GRADIENT SELECTION OF COHERENCES IN EXPERIMENTS WITH CARBON DETECTION

Coherence pathway selection with gradients in carbon-detected experime nts is demonstrated. Gradient selection (gs) offers excellent suppress ion of artifacts and unwanted magnetization, and in practice the signa l-to-noise ratio is at least as good as for the equivalent phase cycle d experiment. A selective gs-1D-C-13-COSY is used to correlate one car bon resonance with its neighbours. The gs-INADEQUATE is used to select multi-quantum coherences; this can be performed as a 1D or a 2D exper iment. Complete elimination oft, noise is obtained in the gs version o nly. Applications to labelled glucose, 3-phenylpropan-1-ol and natural abundance menthol are presented. Interference from high-frequency str ay radiation in the gradient cable is removed by inserting a low-pass filter between the gradient wiring and the probe.