Open crestre opened 11 months ago
I have no experience with Waters software - but the file you exported can indeed not be read/imported with mzR
(the package we are using to import the data). Seems that a variable "instrument_name" is missing. Would it be possible to configure the Waters software to also export that variable?
Or, leave netCDF behind and go straight to export/conversion to mzML ? Can Proteowizard https://proteowizard.sourceforge.io/ convert your data ?
Also, try to avoid the ancient xcms classes xcmsRaw and xcmsSet. They are not maintained anymore, in favour of the new xcms3 interface described in the vignette http://bioconductor.org/packages/release/bioc/vignettes/xcms/inst/doc/xcms.html
Yours, Steffen
Johaness and Steffen,
A little bit late but thanks for your response. I tried Proteowizard but it is not "seeing" the files. I am running R version 4.3.1 and cannot make mzR to work on the data from msdata. Any suggestion? Finally, as a new user of metabolomic data and potentially xcms, I found myself going through multiple vignettes/versions - in the end I figured out what was going on ... Thanks
Could you give more information about that instrument and data ? In the netCDF I see
"QDa Positive(+) Scan (100.00-600.00)Da, Centroid, CV=15"
and "No Chromatography" ; "Direct Inlet Probe" ; "Electron Impact" ; "Positive Polarity"
.
Which is not exactly matching "Waters HP-LC".
Yours, Steffen
But, partly successful. I don't think it is the missing instrument that breaks xcms:
library(xcms)
ms <- openMSfile("Export_2023_07_241045.cdf")
summary(header(ms))
...
retentionTime lowMZ highMZ
Min. :180.1 Min. :-1 Min. :-1
1st Qu.:285.0 1st Qu.:-1 1st Qu.:-1
Median :390.0 Median :-1 Median :-1
Mean :390.0 Mean :-1 Mean :-1
3rd Qu.:495.0 3rd Qu.:-1 3rd Qu.:-1
Max. :600.0 Max. :-1 Max. :-1
which looks weird. There are some scans:
> length(peaks(ms))
[1] 2801
> peaks(ms)[c(1, 666, 2801)]
[[1]]
mz intensity
[1,] 241.4680 5891.645
[2,] 263.2248 2627.645
...
[9,] 399.2110 9669.469
[10,] 411.7138 7557.469
[[2]]
mz intensity
[1,] 114.1244 2307.645
[2,] 120.7768 5507.645
...
[24,] 469.4253 8069.469
[25,] 556.5388 9477.469
[[3]]
mz intensity
[1,] NA NA
[2,] 582.9421 7813.469
and the last one looks broken, the NA is likely to throw off calculations like min/max. Rather than "fixing" xcms to silently throw that away, I like the error (though the error message is not helpful ...) to indicate the data is broken. I don't know how to edit/fix netCDF files, though.
Yours, Steffen
One more thing:
if you ignore my comment about not using xcmsRaw
, the following works:
xr <- xcmsRaw("Export_2023_07_241045.cdf", scanrange=c(1:2800))
The latter shows this data:
but you'd need to play with parameters to find peaks:
xs <- xcmsSet("Export_2023_07_241045.cdf", scanrange=c(1:2800))
Warning message:
In xcmsSet("Export_2023_07_241045.cdf", scanrange = c(1:2800)) :
No peaks found in sample Export_2023_07_241045.
Yours, Steffen
I am learning about hp-lc data using xcms and obtained an error message when I was trying to import a .cdf file using xcmsRaw. The file was generated in a Waters HP-LC. I am wondering whether I am exporting the data incorrectly or if there something else that I have to be aware of. I am attaching the file just in case.
Many thanks for any help that you can provide.
Carla Export_2023_07_241045.cdf.zip