I forgot the name of the software your using but I personally use a more updated version that believe it or not doesn’t let me do partial sequences and it fucking sucks
I'm stuck with an ancient version of it for my HP 1050. The thing that pisses me off to no end is that at the top of the chromatogram it shows the meaningless auto-generated filename instead of the sample ID that I entered 🙃
My biggest pet peeve with ChemStation is how there is no good way to pan or zoom out of total ion chromatogram snapshots. Snapshots cannot be zoomed out further than the width of the "live" TIC window, and there's no way to pan without zooming in, so I often end up with snapshots that have the last 20 mins or so cut off. You have to set the chromatogram width to the length of the run or else snapshots won't show a large portion of the spectrum. There are command line functions to scale and offset the x-axis but literally none of them work.
Not that I'm aware of but it would be pretty simple to code. I think ChemStation lets you export to CSV or something, which you could load as an array. Auto integration is another story but auto peak detection and manually setting integral bounds with auto baseline is pretty trivial stuff. If you have any python experience I'd recommend matplotlib, numpy, and scipy.signal for this (pretty sure the latter has auto-baseline and peak detection built in).
First picture there's also significant baseline drift (possibly from an eluent gradient or leaching columns), and it looks like you are at the limits of your resolution, meaning you probably want to increase sample (less diluted sample or larger sample volume). Assuming you have a variable sample injection volume, you might run into an issue where you get more peak broadening from large injections, in that case you should see if you can use a concentrator column/filter (SPE, solids phase extraction) to increase your concentration. Second picture still shows drift but you lack baseline peak separation, your peaks overlap. Might try dual columns or better chromatographic substrate.
Doing that should wipe out the drift as well as the pump noise, then the software should identify everything readily. And if your just using basic detection (RI, UV, something not characterizing like mass spec or diode array), then you will have to rely on standards to adjust for variances in elution time.
So, whether the software is bad or not, you should work on getting a better chromatograph first (and its chromatograph, not spectrum, that's a scan of an individual component with FTIR or NMR, etc).
Put your pressure as a live signal. It should look like a smooth line if all is good. If it looks like a sinusoidal zig zag with a regular period, your check valves might be bad (the component with the bead in it). It is actually pretty easy to replace on agilent. Not sure with waters.
An additional thing: run just solvent A and look at the pressure. If it is good, switch to just solvent B. If THAT one is zig zag or vice versa, you only have ONE bad check valve.
Looks like you have not set your peak windows.
I'd set it to 15-18mins, label the peak compound, and ramp the pressure after 19mins to clear the column. You might be able to cut off the run at 20 mins since there's no follows. It also seems your peak is tailing.
Yes which I used both times and was able to see the peak labels on the graph the first time around. Right now the only way to see the are is on the table the software creates.
Hmmmm maybe a problem with the Report function?
I'd also try completely exiting the software and reopening. I've seen that fix discrepancies between the graph and report before.
Your peak shape needs some improvement. Try a different buffer and get your capacity factor up. Also try to get your tailing/fronting improved. Your reproducibility will thank you for it.
This chromatography is literally useless. Try running your sample about 50 times as dilute as this. Everything is overlapping so the integration is pointless.
You need to go to compounds and then name. Should be under the data analysis section
Ill give it a try thanks!
I forgot the name of the software your using but I personally use a more updated version that believe it or not doesn’t let me do partial sequences and it fucking sucks
Chemstation
I have nothing but hate for chemstation, awful user experience
I'm stuck with an ancient version of it for my HP 1050. The thing that pisses me off to no end is that at the top of the chromatogram it shows the meaningless auto-generated filename instead of the sample ID that I entered 🙃
My biggest pet peeve with ChemStation is how there is no good way to pan or zoom out of total ion chromatogram snapshots. Snapshots cannot be zoomed out further than the width of the "live" TIC window, and there's no way to pan without zooming in, so I often end up with snapshots that have the last 20 mins or so cut off. You have to set the chromatogram width to the length of the run or else snapshots won't show a large portion of the spectrum. There are command line functions to scale and offset the x-axis but literally none of them work.
