The following guideline should be followed when you prepare your samples for mass spectrometry.
Should you have any questions on what may or may not be used, please contact the TML manager.
Rules for LC/MS solvents and modifiers:
Safe solvents (volatile, low molecular weight protic):
Safe mobile phase modifiers:
- Acetic acid (up to 1.0%)
- Formic acid (up to 0.1%)
- Ammonium hydroxide (up to 0.1%)
- Ammonium formate (salt concentration = 10 mM or less)
- Ammonium acetate (salt concentration = 10 mM or less)
DO NOT USE:
- Nonvolatile salts (Tris, phosphates, citrates and HEPES) can deposit in source and plug capillaries.
- Surfactants/Detergents such as SDS, CHAPS, PEG, Tween, and Triton that suppress electrospray ionization.
- Inorganic acids (Sulfuric, nitric and hydrochloric acids) which are corrosive and destructive for the LC/MS/MS system.
- DMSO, DMF, THF, acetate and glycerol.
- Trifluoroacetic acid (TFA) suppresses positive-ion electrospray at level exceeding 0.01%. Commonly used alternatives to high concentrations of TFA are mixtures of either 1% acetic or 0.1% formic acid with 0.025% TFA.
- Hydrocarbon solvents (hexane and benzene) cannot be used for ESI.Triethylamine (TEA) that yields an intense an intense [M+H]+ ion at m/z 102 and suppresses positive-ion electrospray of less basic compounds.
Concentration and Volume:
- For ESI and APCI analysis, please submit 100 µL of (at least) 10pmol/µL sample solution or 1000 pmol of dried material.
- The samples should be submitted in polypropylene vials or deactivated glass vials with PTFE or polypropylene-lined screw caps. Use a small volume insert (300 or 500 µL) if a limited amount of sample is available.
- All sample tubes/vials MUST BE labeled with a sample ID and MUST BE accompanied by a Sample Submission Form (PDF).