Uhplc vanquish pump

Samples analysis was performed using a system comprised of a UHPLC Vanquish pump, Vanquish Autosampler, Vanquish UHPLC + column compartment, and ISQ EC mass spectrometer (ThermoFisherSci.), in conjunction with ThermoFisherScientificDionexChromeleon 7 Chromatography Data System software. A C18 column (4.6 mm ID X 100 mm L, 5 µm, 120 Å; Acclaim 120; ThermoFisherSci.) was used with a 0.25 mL/min. flow rate and 0.5 µL injection volume; the autosampler needle was washed with 10% (v/v) methanol (10 s) after each sample injection. Mobile phases A and B consisted of 10 mM ammonium acetate and LC-MS grade acetonitrile, respectively. The linear gradient mobile phase flow was characterized by an increase in acetonitrile from 50% to 80% between 0 to 4 min, followed by a decrease to 50% between 4 to 8 or 15 min. Preliminary results guided selection of the following mass spectrometric parameters: vaporizer temperature (VT) = 250 °C; ion transfer tube temperature (ITT) = 200 °C; optimum sheath gas pressure (SGP) = 25 psig; auxiliary gas pressure (AGP) = 2 psig; sweep gas pressure (SWGP) = 0.5 psig; and negative mode, which resulted in an extracted Gln-FMOC chromatogram at m/z 367.1. Column and autosampler temperatures were maintained at 35 °C and 15 °C, respectively. This method represented here as Gen-MS-I.