NMR with multiple receivers.

Parallel acquisition NMR spectroscopy (PANSY) is used to detect simultaneously signals from up to four nuclear species, such as H-1, H-2, C-13, N-15, F-19 and P-31. The conventional COSY, TOCSY, HSQC, HMQC and HMBC pulse sequences have been adapted for such applications. Routine availability of NMR systems that incorporate multiple receivers has led to development of new types of NMR experiments. One such scheme named PANACEA allows unambiguous structure determination of small organic molecules from a single measurement and includes an internal field/frequency correction routine. It does not require the conventional NMR lock system and can be recorded in pure liquids. Furthermore, long-range spin-spin couplings can be extracted from the PANACEA spectra and used for three-dimensional structure refinement. In bio-molecular NMR, multi-receiver NMR systems are used for simultaneous recording of H-1 and C-13 detected multi-dimensional spectra. For instance, the 2D (HA)CACO and 3D (HA)CA(CO)NNH experiments can be recorded simultaneously in proteins of moderate size (up to 30 kDa). The multi-receiver experiments can also be used in combination with the fast acquisition schemes such as Hadamard spectroscopy, computer optimized aliasing and projection-reconstruction techniques. In general, experiments that utilize multiple receivers provide significantly more information from a single NMR measurement as compared to the conventional single receiver techniques.