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gently caress mass spectrometers, and every person who has designed current mass spectrometer control software should be beaten to death with an iPad. Hi, I'm Lunar (Dr. Lunar if you're nasty), and I work in a hospital as a trainee clinical scientist.
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Jul 21, 2021 13:49
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| # ¿ May 12, 2024 06:16 |
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mass spec control software reviews: Waters: Con: Why are there four different windows I need to coordinate across? why can I operate the electronics and gas, but not the source pressure and fluidics, from the master panel? Why can I change flow rate and composition, but not load the method I've selected? please export data as a file, not a folder, you're a pain to get into MzMine. Pro: can copy/paste into the sample list, can use "fill down" and "fill series" to not have to type out every single thing yourself. Analysis and export not that painful. ThermoFisher: Con: ugly as a student's first year C# project, frequently fails to connect to MS. Some of the older versions seem to run on goddamn telnet. Hardcoded filepaths make setting up a right pain Pro: export into an industry standard file format means you can actually backup your project Sciex: Con: your analysis module is terrible. Click on the axises to zoom in on the chromatogram. Zoom does not persist, even inside the same sample. Pro: shinier machine?
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Jul 22, 2021 14:02
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MS re-tuning works a lot better a) using combined rather than infusion mode, which produces weird peaks that just constantly shift b) when actually infusing, not purging the reservoir, then forgetting to re-enable flow into the MS Still working on getting my sea legs - what is and isn't a peak seems kinda fuzzy and I panic when I see a sea of ever-shifting red bullshit, but at least I did get a signal for the expected precursor peak, fixed one product ion at an m/z closer to predicted, and found another product close to where it's predicted to be, so this assay might actually get off the ground. RIP to all the candidates that did not make it in the matrix (the joy of faecal proteomics). I should have reached out to the lab's university contact immediately - apparently, you don't go into matrix with any fewer than 60 transitions or so, since 99% of transitions working fine in pure (digested) protein will not work in matrix. for pride month, i will remove the m from masshunter
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Jul 28, 2021 09:43
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We might Intranet the mass spec machines. There’s a piece of software called Specbase promising to automatically extract performance data. If it works, we would not have to put QC levels and back pressure manually into a billion spreadsheets.
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Aug 6, 2021 08:08
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The integra is both saving us tons of time on 96-well plate Vit D preps, and also a massive pain in the rear end. Aparently you have to program it using that little iPod they stapled to it as a user interface. Also we need to do a solvent exchange on our spicier preps so we don't melt their internal o-rings.
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Aug 22, 2021 17:32
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Johnny Truant posted:I had a master's in biotech ask me if they needed separate pipette tips for different samples when processing blood. The hospital I trained at used expensive positive displacement pipette tips to get 20/100/150 μL of patient samples into 96 well plates, since precision was a key requirement. To reduce tip waste (and costs), they implemented a protocol of rinsing the tip in 5ml tubes of MilliQ water, then methanol, then a second 5ml aliquot of MilliQ water between each sample. The rinse protocol was validated by testing the second MilliQ water with the triple-quad mass spec, and that didn't find any analyte - so apparently that worked. However, I get the feeling this story didn't feature positive displacement tips. I sure as hell wouldn't try that with an air displacement Gilson. crabrock posted:if you had problems with RNA in their stuff it's probably because you thought too hard about the RNA, and it degraded out of shame. Please, no you're giving me flashbacks to my PhD. I had to get a 1mm slice of deep-frozen cardiac atrium, move it to the phenol/chloroform and get it ready for bead beating in like 30 seconds before it thawed too much. You haul your rear end off, you try not to get cancer from the phenol/chloroform, and your RIN still looks like arse. Lunar Suite fucked around with this message at 10:46 on Jun 23, 2023 |
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Jun 23, 2023 10:41
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Again: They ran the second water tube through the mass spec and detected nothing. The protocol was validated. I was shocked at first too, but they have evidence the method is sound, and the regulatory agencies didn't flag it on SOP review either.CuddleCryptid posted:Did they have you blow on them to make sure they were dry before using them again?
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Jun 23, 2023 13:21
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mycomancy posted:Also what on earth requires precision at 20 μL that a non-adjustable pipette can't deliver? Are you counting individual heme molecules in blood? Immunosuppressant monitoring by mass spec; you add 150 μL of internal standard and 50 μL Zinc Sulfate to dilute and shoot. If you're imprecise, the patient's transplant may fail. RadioPassive posted:Did they validate the volume precision after cleaning? Yes actually, and because the 20 μL tips were causing issues (blood leaking past the positive displacement plunger in some cases), they switched to 50 μL tips out of caution. EQA performance and QC are running fine Assuming they legitimately did put the second wash water through the Mass Spec and didn't find levels of analyte over the LoD, isn't that sufficient evidence to prove there's no carryover able to affect assay results? I believe carryover studies were also run (high-concentration samples before analyte-free matrix). This country's healthcare system is held together by spit and prayer. Rinsing the positive displacement tips makes a massive difference for budget (and saves plastic waste). Lunar Suite fucked around with this message at 16:39 on Jun 23, 2023 |
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Jun 23, 2023 15:36
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RadioPassive posted:I’m just floored that test tubes, MilliQ, methanol, MS time, and a validation of the process were somehow cheaper than buying fresh tips. Welcome to working in the NHS! If it makes you feel any better, it also cuts down on plastic waste... probably (the test tubes are also plastic).
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Jun 26, 2023 09:20
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Guess they didn't have remote temperature monitoring. The lab in which I did my PhD and the hospital I trained in all had external third-party sensors capable of texting/calling supervisors and maintenance staff if the temperature rose. Some even had a  . Is that not a thing in the US?
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Jun 27, 2023 09:24
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| # ¿ May 12, 2024 06:16 |
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Mustached Demon posted:If you have enough chemistry background, I highly recommend the semiconductor industry. Everything uses HF so you still get the thrill of working with materials that prefer dead humans over the living. What's wrong with working with something that'll rip the calcium from your blood and bones until your heart stops? For other Fun Compounds I highly recommend Derek Lowe's sadly discontinued Things I Won't Work With
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Jun 28, 2023 08:49
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