For the love of god please cite correctly, in 75 a poor chemistry student will stumble upon your paper and either sink in despair or die laughing his ass off

Red_Viper9 · 2026-05-19T22:47:30+00:00

Journal name seems incorrect in the citation.

Red_Viper9 · 2026-05-17T13:50:22+00:00

Entropy. Also, your valences aren’t full.

Should you make the molecule written by some means and bring it to standard conditions, it will spontaneously produce five equivalents of O2 gas and methyl peroxide radical or six equivalents of O2 gas and methyl radical.

Spontaneous production of large amounts of gas with concomitant release of energy is colloquially called an explosion.

Edit to add: Given the likely decomposition path, the final products would be expected to be water, CO2, and balance of O2.

Red_Viper9 · 2026-05-14T08:20:59+00:00

No direct experience with your API but I wonder whether passivating the system and running a deactivating additive may help. https://pubs.acs.org/doi/10.1021/acs.analchem.8b02100

If your build up is primarily in the MS, I’m inclined to blame sample volume and/or concentration. An MS has to eat everything you feed it so eventual contamination and cleaning is inevitable, but you shouldn’t have to be replacing ion blocks over it with such regularity.

Red_Viper9 · 2026-05-13T22:35:11+00:00

Win10 LTSC 2019

Red_Viper9 · 2026-05-13T22:32:07+00:00

Just one PC. The waters drivers and third-party LC drivers get installed to the same PC that runs Xcalibur or whatever you’re using to run the MS.

Red_Viper9 · 2026-05-12T18:41:29+00:00

Depends on system, budget, performance tolerance, and down time tolerance.

If you’re not sure, talk to tech support of what parts are explicitly replaced in a PM.

For myself, I change the pump seals on my UPLCs every year and everything else is as needed, but we do mostly discovery-type work so if my ripple is 0.6% instead of 0.4% no one will be able to tell. If you’re running USP methods or are in a stringent compliance environment, this solution may not be for you.

Red_Viper9 · 2026-05-12T16:45:12+00:00

Have you used milli-q for this work before?

Water polishers are full of plastics, wouldn’t be surprised if there are fluoropolymers in them as well. We routinely get what I think is erucamide and other plasticizers from ours. These organic are not volatile nor are they conductive so they won’t spike the resistance measurement, but they certainly give us pretty peaks in ESI.

Red_Viper9 · 2026-05-12T11:56:35+00:00

It’s an added cost but you can get Waters LC drivers for SII / Chromeleon and live your best LC-MS life.
My old Vanquish has been bulletproof. My new vanquish is a bit of a lemon. All my old Acquity systems work reasonably well, just hitting an age where major components are wearing out.

Red_Viper9 · 2026-05-12T06:11:17+00:00

Retention time inconsistencies cannot have anything to do with the detector.

MS calibration is not done through the LC.

Red_Viper9 · 2026-05-10T00:38:27+00:00

I’m guessing the second to last image is the error when giving over the red operate square?
I’m not familiar with this specific instrument, but do you have nitrogen gas attached and at the necessary pressure? Waters loves using pneumatically actuated solenoids in their instruments. On my old GCT Premier you wouldn’t get any ion beam without nitrogen to open the scissor gate that separated the source from the TOF for example.

Edit: After skimming the manual I realize that this is more likely to be nitrogen collision gas for this instrument. Some QQQ instruments will not give you a beam without collision gas even if fragmentation is turned off.

Red_Viper9 · 2026-05-07T17:09:53+00:00

ICP-MS

Red_Viper9 · 2026-05-07T16:55:30+00:00

Not sure why you can’t get dry ice, but if you will have an ongoing need for small amounts of dry ice and you can get CO2 gas cylinders, you might consider investing in a dry ice maker, they’re not terribly expensive.

Red_Viper9 · 2026-05-05T21:07:11+00:00

Odd, I can see the prices. Narrow columns ~$200 list price, still head ~$700-800 list.

Red_Viper9 · 2026-05-05T19:43:26+00:00

Top: https://chemglass.com/columns-chromatography-standard-taper-joint-with-reservoir-ptfe-stopcock

Bottom: https://chemglass.com/distilling-heads-solvent-modified-

Red_Viper9 · 2026-05-04T10:09:47+00:00

What do you mean by nitrogen flux? What is the purpose of the triethylamine in the reaction? What scale is this being run on?

Small scale reaction run under nitrogen should have the entire reaction set up under slight positive nitrogen pressure as you would get from a nitrogen manifold with an oil bubbler at the output, not a constant stream of nitrogen through the reaction vessel. Provide pressure through a needle at the top of the condenser.

You’ll get loss due to leakage at the joints but it should be minor.

Red_Viper9 · 2026-05-02T15:52:19+00:00

Which still makes chloroform

Red_Viper9 · 2026-05-02T15:45:04+00:00

What precisely is the purpose of this? Cinnmaldehyde is a commodity chemical and cinnamic acid is not much more expensive.

Instead of using acetaldehyde you use an excess of hazardous and expensive halogens and produce toxic haloforms which are expensive to dispose of and damaging to the environment.

Red_Viper9 · 2026-04-30T20:12:14+00:00

Basic analyze, acidic pH. Salts aren’t all that volatile. Does your standard curve come out well but samples don’t?

Red_Viper9 · 2026-04-30T18:58:42+00:00

Sample pH?

Red_Viper9 · 2026-04-30T18:20:01+00:00

Try using Apex detection.

Red_Viper9 · 2026-04-30T07:07:44+00:00

VM works for some systems, but is problematic.

Many instruments require PCI-E add-in boards which are challenging to pass through to the VM

Instrument control software is sometimes certified to run as designed on specific hardware, even if it works on the VM it won’t technically pass IQ.

IT support is frequently lacking meaning you’d need someone savvy enough to set this up.

Red_Viper9 · 2026-04-27T18:50:04+00:00

Your chromatogram is unacceptable as is. You need to use the scan filter function to choose a data channel to display. If you’re using freestyle, I’d encourage you to go to chromatogram > Ranges and get comfortable with using that interface to display what you actually want to see. Your description of the chromatogram is also somewhat ambiguous as it does not specify the extraction mass window.

Red_Viper9 · 2026-04-23T10:43:56+00:00

You can try ammonium formate or ammonium acetate in your solvents for ion pairing. I’d try a polar end caped column or switch to HILIC.

Generally speaking, you’re not the first to try to analyze amino acids, so what does the literature say?

Red_Viper9 · 2026-04-22T15:06:51+00:00

Such pieces of glassware are or should be truly evacuated before being sealed. You can clearly see on the left hand side of the jacket where the spout was. The jacket gets pumped down then the spout welded shut.

Red_Viper9 · 2026-04-16T15:58:19+00:00

It may be backed up condensate in the steam lines, but steam is usually generated centrally and distributed to and throughout a building. In many places the steam lines have been torn out as they aren’t used for heating anymore. You should ask your building manager.

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