PURGE (Presaturation Utilizing Relaxation Gradients and Echoes) is a presaturation solvent suppression technique utilizing a z pulsed-field gradient. The technique is simple to set up and requires only the solvent frequency and presaturation power to be adjusted. It displays high selectivity, good phase properties, and flat baselines. It can be run with a minimum of 4 scans and combined with other multidimensional techniques such as TOCSY. Components may be filtered based on their T2 values. As with other presaturation techniques, exchangeable protons such as amides will show reduced intensity when suppressing water. For observing exchangeable protons, the excitation sculpting sequence is available.
Shown below are an unsuppressed proton spectrum and a PURGE spectrum of a 2mM sucrose sample dissolved in 90% H2O, 10% D2O at 400 MHz.