Sample considerations

EI & CI

EI & CI Are gas phase processes, therefore the sample must be volatile and thermally stable. For OA EI, CI & GCMS:
- rmm < 500Da,
- MP < 150^oC
- Solvents: DCM, EA, cHexane; DO NOT USE AQUEOUS SOLVENTS.

ES, APCI & MALDI

ES, APCI & MALDI Are condensed phase techniques, therefore the samples must be soluble.
- For OA ES & APCI use MeCN, MeOH, H₂O or mixtures of these.
- Do not use DMF, DMSO or THF, check with MS staff if other solvents are used.
- Do not use involatile buffers.

Reporting Data

State method, ionisation mode:
e.g. LRMS (EI⁺): m/z 220, 80% (M⁺.); 205, 100% (M-CH₃)⁺
HRMS (ES⁺): Found 501.1234 Da (M+H)⁺, calculated 501.1238 Da

You should report the Base Peak (BP), Molecular Ion (MI) [or quasimolecular ion(s) (M+X)⁺] and any other significant peaks. For EI spectra the eight major peaks are considered representative. Remember higher mass ions of low intensity can be more important that high intensity low mass ions.