SELECTIVE MAGNETIC-RESONANCE CORRELATION SPECTROSCOPY WITH IN-PHASE MULTIPLETS

New two-dimensional nuclear magnetic resonance (NMR) correlation methods are presented which allow one to obtain selected high-resolution multiplets where all signals have positive pure absorption peak shapes. The multiplets do not suffer from any cancellation effects, and their fine structure consists of a simple superposition of square patterns in two-dimensional frequency domain that can be readily interpreted. The intensities of multiplets obey the same simple binomial rules as those in conventional one-dimensional NMR spectra. The methods rely on a transfer of in-phase magnetization during a doubly selective irradiation period. Complications arising from undesirable coherence-transfer phenomena are eliminated either by removing antiphase terms while leaving the in-phase components unaffected or by a combination of spin-locking of in-phase terms and elimination of antiphase terms.