Synapt g2 si esi ms mass spectrometer

Final steps of small-molecule purification was conducted by high-performance liquid chromatography using a Varian ProStar with VYDAC reverse-phase columns (4.6 × 100 mm, 1 ml min⁻¹, analytical; 10 × 100 mm, 3 ml min⁻¹, semi-preparation; Supplementary Fig. 12–58; Supplementary Methods). The mobile phase was composed of A: 5% ACN; 95% H₂O; and 0.1% TFA(v/v), and B: 95% ACN; 5% H₂O; and 0.08% TFA (v/v). The solution NMR spectra of small molecules were recorded on 400, 500 and 600 MHz Agilent spectrometers. The deuterated solvents used for O-tert-butyl ester protected and deprotected (O–COOH) oligoquinolines were CDCl₃ and (CD₃)₂SO, respectively. Splitting patterns that were difficult to interpret are indicated as multiplet (m) or broad (b). Mass spectra were obtained using either MALDI-TOF Voyager DE Pro (Yale University, CBIC centre) or University of Illinois Mass Spectrometry Facility. High-resolution electrospray ionization mass spectra were obtained using the Waters Synapt G2-Si ESI MS mass spectrometer (Milford, MA, USA).