a) CEST spectra of 20 mM EuDOTA(gly-OEt)4 3+ in water at pH 7, 9.4 T collected at temperatures of (■) 38ºC, (▲) 25ºC, (●) 15ºC, (□) 10ºC, and (○) 4ºC using a fixed B1 = 162 Hz and a presaturation time of 3 s. b) An Omega plot - Mz /(100 − Mz) vs 1/B12 – for 5 mM (▲), 10 mM (■) and 20 mM (●) Eu(DOTA-(glyOEt)4)3+ in water at pH 7 at 25°C using a 10 s saturation pulse at the indicated power levels.