Xevo tq s mass spectrometry system

To quantify the RNA modifications, a multiple reaction monitoring (MRM) system was established based on LC-MS/MS (Acquity-UPLC I-class carrying a Xevo-TQ-S mass spectrometry system, Waters Corporation, Milford, MA, USA). Standardized ribonucleosides are used as LC-MS/MS standards in order to quantify the abundance of different RNA modification marks (Supplementary Fig. S1) in human sperm samples and these were prepared as previously described (Zhang et al., 2018 (link)). The original concentration of each ribonucleoside standard in the standard solution mixture is shown in Supplementary Table SII. In addition to the original full concentration, the mixture of standard solutions was diluted 2, 5, 25, 50, 200, 1000 and 2000 times, to obtain eight standard solutions of decreasing concentration (Supplementary Table SII). The standard curve for each RNA modification was obtained on the basis of concentration curve points that were corrected individually according to mass spectrometric signal.