โ Scribed by Xiaoling Wu; Shanmin Zhang; Xuewen Wu
No coin nor oath required. For personal study only.
A depolarization scheme for suppressing rigid protonatcd carbon-l 3 signals in CP MAS NMR is presented. The principle underlying the new scheme is not proton-carbon dipolar dephasing, but the depolarization of carbon-l 3. Because the carbon-13 magnetization is always locked by irradiation before the data acquisition, there is no additional phase distortion in the spectrum even for the surviving protonated carbon-l 3 signals. Compared with a variety of delayed decoupling schemes, the depolarization scheme gives a spectrum which has the least distortion in the relative intensity of individual non-protonated carbon-13 lines.
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