MALDI/TOF-MS OF EIGHT SAMPLES AND ESI-MS ANALYSIS OF ONE SAMPLE

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The samples were analyzed by MALDI/TOF- MS and ESI-MS. The procedures are shown in detail below. Matrix-assisted laser-desorption time-of-flight mass spectrometry (MALDI-TOF) MALDI/TOF-MS was performed in the reflector positive ion mode using ¿-dihyroxybenzoic acid (DHBA, 20mg/mL solution in 50%methanol:water) as a matrix. All spectra were obtained by using a 4700 Proteomics analyzer (Applied Biosystems). ElectroSpray Ionization  Linear Ion Trap mass Spectrometry (ESI-LCQ/MSn) Mass analysis by LCQ-MS (Thermo Finnigan) was performed by direct infusion of permethylated glycans dissolved in 1 mM NaOH in 50% methanol ( 5 pmol/¿L) into the LCQ instrument at a constant flow rate of 1 ¿L/min via a syringe pump (Harvard Apparatus). The capillary temperature was set to 200oC and MS analysis was performed in positive ion mode. The collision energy was set at 35% for fragmentation in MS/MS.