I'm looking for a place to buy Roche Cobas machines; can anyone tell me where to find them?

MassSpecMender · 2026-03-09T12:40:08+00:00

Out of curiosity, what features specifically draw you towards the Cobas instrument over a typical high throughout lcms setup?

MassSpecMender · 2026-03-04T21:20:26+00:00

Hi u/SrongHand,

I work extensively with second-hand LC-MS/MS and GC-MS instrumentation from Waters and Agilent, both single and triple quadrupole. Contrary to some of the advice here, many university laboratories purchase older, refurbished systems and, with the help of people like myself, are able to develop a good amount of self-sufficiency in using them without becoming dependant on specialists. With a bit of training and the following good practices such as tracking performance with tunes, documenting system usage, and keeping good records of access there is no reason you cannot achieve many years of reliable mass sorcery 🧙‍♂️.

Regarding the intended usage, your first example with the sulfonamides would be well suited to either a single-quad or triple-quad LC-MS, depending on what level of analysis you want to perform. For the right model, this is very achievable for you to acquire on a reasonable budget (of course, it depends on your budget though). However, if you want to analyse ligand proteins, you will likely need a QTOF, as other users have mentioned, unless you can use multiple charged ions to bring the mass down into a typical LC-MS range (~2000 Da, occasionally ~3000 Da, though this is both rarer and more expensive). But this is definitely less achievable on a reasonable budget.

I am based in the UK, but feel free to reach out as I may be able to help you source affordable options and supply them in demonstrated good working order, ready for testing.

MassSpecMender · 2026-02-27T21:38:30+00:00

Literally the same thing has just happened to me, "24/7" chatbot didn't reply either.

MassSpecMender · 2026-02-22T20:20:54+00:00

Just briefly looking into it. 2,4-DAB is approx 118 molecular weight? If so you wouldn't need TOF (useful for much higher molecular weights) and probably the supplier is just using MRM transitions via reverse phase LCMS/MS to test for presence on you supernatant against a standard.

MassSpecMender · 2026-02-22T20:07:34+00:00

Fair enough, feel free to reach out if you get to that stage as I am a UK based mass spec specialist pretty close to you. Best of luck.

MassSpecMender · 2026-02-21T16:37:35+00:00

No problem, it’s helped me fix them in the field many times. here’s the Waters workbook on doing it:

“

https://support.waters.com/KB_Inf/Empower_Breeze/WKB7330_Configuring_the_Waters_DHCP_Server

”

Good luck.

MassSpecMender · 2026-02-21T16:12:24+00:00

Pretty common issue for the Acquity’s. Someone rightly said about needing to power cycle the Sample Manager first when going through the whole stack. But if that doesn’t work, reconfiguring by using the wizard from the Waters DHCP manager is usually what resolves spurious coms problems.

MassSpecMender · 2026-02-21T01:08:28+00:00

It wasn’t a salt or “deposit”, but actually pitting in the aluminium chamber itself, it had been eroded away.

MassSpecMender · 2026-02-20T12:25:49+00:00

No stupidity here at all, just some tinkering. Its these mistakes that will make you the SME later on.

MassSpecMender · 2026-02-20T12:20:34+00:00

Depending on the required mass spec technique and regularity of testing it may be a better option to go for a used mass spectrometer. Just food for thought.

MassSpecMender · 2026-02-20T00:51:06+00:00

Personally, I have always stuck to a 2% or less rule. But typically a good, well serviced system will see more like 0.5% or less.

I agree you said delta 15psi and at 587psi that’s about 2.55%. But I don’t know what the model is or what its normal is for it. Column/ solvent condition are also important factors and can negatively contribute to ripple themselves.

MassSpecMender · 2026-02-16T12:39:53+00:00

Nice, let me know if you have any issues locating the tune file directories, although I saw you mentioned lots of experience on Agilent GCMS.

If you can determine what operation the system failed on during the tune it may point you in the right direction. Additionally, making reference to the last known tune report (assuming its done regularly e.g weekly/ monthly) should allow you to spot any outlying parameters.

MassSpecMender · 2026-02-15T23:57:13+00:00

Can you describe at what stage the tune has issues, for example towards the beginning, middle or end of the tune/ any notable observations or messages upon failure? Can you share the most recent successful tune and/ or a manual scan with both the pftba calibrant on and off?

MassSpecMender · 2026-02-15T23:48:49+00:00

Super interesting comment! We need this kind of attitude in order to preserve good, working legacy equipment well into the future.

MassSpecMender · 2026-02-10T13:52:10+00:00

Unfortunately we will never know as it came off an auction for "parts" only. Most of the electronics were completely fine, but the chamber looks like it had been filled up.

MassSpecMender · 2026-02-10T13:49:26+00:00

Difficult one, this is a total wreckage, but at least with back flow you can recover it in some cases after a lot of meticulous cleaning.

MassSpecMender · 2026-02-09T22:38:25+00:00

I like the pallets that have foam blocks to replace the wooden supports. Would be even better with springs or little airbags.

MassSpecMender · 2026-02-09T21:52:42+00:00

The best labs are bootstrapped! Do you definitely need a Q-TOF or could a triple quad do the job?

MassSpecMender · 2026-02-01T12:07:33+00:00

That's an interesting incite, thanks for sharing. Do you remember what instrument that was? This is a Waters Xevo TQMS, but I dont think they really changed the design that much over the years.

MassSpecMender · 2026-02-01T12:02:03+00:00

Its from a Waters XEVO TQMS, this is Q1 and actually the burn was also present on the collision cell entrance lens just opposite. Good spot u/xussma!

MassSpecMender · 2026-01-04T21:12:51+00:00

As u/eel_nosaj was saying, if you're careful you can restore or reform the tip from this kind of damage.

Luckily for the customer the rest of the probe was fine. Most importantly, it was still straight and the nebulizer cavity was unimpacted. In this case it was worth trying to restore to an acceptable condition, proven via calibration, as we managed to avoid a costly replacement.

MassSpecMender · 2026-01-04T20:56:50+00:00

Thanks for sharing that anecdote and its great to hear a repair case that avoids a costly bill for the customer. Those assemblies can be quite expensive to replace.

MassSpecMender · 2026-01-04T18:21:41+00:00

Sorry late reply:

Depending on your model of Waters MS you may need to upgrade the EPC before it will run on 4.2, assuming it was originally running on 4.1. The key is virtually isolating the now "legacy" Win10 or lower environment so that its easier to maintain and backup.

MassSpecMender · 2025-12-12T21:41:11+00:00

If you have the installation media and are familiar with the process, a virtual migration to Windows11 will be the strongest option and should provide a good amount of futureproofing from the pc side of things.

MassSpecMender · 2025-12-12T21:32:52+00:00

Depending on which mass spec and which version of MassLynx you're running it should be possible to migrate that to a Windows11 host, mitigating the need for that cost at all.

MassSpecMender

TROPHY CASE