Double-quantum filtered rotational-echo double resonance

The homonuclear scalar coupling of a directly bonded C-13-C-13 pair has been used to create a double-quantum filter (DQF) to remove the natural-a bun dance C-13 background in C-13{N-15} rotational-echo double-resonance (REDOR) experiments. The DQF scalar and REDOR dipolar evolution periods are coincident which is important for sensitivity in the event of weak C-13-N-15 dipolar coupling. Calculated and observed C-13{N-15} DQF-REDOR dephasings were in agreement for a test sample of mixed recrystallized labeled alanines. Glycine metabolism in a single uniform-N-15 soybean leaf labeled for 6 min by (CO)-C-13, was measured quantitatively by C-13{N-15} DQF-REDOR with no background interferences. (c) 2006 Elsevier Inc. All rights reserved.