Powder patterns and sideband patterns have different strengths when it comes to using them to determine chemical shift parameters. Here, we show that chemical shift parameters can be determined with high accuracy by analysing the correlation pattern from a 2D experiment which correlates a powder pattern in the indirect dimension with a sideband pattern in the direct dimension. The chemical shift parameters so determined have greater accuracy than those obtained by analysing a sideband or powder pattern alone, for the same signal-to-noise ratio. This method can be applied for both resolved correlation patterns and to cases where two components share similar isotropic chemical shifts. The methodology is demonstrated in this paper, both theoretically and experimentally, on the (31)P signals of the bis-phosphonate drug, pamidronate.
Copyright (c) 2008 John Wiley & Sons, Ltd.