(1)H- (31)P soft-HSQC pulse sequence specifically for detecting phosphomono- and diesters in biological samples.

PURPOSE: Phosphomono- and diesters (PME and PDE) are important metabolites that are potential biomarkers for a number of cancers. We designed a new NMR pulse sequence, i.e., (1)H-(31)P soft-heteronuclear single quantum correlation (HSQC), specifically for noninvasively detecting PME and PDE in biological samples.

PROCEDURE: The nonselective (1)H refocusing π pulses in the conventional heteronuclear single quantum correlation pulse sequence are replaced by selective π pulses. When the selective pulses are offset on the CH2O resonances, the homonuclear couplings between the NCH2 and CH2O protons are effectively removed, and the spectrum of PME and PDE is significantly enhanced.

RESULTS

The sensitivity of this pulse sequence has been demonstrated with milk and mouse brain samples. A soft-HSQC spectrum, where only PME and PDE signals appear, can be recorded from these biological samples in minutes with remarkably high signal-to-noise ratio.

CONCLUSION

This pulse sequence provides a new and quick method for in vivo studies of phosphorus metabolite in the human brain and other tissues for medical purposes.