“…Electrospray Ionization Mass Spectrometry (ESI-MS) was successfully employed for detection a G-quadruplex structure formation in 1993 (Goodlett et al, 1993). Since then the technique has been a useful tool in structural studies of G-quadruplexes, including strand stoichiometry (Joly et al, 2012;Borbone et al, 2011;Cui and Yuan, 2011;Rosu et al, 2002 andZhou et al, 2007), quadruplex-ligand interactions Li et al, 2008;Gabelica et al, 2007), structural transitions Amato et al, 2009 andLi et al, 2009), the kinetics of structure formation (Rosu et al, 2010;Gabelica et al, 2009) and many others (for a review, see Yuan et al, 2011).…”