I mean… I’d be pretty chuffed on some free data lol. Would help me to decide if it was a worthwhile replacement. Does it still give the same resolution between the other cannabinoids? Or specifically d8/d9? (Or I guess maybe you don’t know yet lol)
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Super cool setup from those guys but we took a look and it’s like 2-3k/ month and still 40$ a test from cannid. I like their optimized software and turnkey system but hard to justify that investment financially as opposed to owning a setup.
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Anyone have any expert input on UPLC vs HPLC? I’ve read about the general differences, but is either one particularly better for any reason(s)?
Shorter runs, higher resolution. Core shell particles kinda replaced the traditional HPLC columns pretty much completely 10 years ago and provide similar performance as traditional UHPLC. Phenomenex lead the way with that. These particles have a solid core and are only porous on the surface. This results in less eddy diffusion and therefore better peak shapes and resolution.
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Very interesting. Would you say they require the same level of expertise to operate accurately/correctly?
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Yes, the operation is almost identical
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Good, a final question, if you’ll indulge me, is it then presumed that UPLC results would likely be more accurate than HPLC results, or is that still purely based on method?
I mean i think they’re both plenty accurate. The real benefit of UPLC is shorter times. I think they’re more useful in a situation where you’re trying to do hundreds of samples a day in an analytical lab.
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Ah, when I read this it made me think that meant “better at determining differences in peaks” which I interpreted as more accurate.
Well that could be the case in situations of super close peaks but good HPLC methods shouldn’t run into that much
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Ah ok I see what you are saying now. Out of curiosity, how big is the MS error normally and how big can it get? Is there a bias to over reporting or under?
Usually an RSD of about 10-15% is acceptable in MS. With an FID or UV this should be way under 2%. Not to say that you will never haver better RSD’s with MS, but there is inherently more variation.
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Not really, both methods should get you an RSD < 2% but the HPLC run would be 30 min and an UHPLC would be 5 min or so. Initially the idea came from Waters and they released the UPLC. The concept was that by having smaller particles in your column, you have less eddy diffusion. However, if you have smaller particles, you get much more back pressure, so Waters just cranked up the pressure. But then the core particles came out, which meant you also had less eddy diffusion as the solvent can’t penetrate to the core but you can keep the particles larger and have less back pressure. That is kinda the idea. But yeah, with core shell particles you can use normal HPLC pressure and have UPLC resolution. It’s kind made the concept of ultra high pressures obsolete. And because you can have higher flowrates due to less back pressure, it all kinda ends up being the same.
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This depend on what kind of analyses you intend to do for the most part.
I would rank the choice in the same order as you listed it.
To my opinion HPLC presents much less advantages than GC.
The most cited advantage of the HPLC is the fact that differentiation between acid and non acid cannabinoids is more straightforward than with GC. This is only a true advantage if you intend to focus on acid cannabinoids or intermediate decarboxylation levels on a regular basis. Which still poses the issue of calibration of each individual acid/non acid ones…
I think the main advantages of HPLC is rather the significantly lower detection limits which can be achieved, which are necessary for analysis of trace delta 9 is edibles for instance, at ppm levels.
I believe GC present much more advantages, especially GC-FID.
GC is generally much cheaper, more robust, easier to maintain, more stable and also much more modular. The basic technology has not changed much since decades. Depending on set-up, it can be used for potency tests, terpenes analysis, residual solvents, even other components. Calibration is more straightforward. There are still many old units around running well. One can’t tell so dealing with HPLCs.
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As far as interpreting results does the gc fid still provide the most simplicity?
As far as interpreting results FID is the least informative because co-eluting peaks can’t be differentiated whatsoever.
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When just looking at peaks does thc co-elute with CBD or just thc isomers with a gc fid?
Gc-fid reads basic stuff easily (major cannabinoids). When you’re starting to deal with some isomers it loses flexibility compared to an HPLC
Yes. GC-FID is the most straightforward for interpreting the data, the simplest.
It give you a “carbon number”, which is quite proportional to the molecular wight of the compounds were are looking at. This makes calibration also more straightforward.
It does however not tell you what the compound is.
Only the retention time (provided you have a reference for matching it) gives you an indication. Against there, it is not a straight an unambiguous identification, since other compound(s) could have the same retention times. But if you now your samples, and using a well set method, this is not an issue. Becomes an issue only with unknown samples.
This is independant on the the chromatographic method (GC vs HPLC) and detection method. This only depends on the type/length of column you use, the eluent, on the temperature (or solvent, pH etc…) program, and flows which are employed. The goal in setting a consistent method is too have a sufficient invidiual separation of the analyte(s) of interest from other componants.
What advantage(s) would HPLC bring in such situation ?
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