Esi ltq mass spectrometer

LC-MS analysis was performed using a Paradigm MG4 micropump system (Michrom Biosciences, Auburn, CA) and ESI-LTQ mass spectrometer (Thermo Fisher Scientific, San Jose, CA). Separation of derivatized glycans was performed on hydrophilic interaction chromatography (HILIC). A HALO Penta-HILIC column (2.1 mm × 150 mm, 5 μm particle size) was used. Mobile phases A and B were 10 mM ammonium formate in water (pH 6.5) and 98% ACN contained 0.1% formic acid, respectively. 10 μL of sample was injected at the initial gradient condition (80% mobile phase). The gradient was then ramped from 80% to 50% solvent B over 25 min with a total run time of 40 min. Glycans were eluted at 0.2 mL/min. The positive ion mode was used for analysis. The MS detection range was set at 800 to 2000 m/z. The ESI spray voltage and capillary voltage were set at 5 kV and 35 V, respectively, with the stainless steel capillary heating to 275 °C.

Nano LC–MS/MS conditions were as described in previous work [17 (link)]. A Magic C18 capillary column (100 μm × 15 cm; 3 μm particles, 200 A) (Michrom Biosciences, Auburn, ° CA) was used for LC separation, and gradient elution was performed using a Paradigm MG4 micropump system (Michrom Biosciences) with a flow rate of 350 nL/min. The mobile phase A was 2% ACN with 0.1% formic acid in water and mobile phase B was 2% water with 0.1% formic acid in ACN. The analytical gradient lasted for 80 min where the composition of solvent B increased from 5 to 32% in 50 min, followed by a washing and equilibration step where solvent B increased to 95% in 1 min and was held for 4 min, and then returned to 5% B in 0.1 min and was held for 25 min.
An ESI-LTQ mass spectrometer (Thermo Fisher Scientific, San Jose, CA) operated in positive-ion mode was used for analysis. The ESI spray voltage and capillary voltage were set at 2.2 kV and 45 V, respectively. Collision ionization dissociation (CID) fragmentation was performed at 35% of the normalized collision energy. The mass spectra were acquired in a data-dependent manner. Following a full scan in the mass range of m/z 400 to 1800, CID MS/MS was performed on the five most intense ions.