We are detecting methyl methacrylate monomer using air sampling. The signal is so low, we will need to use gain factors. Can I apply gain to a certain region of the TIC or does it have to be applied to the whole chromatogram? My signal height of MMA is currently at 4E+4, other compounds in the standard are at 6E+6 height, what is the suitable gain factor for us?
paulsalverda thank you for such detailed explanation. I am attaching overalys of our scan and sim with the background:
After subtraction of the MS spectrum, the peak is identified as methyl methacrylate.
We have no idea what the other peaks in our SCAN are as you can see they are not in the background and their eights vary with replicate injections. We hypothesise that these are random reactions of MMA (we have a manuscript that might support this, but more investigation is needed). The screen shout of our calibration standards are here:
Standards go from 5ug on tube to 2.5, 1.25, 0.625.
Building calibration curve with SIM
Leads to a slope of 0.3 and R2 of 0.99.
Other peaks in the TIC SCAN do not show any trend during calibration.
We have just initiated a times segment increase in gain. Hopefully, this will solve issue.
We have also tested exhaustive desorption of MMA from tube by checking consecutive desorptions from a spiked tube and we see no left over MMA in the second desorption. We also checked for breakthrough from our tube during spiking and we see no evidence of that.
paulsalverda thank you for such detailed explanation. I am attaching overalys of our scan and sim with the background:
After subtraction of the MS spectrum, the peak is identified as methyl methacrylate.
We have no idea what the other peaks in our SCAN are as you can see they are not in the background and their eights vary with replicate injections. We hypothesise that these are random reactions of MMA (we have a manuscript that might support this, but more investigation is needed). The screen shout of our calibration standards are here:
Standards go from 5ug on tube to 2.5, 1.25, 0.625.
Building calibration curve with SIM
Leads to a slope of 0.3 and R2 of 0.99.
Other peaks in the TIC SCAN do not show any trend during calibration.
We have just initiated a times segment increase in gain. Hopefully, this will solve issue.
We have also tested exhaustive desorption of MMA from tube by checking consecutive desorptions from a spiked tube and we see no left over MMA in the second desorption. We also checked for breakthrough from our tube during spiking and we see no evidence of that.
