Agilent 6530 q tof esi

Optical rotations were analyzed using a Rudolph Research Autopol III automatic polarimeter. UV and mass spectra were obtained using a Shimadzu 2020 EV LC–MS (Kinetex 1.7 μm C18 100 Å, LC Column 100 × 2.1 mm) using positive-and negative-mode electrospray ionization with a linear gradient of 5–95% acetonitrile MeCN–H₂O with 0.5% formic acid in 15 min followed by 95% MeCN for 3 min with a flow rate of 0.3 mL/min. Column chromatography was performed using a CombiFlash system using a HP CL18 reverse phase column. HPLC fractionation used a semi-preparative C₁₈ column of Kinetics New column. IR spectra were obtained using the PerkinElmer® Frontier FIR spectrometer, annotated by the PerkinElmer® Spectrum software suite. 1D and 2D NMR spectra were obtained on Bruker AV500 spectrometers at the UCLA Molecular Instrumentation Center. High resolution mass spectra were obtained from Agilent 6530 Q-TOF ESI with a 1260 Infinity LC with Autosampler at the UCLA Molecular Instrumentation Center.

The uncapped and capped RNA samples were desalted with ammonium acetate precipitation to replace the Na⁺ on the RNA backbone^{56 (link)}. The desalted RNA samples were dissolved in ultrapure water to 20 μM and analyzed with direct infusion method on a Q exactive plus orbitrap mass spectrometer (ThermoFisher Scientific) on negative mode with 70,000 resolving power at 200 m/z. 100 scans were acquired to improve the S/N.
SAM/SAH standard mixture and freshly purified MePCE_MT protein were analyzed on ZORBAX C3 column 3.0×150 mm with bead size 3.5 μm (Agilent Technologies) using Agilent 6530 Q-TOF ESI with a 1260 Infinity LC. Buffer A and B were 0.1% formic acid in water and 0.1% formic acid in acetonitrile, respectively. A linear gradient from 1–99% B was applied for a duration of 8 min and elutions were analyzed on positive mode of ESI-TOF mass spectrometer.