European Journal of Mass Spectrometry - Abstract of Analysis of global DNA methylation levels in human blood using high- performance liquid chromatography/tandem electrospray ionization mass spectrometry

Huimin Ma,^a,b Wenbing Zhang,^a,* Junjie Hu,^a,b Zhiqiang Yu,^a Yong Chen,^a,b Qiong Luo,^c Xiaoliu Shi,^d Yingying Zhang,^e Renfang Song,^a Zhen Zhou,^a Guoying Sheng^a and Jiamo Fu^a
^aState Key Laboratory of Organic Geochemistry, Guangzhou Research Center of Mass Spectrometry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. E-mail: zhwb@gig.ac.cn
^bGraduate School of the Chinese Academy of Science, Beijing, China
^cLicheng Hospital, Zengcheng District, 511300, Zengcheng, China
^dThe Second Xiangya Hospital of Central South University, No.139, Renmin Road, Changsha, Hunan, China
^eSchool of Engineering and Science, Jacobs University, Campus Ring 1, 28759, Bremen, Germany

DNA methylation plays an important role in both normal physiological and disease processes. In this study, a sensitive and precise liquid chromatography-electrospray ionization tandem mass spectrometry method has been optimized for quantification of global DNA methylation levels in human peripheral blood by using multiple reaction monitoring (MRM) mode. This method was then used to analyze age-dependent association of DNA methylation. The results showed that the limit of detection was 1 pg for 5-methyl-2′-dexycytidine (5mdC) (S/N = 5.6). The linear calibration curves with correlation coefficients higher than 0.9990 were ranged 0.75–10 ppm and 0.0375–0.5 ppm for 2′-dexycytidine (dC) and 5mdC, respectively. The relative standard derivatives (RSD) of inter-day, intra-day and parallel samples were less than 5%. The analysis results of the blood samples from 60 healthy individuals showed that the child group had the highest mean 5mdC content while the adult group had the lowest values.