Quasar danielacgranato  2018-10-17


I have just starting working with Quasar and I am getting an error message from the software. I have attached the document I started working with. I only have standard samples, that I ran in triplicate and I would like to calculate LOD and LOQ.

Can you help me with this?

Thank you very much in advance.
Best, Daniela

Nick Shulman responded:  2018-10-17
What is the text of the error message are you seeing?

Also, you should send us a .sky.zip instead of just the .sky file.

In Skyline, you can use the menu item:
File > Share > (complete)
to create a .zip file containing your Skyline document and supporting files including spectral libraries and extracted chromatograms.

If that .zip file is less than 50MB, you can attach it to this support request. Otherwise, you can upload it here:

By the way, Skyline-Daily has some new features related to LOD and LOQ if you don't want to use Quasar. In Skyline-Daily, these features are available at:
Settings > Peptide Settings > Quantification
-- Nick
danielacgranato responded:  2018-10-19

I have attached the skyline zipped document. The error I am receiving is that sample ID, anayte concentration and IS spike are missing in the document and that I should re-install Quasar. Is that a common error?

I would like to calculate LOD and the concentration of the analyte on samples that I do not know the concentration of the analyte, do you recommend I should use Quasar?Do you have a tutorial?

Thank you very much.

Best, Daniela
Nick Shulman responded:  2018-10-19

You have not attached any files. Can you try again?

I do not know anything about what Quasar does.

You can certainly use the calibration curve features in Skyline to fit a calibration curve to your external standards and calculate concentrations of unknown samples.
Here are the absolute quantification tutorials and webinars in Skyline:
-- Nick
danielacgranato responded:  2018-10-20

Thank you very much for the response. I have attached the error I am getting from Skyline when I launch Quasar in Tools>Quasar.

I read the tutorial for absolute quant and I have fitted the values on a calibration curve with my external standards (I have attached the Skyline document and the print screens in the ppt document). I understand now that the next step is to run an unknown sample and be able to get the absolute quantification of my analyte by fitting it in to the curve. Still, I would like to know if Skyline can give me the value for LOD for each peptide and other parameters that are important for absolute quant like precision, CV etc? Or for that do you recommend I should use Quasar?

Thank you very much. Best, Daniela.
danielacgranato responded:  2018-10-20
I am re-sending the attached documents.

Thank you. Best, daniela