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ESI-MS

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For polar small molecules, peptide, proteins: HPLC coupled to a UV detector and single quadrupole MS equipped with electrospray ionization; choice of small or large molecule chromatography, or direct sample injection.

 

Instrument: Waters 2795 HPLC system with dual wavelength UV detector, and ZQ single quadrupole MS with electrospray ionization source.

The ZQ open access LC-MS system handles a wide range of compounds, from small molecules to proteins; proteins of MW up to 95 kDa have been successfully analyzed by LC-MS using the C8 column. Usage fees are posted on the rates page.

Samples may be introduced to the mass spectrometer via loop injection or following HPLC on a reverse phase C18 or C8 column.

Loop injections are made using methanol (or alternatively, acetonitrile + 0.1% formic acid). The solution in the autosampler vial is injected directly the mass spectrometer.  Samples should be prepared in organic solvent (methanol, acetonitrile), and can contain up to 50% water if necessary.  Recommended injection volume: 25 uL

LC-MS analysis loads the sample onto an HPLC column for reversed phase chromatographic separation prior to UV and MS detection. The HPLC columns are 2.1 x 30 mm Agilent Zorbax columns with 3.5 um Stablebond stationary phases. Standard HPLC mobile phases consist of water and acetonitrile with 0.1% formic acid in each. Samples should be prepared in mainly aqueous solvent (90-98% water), and have neutral to acidic pH.  Recommended injection volume: 5 uL

The open access instruments are located in Bass 018, and are available 24/7 to trained users. Instrument-specific user accounts and card key access are provided following a mandatory hands-on training session. Training