- by /u/vaquerosupremoHello all, I am a final year PhD student in synthetic biology/molecular biology currently writing my thesis. I have genetically engineered cells to make novel therapeutics and sent samples to a company for running on LC-MS. I have the MS data and have been using MS-DIAL to search for my compounds of interest. From the MS DIAL results I have peaks which are consistent with the positive control which aren't present in my negative control – therefore I believe my cells are making my product. But I was wondering how to present this in a PhD thesis? I am not […]
- by /u/OwlScary4912I test drinking water and use a NexION 350 and a NexION 1100. The 350 works great but it’s old and the 1100 mostly work fine but the lead numbers all around drop throughout a run. It can fall sometimes -.300ug/l between calibration checks from the start of the day to the end of the day. It also starts out lower with the same calibration check when compared to the 350. We’ve tried everything and literally nothing seems to work. Any help would be be amazing would love to figure this out before the 350 completely shuts down. Doesn’t matter […]
- by /u/Top_Occasion_1467My lab has a Waters QTOF with Lenovo P520 workstation. I installed an Nvidia RTX Pro 4500 GPU for new the GPU Enabled Peak Detection feature in Waters_Connect. There is about 70% reduction in peak processing time, which is in line with the advertised result. Great. However, the GPU and CPU are still underutilized with the new algorithm. Peaked at only mid-30% for both. Do you have similar observations? I am running the software and database on NVME SSDs and there are ample RAM left. So, i dont think there is a bottleneck there. The software only process 4 samples […]
- by /u/Training_Pangolin177The instrument was idling fine with no reading for turbo pump 1 iongauge but good reading for turbopump 2. When trying to restart the mass spec, the status on the mass spec panel keep flashing oringe and both ion gauge in orginge color. On the computer, mass spec or diagnosis is offline and no connection to the mass spec or configuraton can be made and mass hunter won't open. Doesn this mean some board on the mass spec needs to be replaced? If so whicn one is it? Thank you. submitted by /u/Training_Pangolin177 [link] [comments]
- by /u/Usual-University-228submitted by /u/Usual-University-228 [link] [comments]
- by /u/mai1595What QC standards do you use for the system suitability testing of your Mass Specs at your lab?? Do you use labeled or unlabelled standards, and do you have preferred compounds for HILIC and C18 columns? submitted by /u/mai1595 [link] [comments]
- by /u/NoAnnual7603Hello everyone, We’ve been using a Waters Synapt XS since 2022 for untargeted metabolomics. In our opinion, the instrument is a lemon and has suffered several total failures since we purchased it; among other things, two turbos have crashed, several cables inside the instrument have loose connections, and we recently discovered that the DRE lens was not soldered properly (and therefore likely did not function correctly). We have also observed an excessively rapid rise in detector voltage since we started using the instrument, which cannot be explained by usage (we do not use the instrument very frequently, and the samples […]
- by /u/anasmrait12Hello everyone, I am analyzing mercury (Hg) in water and food samples using Cold Vapor AAS with a Flow Injection System (FIAS/Hydride Generation accessory). Recently, I have been obtaining unexpectedly high mercury results, not only in my samples but also in a certified reference material (LGC CRM). This makes me suspect a problem related to contamination, memory effects, calibration, or solution stability. My Question is: Do you add any stabilizer to mercury standards or sample solutions (for example KMnO₄, HNO₃, K₂Cr₂O₇, Au, etc.)? Any advice or troubleshooting suggestions would be greatly appreciated. Thank you! submitted by /u/anasmrait12 [link] [comments]
- by /u/drphilthy_2469Any way to access the Marinlit database for matches through vendor software and workflows that include library searches or is it all manual from a curated short list? Would love to hear if you have experience. Thank you. submitted by /u/drphilthy_2469 [link] [comments]
- by /u/BizMaker_2504submitted by /u/BizMaker_2504 [link] [comments]
- by /u/SyllabubDirect2476I'm analyzing urban atmospheric filter extracts by GC×GC-TOF-MS. The chromatograms look reasonable at lower temperatures, but at higher temperatures a large unresolved hump appears. The dominant compounds seem to be alkanes. My goal is to characterize the samples as comprehensively as possible, ideally assigning as many detectable peaks/components as I can rather than treating the hump as a bulk feature. One suggestion I received was to switch to a more nonpolar 1D column with a thicker film, but I'm already using a DB-5ms column. Before I start changing hardware, I'd like to ask: What approaches have you found most effective […]
- by /u/Mean_Dragonfly_3068Hi all, I'm curious how people are approaching untargeted PTM and proteoform discovery, specifically without enrichment. Most workflows I see assume phospho/glyco enrichment up front, but I'm interested in casting a wide net across PTM types in a single run and seeing what falls out, rather than going in with a hypothesis. A few things I keep going back and forth on: DIA vs DDA: The trade-offs are known. Has anyone landed firmly on one for discovery-mode PTM work? Software/ platform: What are you running and what's the setup? What have you tried? Yield: How many PTM types were you […]
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