title: Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100 kHz MAS.
abstract: Two-dimensional (1)H{(13)C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in (1)H dimension without resorting to (1)H-(1)H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. The HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.
authors.affiliation: JEOL Resonance Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan. Electronic address: yunishiy@jeol.co.jp.
authors.forename: Y
authors.initials: Y
authors.lastname: Nishiyama
authors.affiliation: U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA.
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: JEOL Resonance Inc., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Malon
authors.affiliation: U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA.
authors.forename: D
authors.initials: D
authors.lastname: Singappuli-Arachchige
authors.affiliation: U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA.
authors.forename: I I
authors.initials: II
authors.lastname: Slowing
authors.affiliation: U.S. DOE Ames Laboratory, Ames, IA 50011-3020, USA; Department of Chemistry, Iowa State University, Ames, IA 50011-3020, USA. Electronic address: mpruski@iastate.edu.
authors.forename: M
authors.initials: M
authors.lastname: Pruski
keywords: HMQC; HSQC; Indirect detection; Mesoporous silica nanoparticles; Ultrafast MAS