One-dimensional pulse technique for detection of quaternary carbons

A one-dimensional pulse scheme employing pulsed field gradients for detecting only quaternary carbons is reported. This new scheme, referred to as PFG-QCD (pulsed field gradient quaternary carbon detection), suppresses primary, secondary and tertiary (CH3, CH2 and CH) carbons very efficiently by creating their antiphase magnetization and then either dephasing the antiphase magnetization using pulsed field gradients or by the introduction of proton decoupling to the antiphase carbon magnetization. The experimental results of the new technique also demonstrate that mis-setting of the parameters such as the tau delay and the pulse widths does not appreciably degrade the quality of the resultant spectrum. The proposed method provides spectra which are superior, in terms of suppression of unwanted protonated carbon signals, to the other editing methods and thus provides a useful alternative technique for routine applications. Copyright (C) 2001 John Wiley & Sons, Ltd.