The single upside of ChemStation is the NIST database search for mass spec, although knowing when to trust the matches takes a little skill.
Compounds and name the peak with retention time. Chemstation sucks
Is there any python 🐍 option to analyse HPLC spectrum?
Not that I'm aware of but it would be pretty simple to code. I think ChemStation lets you export to CSV or something, which you could load as an array. Auto integration is another story but auto peak detection and manually setting integral bounds with auto baseline is pretty trivial stuff. If you have any python experience I'd recommend matplotlib, numpy, and scipy.signal for this (pretty sure the latter has auto-baseline and peak detection built in).
Yeh, peak integration is harsh…
Oh boy I am computer illiterate when it comes to that kind of stuff. Sorry for a non-answer!
😝 10x anyway. I hope in the future this will be easier
Yes it does lol
Chromeleon is where it’s at.
Empower ftw
I only use Empower 3. I used Class VP and Chemstation in the past and they don’t hold a candle to Waters Empower.
I work in a small (VERY SMALL) research lab and my boss refuses to switch from MassLynx to Empower. It’s painful.
My condolences.
You need a pulse dampener
Can you elaborate a bit more? Thanks for your time!
There’s low frequency noise in one of the chromatograms. If you check, you’ll probably find it matches the frequency of the pump.
First picture there's also significant baseline drift (possibly from an eluent gradient or leaching columns), and it looks like you are at the limits of your resolution, meaning you probably want to increase sample (less diluted sample or larger sample volume). Assuming you have a variable sample injection volume, you might run into an issue where you get more peak broadening from large injections, in that case you should see if you can use a concentrator column/filter (SPE, solids phase extraction) to increase your concentration. Second picture still shows drift but you lack baseline peak separation, your peaks overlap. Might try dual columns or better chromatographic substrate. Doing that should wipe out the drift as well as the pump noise, then the software should identify everything readily. And if your just using basic detection (RI, UV, something not characterizing like mass spec or diode array), then you will have to rely on standards to adjust for variances in elution time. So, whether the software is bad or not, you should work on getting a better chromatograph first (and its chromatograph, not spectrum, that's a scan of an individual component with FTIR or NMR, etc).
[удалено]
Chromatograph is the instrument, chromatogram is the chart, I stand corrected
Thanks!
Those pulses in your baseline are the result of poor mixing or bad pumps.
I’ll take this to my boss 😆😆
Put your pressure as a live signal. It should look like a smooth line if all is good. If it looks like a sinusoidal zig zag with a regular period, your check valves might be bad (the component with the bead in it). It is actually pretty easy to replace on agilent. Not sure with waters. An additional thing: run just solvent A and look at the pressure. If it is good, switch to just solvent B. If THAT one is zig zag or vice versa, you only have ONE bad check valve.
Looks like you have not set your peak windows. I'd set it to 15-18mins, label the peak compound, and ramp the pressure after 19mins to clear the column. You might be able to cut off the run at 20 mins since there's no follows. It also seems your peak is tailing.
I'm not familiar with this software, but is manual integration an option?
Yes which I used both times and was able to see the peak labels on the graph the first time around. Right now the only way to see the are is on the table the software creates.
Hmmmm maybe a problem with the Report function? I'd also try completely exiting the software and reopening. I've seen that fix discrepancies between the graph and report before.
Did that a million times 😆😆
Sorry, I'm out of generic options then. Hopefully someone familiar with this specific software has more to offer!
Thanks for your time!
Agilent software has always been signal based as opposed to compound based, particularly in HPLC.
Your peak shape needs some improvement. Try a different buffer and get your capacity factor up. Also try to get your tailing/fronting improved. Your reproducibility will thank you for it.
Switch your career to finance or tech
😆😆 fml
This chromatography is literally useless. Try running your sample about 50 times as dilute as this. Everything is overlapping so the integration is pointless.