- Prepare a series of dilutions: From the stock solution, prepare a series of dilutions with decreasing concentrations of the cannabinoid. For example, you could prepare dilutions with concentrations of 1000 µg/mL, 500 µg/mL, 250 µg/mL, 125 µg/mL, 62.5 µg/mL, and 31.25 µg/mL.
- Analyze the standard solutions: Analyze each standard solution using the analytical technique you are using for quantitation. For example, you could use high-performance liquid chromatography (HPLC) or gas chromatography (GC) coupled with mass spectrometry (MS).
- Plot the standard curve: Plot the concentration of the cannabinoid in each standard solution (x-axis) against the corresponding analytical response (y-axis). The analytical response could be peak area, peak height, or absorbance.
- Fit a linear regression line: Use a statistical software package or a graphing calculator to fit a linear regression line to the data points. The equation of the line will be in the form y = mx + b, where m is the slope and b is the y-intercept.
- Validate the standard curve: Analyze a quality control (QC) sample with a known concentration of the cannabinoid. The concentration determined from the standard curve should be within an acceptable range of the known concentration.
Once you have a validated standard curve, you can use it to determine the concentration of the cannabinoid in an unknown sample. Simply analyze the unknown sample using the same analytical technique, measure the analytical response, and then use the equation of the line to calculate the concentration.
OPTION B
To make a standard curve for quantitation of cannabinoids using TLC, you will need the following materials:
- A cannabinoid standard solution
- A mobile phase for TLC
- A developing chamber
- A visualization agent
- A series of different concentrations of the cannabinoid standard solution
Instructions:
- Prepare a series of different concentrations of the cannabinoid standard solution.You can do this by diluting the stock solution with a solvent such as methanol.
- Apply each concentration of the cannabinoid standard solution to the TLC plate, starting with the lowest concentration and working your way up to the highest concentration.
- Develop the TLC plate and visualize the cannabinoid spots as described above.
- Measure the intensity of the cannabinoid spots using a densitometer or by visually comparing the spots to a reference standard.
- Plot the intensity of the cannabinoid spots against the concentration of the cannabinoid standard solution. This will create a standard curve.
Once you have created a standard curve, you can use it to quantitate the amount of cannabinoids in a sample by comparing the intensity of the cannabinoid spots in the sample to the standard curve.
Example:
Suppose you have a sample of cannabis extract and you want to quantitate the amount of THC in the sample. You can do this by following these steps:
- Prepare a series of different concentrations of a THC standard solution.
- Apply each concentration of the THC standard solution to the TLC plate, along with a sample of the cannabis extract.
- Develop the TLC plate and visualize the cannabinoid spots.
- Measure the intensity of the THC spots in the cannabis extract sample using a densitometer or by visually comparing the spots to the THC standard curve.
- Compare the intensity of the THC spots in the cannabis extract sample to the THC standard curve to determine the concentration of THC in the sample.
Tips:
- It is important to use a consistent mobile phase and developing time when creating a standard curve. This will ensure that the intensity of the cannabinoid spots is reproducible.
- It is also important to use a wide range of concentrations of the cannabinoid standard solution to create the standard curve. This will ensure that the standard curve is linear and can be used to accurately quantitate the amount of cannabinoids in a sample.
- If you are using a densitometer to measure the intensity of the cannabinoid spots, be sure to calibrate the densitometer before using it. This will ensure that the densitometer is accurately measuring the intensity of the spots.
Please note that this is a general procedure for creating a standard curve for quantitation of cannabinoids using TLC. The specific details of the procedure may vary depending on the type of TLC plate, mobile phase, visualization agent, and densitometer that you are using.
which do y’all prefer?
Theres a mom joke in here somewhere 
Just kidding, just kidding. Appreciate the help I was born in the early 80’s…does a PH Pen and Brix Meter count? (Don’t answer that)
You are probably correct that its almost certainly not 28%. However, the flower testing was initiated and funded by myself for metrc compliance, so it should be fairly accurate. It is yet to be on any shelf. Had 4 other strains tested last week as well, would that be enough points of reference to at least get a visual ballpark?
