Low-power cross polarization in fast magic-angle spinning NMR experiments
نویسندگان
چکیده
0009-2614/$ see front matter 2008 Elsevier B.V. A doi:10.1016/j.cplett.2008.11.089 * Corresponding author. E-mail addresses: [email protected], [email protected] gmx.ch (B.H. Meier). We describe a low-power approach for heteronuclear cross-polarization (CP) at high magic-angle spinning (MAS) frequencies. It is based on second-order CP at the n = 0 Hartmann–Hahn condition. The mechanism for the polarization transfer in the low-power CP experiment relies on second-order cross terms between homonuclear and heteronuclear dipolar couplings. At a MAS frequency of 65 kHz, rf-field amplitudes below 10 kHz are sufficient to efficiently transfer polarization from H to C. The low-rf field requirements of this approach make it well suited for the investigation of proteins and other temperature-sensitive samples without the risk of sample heating and degradation. 2008 Elsevier B.V. All rights reserved.
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