BP4NTA » All Posts https://nontargetedanalysis.org/forums/feed/ Thu, 04 Jun 2026 09:17:17 +0000 https://bbpress.org/?v=2.6.14 en-US https://nontargetedanalysis.org/forums/topic/leaky-viper-lines/#post-3556 <![CDATA[Reply To: Leaky Viper Lines]]> https://nontargetedanalysis.org/forums/topic/leaky-viper-lines/#post-3556 Mon, 31 Mar 2025 15:52:33 +0000 bp4nta We used to have issues with viper and nanoviper lines but now we use a torque screwdriver (H4DETSD) with a hexagonal adaptor bit with a cutout for the line to tighten the lines to ~30 cNm and ~20 cNm for metal viper and glass nanoviper connections respectively. We also do a near fully connected leak check with a pre-detector plug (closed system). This has resolved all viper tightening leak issues for us.

]]> https://nontargetedanalysis.org/forums/topic/exporting-as-mzvault-library-from-coumpound-discoverer/#post-3523 <![CDATA[Exporting As MzVault Library from Coumpound Discoverer]]> https://nontargetedanalysis.org/forums/topic/exporting-as-mzvault-library-from-coumpound-discoverer/#post-3523 Wed, 12 Mar 2025 11:54:38 +0000 bp4nta Hi,
I usually export my spectras as MzVault libraries from the Coumpound Discoverer. Strangely, from one of mine result file the software does not give me the possibility to export the data as MzVault library. Any suggestions?
P.S. I In my workflow, I obviously included the Mz Vault.
Please Help me!

]]> https://nontargetedanalysis.org/forums/topic/leaky-viper-lines/#post-3399 <![CDATA[Leaky Viper Lines]]> https://nontargetedanalysis.org/forums/topic/leaky-viper-lines/#post-3399 Tue, 14 Jan 2025 19:41:36 +0000 gpblack Has anyone had issues with leaky Viper lines on a Thermo LC? It seems anytime I have to mess with one, it takes me a few tries to get it attached to where it won’t leak. Is this common or do I have worn out fittings (or some kind of user error)?

]]> https://nontargetedanalysis.org/forums/topic/quantifying-fsddms2-data-in-tracefinder/#post-2974 <![CDATA[Quantifying FSddMS2 Data in TraceFinder]]> https://nontargetedanalysis.org/forums/topic/quantifying-fsddms2-data-in-tracefinder/#post-2974 Mon, 06 May 2024 18:45:33 +0000 gpblack [HRMS but not NTA-related] Is anyone quantifying FSddMS2 data in TraceFinder? Is there a way to make it read your MS2 data for qualifying ions? It seems to only be using my MS1 scan for my quantifier AND qualifiers.

]]> https://nontargetedanalysis.org/forums/topic/temporal-sampling-paired-or-unpaired/#post-2931 <![CDATA[Reply To: Temporal sampling- paired or unpaired?]]> https://nontargetedanalysis.org/forums/topic/temporal-sampling-paired-or-unpaired/#post-2931 Tue, 19 Mar 2024 23:39:19 +0000 bp4nta Also not a statistician, but I think this is unpaired t-test for sure. Like you say, you have different numbers of samples in each time point. I guess you want to see if there is a systematic difference (increase or decrease) from season to season, which would be a good case for paired. If it was paired, it would have to be on the means, since the individual replicates can’t really be linked to each other I don’t think. Do you have to do ANOVA also?

]]> https://nontargetedanalysis.org/forums/topic/dealing-with-near-outlier-in-3-group-nta-set/#post-2929 <![CDATA[Dealing with Near “outlier” in 3 group NTA Set]]> https://nontargetedanalysis.org/forums/topic/dealing-with-near-outlier-in-3-group-nta-set/#post-2929 Tue, 19 Mar 2024 23:34:02 +0000 bp4nta I have a set of data from solid phase microextraction GC-MS (single quad) analysis of the headspace of three types of cheese samples. I used MS DIAL to do alignment and identification using the NIST library and RI matching. I used a set of method blanks to test for significance in the features (testing vs. the maximum of the 99% confidence interval), and ended up with 139 features. The cheese types are a ‘control’ cheese, and then the control cheese soaked in two types of wine- ‘alicante’ wine and a ‘cabernet’ wine. A primary question is the differences in the volatile profile between the cabernet and alicante soaked wine.

I did a volcano plot from the abundances (4 sample replicates for each cheese) and it looks like there are a lot of high-fold change relationships that are not statistically significant (unpaired t-test, p =0.05). I think this is because of high variability in the cabernet cheese samples. This is backed up, I think, by the PCA (z-score normalized), which shows not much grouping between the cabernet replicates as compared with the alicante and control. Both are attached.

I am curious if anyone has ideas about different tests that might be able to tease out differences that look like they are there but are not statistically significant by the test I did. Or maybe a better way to preprocess the abundance data prior to testing or PCA?

Attachments:
You must be logged in to view attached files.
]]> https://nontargetedanalysis.org/forums/topic/commercial-labs-offering-nta/#post-2888 <![CDATA[Reply To: Commercial Labs Offering NTA]]> https://nontargetedanalysis.org/forums/topic/commercial-labs-offering-nta/#post-2888 Thu, 22 Feb 2024 13:49:03 +0000 bp4nta The state of California is working with one, but I’m not working on that project. Perhaps @mccord can share?

]]> https://nontargetedanalysis.org/forums/topic/fragmentation-spectra-for-different-adducts/#post-2887 <![CDATA[Reply To: Fragmentation spectra for different adducts]]> https://nontargetedanalysis.org/forums/topic/fragmentation-spectra-for-different-adducts/#post-2887 Thu, 22 Feb 2024 13:41:26 +0000 bp4nta Have you considered running these through any in silico fragmenters? Even the “MassSpec Scissors” in ChemSketch could be enlightening.

]]> https://nontargetedanalysis.org/forums/topic/starting-nta-methods-for-waters-synapt-xs-qtof/#post-2886 <![CDATA[Reply To: Starting NTA methods for Waters Synapt-XS QTOF]]> https://nontargetedanalysis.org/forums/topic/starting-nta-methods-for-waters-synapt-xs-qtof/#post-2886 Thu, 22 Feb 2024 13:37:30 +0000 bp4nta I’d personally reach out to Angela Batt since she has a Waters QTOF. This just got published, but if I remember correctly points to other papers for some of the methods parameters. https://doi.org/10.1021/acs.est.3c07514

]]> https://nontargetedanalysis.org/forums/topic/finding-features-unique-to-groups/#post-2885 <![CDATA[Reply To: Finding Features Unique to Groups]]> https://nontargetedanalysis.org/forums/topic/finding-features-unique-to-groups/#post-2885 Thu, 22 Feb 2024 13:34:31 +0000 bp4nta *Disclaimer, not a statistician*
Volcano plots? This plots the fold change versus p-value (significance). Anything outside some set criteria in both axes would be the ones to look at.

https://en.wikipedia.org/wiki/Volcano_plot_(statistics)

]]>