Off topic Question…im curious as to why the dispensary shelf numbers would be off?
My main goal: To reference whether a certain geno or pheno tests above or below 28%. Exact percentage numbers are not needed, but would be nice i suppose.
Thank you!
Then run your “standard” on every %%*%^€ plate…
Answers the question (to the resolution of your current competence) “is, or is this not, more better than that”.
As to why the numbers in the stores are inaccurate in almost every market, I’m sure some other kind soul can point you at the reasoning and data if you can’t find it yourself.
Numbers sell flower. So higher numbers sells testing. Seen in multiple markets.
Which is why you start with isolates.
nah dude, I know this shit ain’t no 107% thc…
And why folks making their own standards recrystallize a couple or three times and figure they’re pretty close.
Hell yeah…I’ll give it a try. Thank you for the insight. I definitely have a lot to learn on this subject.
Absolutely. During the 5 yrs in the producer rec scene…I think about this quite a bit. It sounds weird hearing it from my own mouth but imo ALL rec lab tests should be done at the same exact state ran laboratory to fix this. Cuts out the boosting % results, different methods/equipment, SOP’s etc…too many variables.
I’m so not a fan of the high THC consumer trend…its bad for the plant genepool. Been growing/seed making/minor breeding projects for 16 yrs and I’m hella bummed on the general consensus of what is now deemed good weed.
" How do I take the dilutions from above and make a “spot chart” I can compare my experimental data to?"
To create a spot chart for cannabinoid quantitation using TLC, you will need to:
- Prepare a series of different concentrations of the cannabinoid standard solution.
- Apply each concentration of the cannabinoid standard solution to the TLC plate, starting with the lowest concentration and working your way up to the highest concentration.
- Develop the TLC plate and visualize the cannabinoid spots as described above.
- Mark the location of each cannabinoid spot on the TLC plate.
- Label each cannabinoid spot with the concentration of the cannabinoid standard solution that was applied to the TLC plate.
The resulting spot chart will serve as a reference for comparing the cannabinoid spots in your experimental sample.
Another way to create a spot chart is to use a TLC scanner. A TLC scanner is a device that can scan the TLC plate and create a digital image of the cannabinoid spots. The digital image can then be used to create a spot chart.
To create a spot chart using a TLC scanner, you will need to:
- Scan the TLC plate using the TLC scanner.
- Save the digital image of the TLC plate to your computer.
- Use a software program to analyze the digital image and identify the cannabinoid spots.
- The software program will typically generate a report that includes the location and intensity of each cannabinoid spot.
- You can use the report to create a spot chart by plotting the location of each cannabinoid spot against the intensity of the spot.
Once you have created a spot chart, you can use it to compare the cannabinoid spots in your experimental sample to the cannabinoid spots in the standard curve. This will allow you to identify the cannabinoids in your sample and to quantitate the amount of each cannabinoid.
Here are some tips for creating a spot chart:
- Use a consistent mobile phase and developing time when creating the spot chart. This will ensure that the cannabinoid spots are reproducible.
- Apply a wide range of concentrations of the cannabinoid standard solution to the TLC plate. This will create a more accurate spot chart.
- Use a densitometer or TLC scanner to measure the intensity of the cannabinoid spots. This will provide you with more accurate results.
- Label the cannabinoid spots on the spot chart with the concentration of the cannabinoid standard solution that was applied to the TLC plate. This will make it easier to compare the cannabinoid spots in your experimental sample to the cannabinoid spots in the standard curve.
…and while the human eye is a incredible sensor, I recommend the electronic method rather than spotting, developing, “photocopying” to transparent media any day.
Edit: FYI, the AI has come pretty close, but really doesn’t understand quite what you’re after. You should however be able to leverage it.
Check @Lincoln20XX’s posts on hplc method dev to get a better understanding of why you need calibrate your measuring devices.