Quantitative cross-polarization NMR spectroscopy in uniformly 13C-labeled solids

A novel QUantitative Cross Polarization (QUCP) scheme is proposed, which can be applicable for quantitative measurement of cross-polarization magic angle spinning (CP/MAS) spectroscopy in solid-state NMR. In this QUCP experiment, the combination of CP and broadband homonuclear recoupling technique (DARR) ‘homogenizes’ the non-uniform CP-prepared polarizations of dilute spins so that quantitative CP/MAS spectra can be obtained. Not only are all magnetizations enhanced uniformly by QUCP scheme, but also is the experimental time reduced greatly. In addition, the uniform enhancement is independent of the experimental parameters of cross-polarization. The present scheme is applicable for systems containing carbonyl, aromatic, and aliphatic carbons or some of these groups.