6  Suspect screening

6.1 Listing suspects

6.2 Suspect scoring

https://www.waters.com/waters/fr_FR/Mass-Accuracy-and-Resolution/nav.htm?locale=fr_FR&cid=10091028

Mass error (ppm):

\[\begin{equation} ME_{ppm} = \frac{mz_{theor} - mz_{meas}}{mz_{theor}} * 10^6 \end{equation}\]

where mz_theor is the theoretical exact mass (in u or Da) of the isotope, and mz_meas is the measured accurate mass from the instrument.

RMS of isotope mz error ppm:

\[\begin{equation} RMS_{mz} = \sqrt{\frac{\sum_{i=1}^n (ME_{ppm})^2}{n}} \end{equation}\]

At least mz of isotopes M+1, M+2 (n >= 2) should be included in the calculations to give good estimate of the average

RMS of isotope intensities (%):

\[\begin{equation} RMS_{Ab} = \sqrt{\frac{\sum_{i=1}^n (Ab_{theor} - Ab_{meas})^2}{n}} \end{equation}\]