Prepared Sample Analysis (ESI or GC/MS)

ESI - Prepared sample analysis is a service with a discounted rate (currently $30 per sample)* that is applicable to samples that are prepared a specific way and that can be analyzed using electrospray ionization. This service is ideal for those who need high resolution (30,000 or better) or exact mass measurements (5 parts per million or better – up to m/z 2,500)) and is applicable to a wide variety of different samples, ranging from small molecules to peptides and proteins.

Prepared samples will be introduced into the mass spectrometer as they are received using an autosampler. Prepared samples can only be analyzed by electrospray ionization. As opposed to our regular service samples, prepared sample will only be analyzed once with pre-set tune parameters. The facility staff will not try additional tuning parameters or other ionization techniques.

If the prepared sample analysis fails to produce an acceptable mass spectrum, we will be happy to work with you to investigate whether changes to the sample preparation or a different ionization technique will produce better mass spectral data.

The requirements for ESI - prepared sample are:

• The sample must be completely dissolved. No salts or buffers may be present.
• Allowed solvents: Methanol, acetonitrile, water.  Up to 10% acetone, dichloromethane, chloroform, DMF or DMSO.
• Sample concentration: Up to 50 micromolar.
• Sample must be filtered through a 0.45 micron filter prior to submission.

GC/MS – Prepared sample analysis.  If your sample can be analyzed by GC/MS, you can also submit it for Prepared Sample Analysis.
Prepare your sample according to these guidelines:

• The sample must be volatile and dissolved in a non-polar solvent (e.g. acetone, hexane or dichloromethane). 
• The expected molecular weight should be below 400 Da.
• Sample concentration: Up to 100 ng/µL
• Sample must be filtered through a 0.45 micron filter prior to submission.

If your sample meets these criteria, you can get an electron impact mass spectrum (1000 resolution, exact mass measurement is extra) for $30.

For questions regarding prepared sample analysis, please contact Dr. Ulla Andersen (email: norklit AT berkeley DOT edu)

* Please note: College of Chemistry users automatically receive a 66% discount on all fees (except the open access yearly fee and the consultation fee) when a Chemistry account number is used courtesy of the CCHEM Dean’s Office.