Shuttle DNP spectrometer with a two-center magnet.
A DNP set-up is described where a liquid sample is hyperpolarized by the electron-nucleus Overhauser effect in a field of 0.34 T and transferred to a field of 14.09 T for NMR detection. In contrast to a previous set-up, using two dedicated magnets for polarization and detection, a dedicated ferroshim system was inserted into the bore of a 14.09 T shielded cryomagnet to provide a homogeneous low-field region in the stray field above the magnetic center. After polarization in the low-field the sample is transferred to the high-field magnetic center within 40 ms by a pneumatic shuttle system. In our set-up a standard high-resolution inverse (1)H/(13)C selective probe was used for NMR detection and a homebuilt EPR cavity, operating in the TM(110) mode was used for polarisation. First experimental data are presented. We observed a maximum proton Overhauser enhancement of up to epsilon(HF) = -3.7 in the high-field position for a 5 mM 4-Oxo-TEMPO-D,(15)N (TEMPONE)/H(2)O sample. While this reproduces the DNP enhancement observed also in the old set-up, with the new set-up we observe enhancement on larger molecules that were impossible to enhance in the old set-up. Therefore, we can demonstrate for the first time Overhauser enhanced high resolution proton spectra of glucose and 2,2-dimethyl-2-silapentane-5-sulfonic acid sodium salt (DSS) in D(2)O, where the high resolution spectrum was acquired in the high-field position after polarizing the sample in the low-field.
Krahn
Alexander
A
Bruker BioSpin, Silberstreifen 4, D-76287 Rheinstetten, Germany.
Lottmann
Philip
P
Marquardsen
Thorsten
T
Tavernier
Andreas
A
Türke
Maria-Teresa
MT
Reese
Marcel
M
Leonov
Andrei
A
Bennati
Marina
M
Hoefer
Peter
P
Engelke
Frank
F
Griesinger
Christian
C
D017738:Alkanesulfonic Acids / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation* / Q000379:methods; D008280:Magnetics; D010880:Piperidines / Q000737:chemistry; D014216:Triacetoneamine-N-Oxyl / Q000737:chemistry; D014297:Trimethylsilyl Compounds / Q000737:chemistry
C528764:2,2,6,6-tetramethyl-1-piperidine; D017738:Alkanesulfonic Acids; D010880:Piperidines; D014297:Trimethylsilyl Compounds; C009580:3-(trimethylsilyl)propanesulfonic acid; D014216:Triacetoneamine-N-Oxyl; D005947:Glucose