Exact mass and m/z calculator ESI pos ESI neg ESI pos Molecular formula C H O N P S – Exact mass z=1 z=2 z=3 z=4 z=5 z=6 z=7 z=8 z=9 ESI neg Molecular formula C H O N P S – Exact mass z=1 z=2 z=3 z=4 z=5 z=6 z=7 z=8 z=9 Weight data (atomic and exact) were obtained from the Commission on Isotopic Abundances and Atomic Weights (https://www.ciaaw.org/atomic-weights.htm) Envelope Copyright 2021 potard.ch