Lastly, for the classification of the potential mono-iso pair, the TP and TN probabilities are obtained using equation 6. These probabilities were converted to probability percentages (i.e., on a scale of 0 to 100). Due to the wide range of values that can be obtained for the TP and TN probabilities, a score EM D is used instead for the evaluation (Equation ). Here P(TP) and P(TN) equal the true positive and true negative probabilities, respectively. This score EM D ranges between 1 and minus infinity. In case the potential mono-iso pair has a score EM D above a set threshold, the potential isotopologue is classified as a correct isotopologue of the monoisotopic ion. An example for the calculation of the score EM D can be found in figure score EM D = 1 -P (T N ) P (T P )