- by /u/MobilePhase1987Hello I am have issues developing an MRM method for pesticide testing, mainly with one compound: 4,4'-DDT. I do not have any issue finding the Q1 ions 235 and 237 however when I run a product ion scan our instrument isn't picking up any product ions as shown in picture 1. I can find all the Q1 and Q3 ions in all other compounds (picture 2) except for 4,4'-DDT and I was wondering if anyone could offer some advice on how to proceed. I have included the transition table for DDT as provided by our standard supplier (picture 3) for […]
- by /u/just4fun420blazeitHello, We have Thermo Fisher Altis TSQ II MS. In my previous post I talked about inconsistent data post-preventative maintenance (PM). I have now realized that what I’m calling “data” post-PM are just artifacts with intensity scale 10^0 or 10^1 whereas the real analyte peaks are 10^6. I also just realized that the divert valve to my MS from LC is not connected. See the attached picture from Chromeleon showing valve “NC” which I believe means not connected. Moreover, in the command area, it also reads DivertValve A properties “DV_NOT_CONNECTED”. Subsequently, when I changed instrument method for my sequence to […]
- by /u/ThegreatgatoHi folks, I've been put in charge of ordering some new supplies for our 7900 and am looking for opinions on what cones to get. We've been using nickel-tip, copper base cones (either from Agilent or a third party) for a number of years. Would it be worth fighting for platinum tip cones? Our samples are digested in HNO3 and diluted to about 8% (with about 0.5 mL of HCl). The internal standard tee further dilutes them down to about 4%. They can be anything from meat to fruit juices, so the residual organic content varies. We analyze about 20 […]
- by /u/Fun-Conference814Who do you trust as your (UP- hopefully) LC (or GC) counterpart? I trust Waters for UPLC (and damn they just make the best C18 columns these days) but I am underwhelmed by Ultimate or Vanquish. My preferred MS is Orbitrap machines (Fusion, QE etc), but I feel the best would be a good marriage between the two. GC it's Agilent all the way, but I could be convinced if someone has a good experience. submitted by /u/Fun-Conference814 [link] [comments]
- by /u/just4fun420blazeitHello, In my lab we have Thermo Fisher Vanquish HPLC + TSQ Altis MS. We normally run a system suitability sample (SSS) before our real sample analysis and today, the SSS gave extremely inconsistent data even though the injections were from the same vial. Last week, we had LCMS preventative maintenance (PM) done where the field service engineer at the end did recalibrations with the CalMix and everything looked good. Before the PM, the data from the SSS injections was very consistent, with less than 5% coefficient of variation. Today, post-PM, everything is a mess. The peaks from the injections […]
- by /u/Melodic_Finance_2184Hello I have the capillary voltage stuck at 15kV. I tried to calibrate but the calibrations keeps failing. do you know why? submitted by /u/Melodic_Finance_2184 [link] [comments]
- by /u/PFAS123Hello guys, If you are in California (San Diego, Orange County or SF Bay Area) and looking for someone’s help to explore mass specs, set up a lab or want to troubleshoot the mass spec problem, please reach out to me and my team. I provide high level consulting work and also solutions to your need in the fraction of the price that you pay from Big Dawgs. From small molecules to Biopharma to Proteins, I have more than 8+ years of experience and my team members have experience more than 30+ years in mass spec. If there is a […]
- by /u/Slow-Put6296Hi everyone, I’m trying to understand real pain points in GC-MS/LC-MS data analysis workflows. For people who regularly process GC-MS or LC-MS data: What part of compound identification is still most manual or annoying for you? For example: choosing the right peak background subtraction extracting a clean spectrum NIST/library matching checking false positives integrating peak area batch processing many samples making final compound tables/reports explaining why a compound ID is reliable I’m especially interested in workflows where you look for specific compound groups, such as hydrocarbons, polymers/plastic markers, biomarkers, contaminants, metabolites, etc. What software do you use, and what still […]
- by /u/Junior-Exit-8841Dear MS Community, We recently inherited a Waters Xevo TQ-GC from a nearby company, and I just had the time to setup the instrument and put it on the bench. It's a 2021/2022 system with an Agilent 8890 and PAL RSI 85 autosampler. Unit looks brand new, and the GC counter has fewer than 100 injections total. We were told by this company they purchased the unit for an R&D project that never took off – given we're academic, we were very happy to inherit the instrument. I'm having a hard time figuring out how to tune the instrument as […]
- by /u/fcnd26submitted by /u/fcnd26 [link] [comments]
- by /u/bluemooninvestorsubmitted by /u/bluemooninvestor [link] [comments]
- by /u/Kathi_MSHey, could somebody help me with Skyline? It is about the peak are plot, whenever I work remotely on the instrument PC, Skyline somehow adds the sample name for every single sample in full length, what makes the bar chart then unreadable, since everything is really squeezed in. Does somebody know how to fix that in a better way than only importing the data into a functioning Skyline file? In the attached picture, blue is the problem and orange is how it should be. Thanks a lot! submitted by /u/Kathi_MS [link] [comments]
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