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Protocols of MSn Spectra Acquisition

 

These instructions are based on the condition that uses of a MALDI-QIT-TOF mass spectrometer . Please follow the CID spectra acquisition protocol below when you compare your spectra with the spectral image in GMDB.

 

Instrument: MALDI-QIT-TOF MS

 

CID spectra acquisition:

1.     Place 0.5 μL of a sample solution on a target plate and allow it to dry.  Cover the dried analyte on the target plate with 0.5 μL of the matrix solution (10 mg/mL of 2,5-dihydroxybenzoic acid in 30% ethanol) and allow it to dry. Then, recrystallize the dried material by adding 0.15 μL of 99.5% ethanol to the matrix-analyte mixture on the target plate. 

2.     Acquire MS spectra of glycans in the positive mode.

3.     Acquire MS2 spectra of sodium adduct ions derived from the glycans. For the acquisition of CID spectra, adjust the CID energy so that the signal of precursor ion almost disappears. If the intensity of precursor ion in the spectrum is more than 15% of the base peak, the spectrum must be discarded and reacquired with a larger CID energy. Use an automatic acquisition function with the regular raster that governs the laser shot patterns.

4.     Acquire MS3 spectra of all the major fragment ions in the MS2 spectra in the same manner as described above for MS2 acquisition.