Abstract1,2,3‐Benzotriazin‐4‐one derivatives are extensively used as herbicides, insecticides and nematicides. Incorporation of these compounds into the human food chain is a cause for concern, since their toxicity to man is well documented.This work describes the development of a data‐base of classical 1,2,3‐benzotriazin‐4‐one fragmentation patterns and consequent sequential neutral mass losses which allows the prediction of the presence of a triazinone derived compound.Positive and negative ion tandem mass spectrometry techniques were employed since they allow rapid and sensitive structural characterization of drugs and their metabolites in biological fluids through the unambiguous monitoring of daughter ions from pre‐select