I work for an in house testing lab at an extraction facility in NY. We recently acquired a Waters ULPC e2695, PDA 2998, and QDa detector.
I have been running an Agilent HPLC for potency testing. Besides potency, what exactly can this machine do for us? Potency obviously, but is this achine more accurate? what other tests will this allow us to do, I assume heavy metals? what about terps, heavy metals, pesticides?
I’ve been reading up on mass spectrometry and the PDA but if anybody can point me in the right direction that would be great, thank you
I have never used a QDa , but from what I am reading i think it is a single quad mass spec ?
From my experience MSDs are not going to be as consistent as UV detectors. The benefit of MSDs is lower sensitivity. Which also means you will need to dilute your samples to a much lower concentration compared to UV analysis. The choice is to either use a shitload of extra solvent or to perform serial dilutions. And serial dilutions will add more uncertainty/variation in your results.
Heavy metals are not typically analyzed via LC, but rather ICP, flame AA, or some other elemental analysis method
Terpenes are a possibility, but most labs choose GC for volatiles / semi volatiles
Pesticides are also a possibility, though I don’t know how low of concentrations you are required / want to see down to. As a single quad MS is not going to be able to achieve the same level as a triple quad MS
I think this system is mostly designed to be used as a UV , with the sample stream flowing to your QDa after it flows through your UV , so you can have additional mass data to help confirm analyte ID and/or characterize unknowns
The QDa is essentially mass spec lite. You can definitely use it for quantification purposes. It’s not as robust as a MS/MS but it should still allow you to get some basic separation data and be able to quantify compounds.
Accuracy and precision are really going to be determined on how well the machine is kept up and calibrated. It’s an instrument built for analytical quantification/qualification, so it is going to be able to BE accurate and precise, but how accurate and precise is going to be up to you. If you run concentrations outside your calibration curve or don’t make sure things like injection volume are calibrated properly, then even systems built for hyper accuracy or precision can yield inaccurate and imprecise results.
A PDA is just a UV based detector, so it’s going to do exactly what your agilent can do.
As for what other tests you can do? Heavy metals is going to require ICP-MS for analysis, so that’s out. Terps and pesticides you can do, sure, you just need to make sure you have low enough sensitivity to be able to detect them with your qda. This is where your calibration is important and finding the concentration it can detect. You should be able to detect and potentially quantify at sub 1ppm in concentration. Terps will probably be better on a standard GC or headspace GC depending on volatility, but you should still be able to get some level of analysis done with terps, especially if this is all in-house for your own knowledge. It could be a good tool to leverage knowing it may not give you the full picture.
Basically, at the end of the day, it’s going to do exactly what your current agilent system can do with a few minor upgrades to let you see down to probably ~1ppm concentrations and maybe give you a little more flexibility in analyte detection.
The other benefit, if it’s actually built as a UPLC, to me that implies it has a pump that can generally handle higher pressure, which means you can run UPLC designed columns (usually much shorter), which should allow you to cut your run times down significantly while yielding the same resolution, accuracy and precision.
I think the best way this machine will improve your work is going to be to move your methods over from the agilent and optimize them for shorter run times with UPLC designed higher pressure columns (typically can handle up to 2.5x the pressure). If your potency run normally takes 30 minutes on a standard 150 - 250mm column, columns run under higher pressure are generally 50 - 100mm long and you can cut those run times in half at least, sometimes faster if you’re doing something relatively simple like a potency test.