Through equation 2, the TP and TN probability for a CNL can be obtained, which were used to calculate the score CN L (Equation ). This score is used to evaluate whether a CNL belongs to a specific precursor ion mass. To calculate this score CN L , the TP and TN sum of probability (i.e., P (T P |CN L) and P (T N |CN L), respectively) are obtained for a specified CNL ± mass tolerance. For example, if the mass tolerance is set to 0.010 Da and a CNL mass of 18 has been found, then the P (T P ) corresponds to the summed TP probabilities of the CNL masses 17.99 till 18.01. After similarly calculating the P (T N ), the score CN L can be used to assess if the CNL in question relates to a true fragment mass of the precursor ion mass or not, corresponding to above or below the score CN L threshold,