The structural properties of G-quadruplex forming sequences, such as the human telomeric repeat d(T2AG3)n, are of great interest due to their role in cancer and cellular aging. To determine if G-quadruplexes are present in a solvent-free environment, different lengths of the telomeric repeat d(T2AG3)n (where n = 1, 2, 4 and 6) and dTG4T were investigated with mass spectrometry, ion mobility and molecular dynamics calculations. Nano-ESI-MS illustrated quadruplex stoichiometries compatible with G-quadruplex structures for each sequence, with dT2AG3 and dTG4T forming 4-strand complexes with two and three NH4+ adducts, d(T2AG3)2 a 2-strand complex, and d(T2AG3)4 and d(T2AG3)6 remaining single-stranded. Experimental cross sections were obtained for all species using ion mobility methods. In all cases, these could be quantitatively matched to model cross sections with specific strand orientations (parallel/antiparallel) and structures. For each species, the solvent-free structures agreed with the solution CD measurements, but the ion mobility/modeling procedure often gave much more detailed structural information.