Sample must be prepared at ~ 0.1-1.0 mg/ml with a sample volume of ~0.05-0.1 ml using MeOH, ACN, or H2O. Avoid salts, DMSO and DMF, buffers, stabilizers and detergents.
Sample concentrations should be ~0.1-0.5 mg/ml. NEVER exceed a concentration of 1.0 mg/ml, if you do you can damage the GC column or the MS components.
Samples must be prepared in most volatile organic solvents, preferably acetone, methanol, hexane, aromatics, and alkanes. Less preferable are halogenated solvents (e.g. chloroform, methylene chloride, etc.) and ethers (e.g. diethylether, THF). DO NOT use water, DMF, or DMSO as a solvent. Place your sample in a GC-MS specified sample vial with the correct septum and cap, i.e. Agilent Part Number 5182-0714 (Pack of 100 screw top vials) and Agilent Part Number 5182-0717 (Pack of 100 Blue screw caps and PTFE/red rubber septas). Sample must fill at least half of the vial volume.
High Resolution MS Analysis
HR-ESI/APCI-MS analysis: Please provide at least 10 ug neat compound or prepare the sample at ~ 0.1-1.0 mg/ml with a volume of ~0.05-0.1 ml using MeOH, ACN, H2O, Acetone, or DCM. Avoid salts, DMSO and DMF, buffers, stabilizers and detergents.
Certain requirements need to be met in order to obtain good quality MALDI-TOFMS data:
1. Use only volatile solvents/buffers such as MeOH, H2O, CH3CN etc. Avoid using non-volatile agents such as salts (e.g. NaCl, CaCl2, KH2PO4), detergents (e.g. Triton, SDS), Urea, Guanidinium salts, and DMSO, DMF, and Glycerol.
2. If the above-mentioned components can’t be avoided, then purify. dialysis, ZipTips (Millipore Corporation), and reversed phase HPLC are good purification methods (use volatile solvents and buffers e.g. 50% ACN in water with 0.1% v/v trifluoracetic acid).
3. Sample with typical concentration of 5–100 µM and minimum volume of 2 uL is required. The total amount of sample needed for MALDI analysis is related to their molecular weight. For small molecular weight (1,000 or less) the minimum amount needed for analysis is 16 picomoles/microliter. The minimum for molecular weight 20,000 or less is 60 picomoles/microliter, and for 66,000 molecular weight the minimum amount needed for analysis is 160 picomoles/microliter.
4. Helpful information include: structure, sequence, molecular weight, type of compound, chemical reactivity, pH, sample amount/concentration, description of purification/isolation with focus on relative agents/solvents, suitable solvents, hazardous properties etc.