Distorted Peaks in Scheduled MRM
I am seeing very strange behavior in sMRM. In the attached file, you will see XIC for different scan times ranging from 0.2s to 1s. I think I undertand the scan time correctly: if the peak width is 15 seconds and the scan time is 1s, I will get about 15 scans per peak. So cutting the scan time to 0.5s, I should be getting 30 scans per peak. I am hoping it is something simple in my method or hardware, and somebody will be able to help me with this. I will supply the files if needed. Please look at the attached file to see the chromatograms. I don't think it is a chromatography issue - I will run the same analytes without sMRM for comparison.
City of Scottsdale Water Quality Lab
I should mention I am running Analyst 1.6.3 on QTRAP4000.
Hi Ivo, I'll reach out to our support team to take a look at this. Stay tuned.
From our Support Team: Following up on this question and in reviewing the most recent MRM & sMRM data sets. There were many more points across the MRM & sMRM peaks when using 75ms dwell time. You can see the increase in number of data points across the peaks through PeakView. In both data sets, you can see the effect of different Gaussian Smooth values vs. peak appearance. Peak area seemed to be ~10% better with sMRM data, but overall MRM peak areas were very comparable.
Suggestion to use a value of 3 for smoothing in his MQ processing method.