Previously, the proton affinity (PA) of an analyte was used to predict whether the protonated analyte would undergo diagnostic product formation or proton transfer or if there is no reaction. These proton affinity values were then compared to that of MOP to hypothesize whether a diagnostic product ion would be formed over no reaction or proton transfer from the protonated analyte to MOP. If the PA of the analyte is lower than that of MOP, proton transfer usually dominates. On the other hand, if the PA of the analyte is greater than that of MOP, a diagnostic adduct may be formed. However, accurate predictions between formation of the diagnostic adduct and no reactions were not possible. Nevertheless, PA values may be used as a baseline for benchmarking potential machine learning methods or as a source for additional input features.