6510 a qtof mass spectrometer

LC-MS was performed using an Agilent 1100/1200 LC system connected to a 6510 A QTOF mass spectrometer (Agilent, UK). Samples of 10 µL TK at 0.2 µg/µL were injected onto an Agilent PLRP-S (150 mm × 2.1 mm, 1000 Å, 8 µm) column, maintained at 30 °C. Two mobile phases A (5% MeCN in aqueous 0.1% formic acid) and B (95% MeCN, 5% water, 0.1% formic acid) were used at 0.3 mL/min. The column was pre- equilibrated at 25% B for 1.9 min, before injection, held for 1 min further at 25% B, and then a gradient elution increased B to 99% over 16 min. After 2 min, B was decreased to 25% over 0.1 min. The QTOF mass spectrometer scanned m/z from 100 to 3100 Da. Positive electrospray ionisation (ESI) was used with 4000 V capillary voltage, fragmentor at 175 V, skimmer at 65 V and octopole RF peak at 750 V. Nitrogen was used as the nebuliser and desolvation gas at a flow of 5 L/min. Spectra were acquired every second with an acquisition time of 1000 msec/spectrum. Lockspray was used during analysis to maintain mass accuracy. Data were processed in MassHunter software (version B.07.00) and deconvolved using the maximum entropy deconvolution algorithm.

LC-MS was performed using an Agilent 1100/1200 LC system connected to a 6510 A QTOF mass spectrometer (Agilent, UK), as described previously⁶ . Triplicate fermentations were performed for each sample.