HPLC on flower

I have been researching methods for preparing a sample for HPLC, I have have 2 major questions.

  1. I have read that preparation should be done by freeze drying, grinding, extracting, then filtering out particulates. Is there a way to do this with out the need for a super freeze or liquid nitrogen?

  2. When you finally get to the data, how do you account for the smaller peaks when determining concentration?

I am just learning this stuff and any point in the right direction would be a huge help on these topics.

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Usually there will be a dilution step. I can have my chemist consult with you on sample prep call me at 5303856685

the number is disconnected

Apologies it’s 5303856658

DM me, I can provide HPLC consultation

You don’t need to freeze dry or liquid nitrogen, just need to homogenize the sample to get accurate data

Peaks are identified with reference standards and retention times

To quantify those peaks you need to generate a calibration curve


Does the peak area reduce when testing flower samples? I have a calibration table set up with calibration standards and dilution. I was just thinking that when using flower samples you got less concentration than the actual dry content of the plant.

The peak are is proportional to the concentration of the analyte of interest so if you are testing low potency flower you will see smaller peak area for THca

If you’re testing some really potent indoor flower you will see a much larger peak area for THca

DM me if you have more questions about HPLC

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Just do a QuEChERS method. Easy peasy.

Totally unnecessary for basic sample prep

Just extract in isopropanol or methanol and then filter with syringe and 0.22 micron syringe filter

Quechers is really used for sample prep where pesticides are of interest


Ummmm. Idk how much time you spent in O-chem labs… Its very useful for cannabinoid mass identification… Its what every single ISO lab here in CA uses to prep their samples. :man_facepalming:t5::man_shrugging:t5:

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Doesn’t make it necessary if one is just interested in potency determination


Enjoy the static signal on your readings then :joy:

Sample preparation doesn’t identify mass for you

I think you’re a little confused

Reference standards, retention times, and using a selective wavelength for the analyte of interest are useful for identifying a compound

Integrating the peak area of that compound allows you to deduce concentration

Hplc doesn’t identify mass

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By static I think you mean “noise”

Which isn’t Issuse so long the appropriate wavelength is selected, the proper grade of mobile phase is used, the column is properly equilibriated etc

Things you may know if you’ve taken analytical chemistry

Organic chemistry is a class that talks about how to name compounds, reaction mechanisms, and some basic techniques

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LOL. I have ran NMR for analysis, I think I know how a LC-MS/MS works dawg!

The prep method I posted allows for full extraction of cannabinoids from the biomass, as well as terpene and pesticide extraction. It then involves a LLE (liquid-liquid extraction) step that further ‘isolates’ the compounds you are trying to attempt to analyze.

Just using a solvent to ‘soak’ a plant mass sample wont really exhaustively extract your compounds in total. Much will be left within the biomass that you wont exhaustively extract…

Congrats you ran an NMR!

Now go tell the world young tadpole!

The point I’m trying to make is if potency is the only concern, extracting with an organic solvent is fine.

If you’re wanting to also test for pesticides as well as cannabinoid potency, by all means use quenchers, I don’t really care

If you ran an NMR, doesn’t mean you also inherently understand how LC-Ms/Ms works so it’s a moot point… dawg…

But give yourself a well deserve pat on the back! You’ve done what thousands of other people have done!

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A basic solvent extraction is all that is neccesary analyzing a flower sample. Quechers or liquid to liquid is only needed for non flower sample types in my experience. And I’ve run a HPLC, LCMS and an NMR!



Presumably then, you also understand the difference (other than the $$$$) between using UV vs a Mass Specific detector or a triple quad to detect ones analyte of interest?

OP said nothing about LC-MS/MS.

My guess is they’re doing their due diligence and setting up an HPLC with a DAD for In House analytics

Simple solvent extraction and filtration will get them plenty close enough for that.

I totally agree that running a 3rd party lab, with on the job trained technicians, using a prep kit (Quenchers) as part of your validated method makes great sense.

I also agree with @anon81723932 that it’s not necessary in OP’s case.

@drPaul? @doc_simple?