Before we start, a question: What do you think is the most important part of any MS experiment/analysis/project?
Answer: Sample Preparation!!!! and then the right combination of sample introduction, ionization method, mass spectrometer and mode of operation. To help us decide, please read the following carefully:
- Please complete the Sample Submission Form in full as this provides information necessary to allow us to assess the best methodology to apply.
- Please consult the Facility Manager before starting any MS project.
- At a minimum, HPLC grade solvents and Milli-Q water should be used for sample preparation.
Some General Sample Submission Guidelines:
- Please complete the sample submission form in full
- Samples containing radioactive, magnetic substances or living organisms will not be accepted for analysis.
- Samples will be returned to you with the results.
-
Do
you
have
a
method
(from
the
literature)
for
the
analysis
you’re
proposing?
- Choice of column and temperature program (GC/MS) or column, mobile phase, injection solvent and gradient profile (LC/MS)
- Sample should be submitted as solids in Eppendorf tubes (preferred) or in a volatile solvent (GC or HPLC glass vials) free of detergent, involatile salts/buffers, etc.
- For infusion, ESI samples will be run in 1:1 MeOH/H2O+0.1% formic acid (+ve ion) or 1:1 MeOH/H2O+0.2%NH4OH (-ve ion) unless otherwise specified.
- Suitable buffers for ESI and MALDI: ammonium acetate, ammonium formate or ammonium bicarbonate
- Suitable organic solvent for proteins: acetonitrile, methanol, and/or water
- Suitable organic solvent for small organics: methanol, ethanol, acetonitrile, dichloromethane, chloroform, ethyl acetate, diethyl ether etc
- MALDI is more forgiving from a solvent perspective but the choice of matrix and how the sample is applied to the target is critical to achieving a good result. This NIST website is a great resource for synthetic polymer samples however the scientific literature may be a better choice.
Some things to bear in mind:
- Samples containing involatile salts/ buffers or contaminants introduced during the sample preparation/synthesis should be avoided if at all possible or removed before sample submission. Please see "Ion Suppression and ESI".
- For ESI/APCI/EI only samples in solution can be introduced to the mass spectrometer
- Choice of ionization method and instrument is critical to a successful result, if you’re not sure ask the Facility personnel and we will be happy to help!