Category Archives: ODNP

X-Band ODNP Resonator

High-Resolution ODNP Spectroscopy

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Related Product:  X-Band Microwave Source for ODNP

Overhauser DNP Spectroscopy

Overhauser Dynamic Nuclear Polarization (ODNP) enhanced NMR spectroscopy at 9 GHz (0.35 T, 15 MHz 1H NMR frequency) is a powerful method for site-specific studies of hydration dynamics at or near bio-macromolecules, membrane proteins, or other solid/liquid interfaces [1, 2]. In addition ODNP can be used to enhance the signal intensity in low-field NMR spectroscopy. Although the method has been known since the 1960s, it has just recently been successfully applied in structural biology and material science. The unique instrumentation requirements had previously limited the application of ODNP-enhanced NMR spectroscopy, specifically the lack of commercially available microwave sources and DNP resonators.

Upgrade your existing EPR Spectrometer

Unlike high-field DNP-enhanced solid- state NMR experiments, ODNP experiments at 9 GHz do not require a large superconducting NMR magnet or a high-power/high-frequency microwave source such as a gyrotron. In fact, any X-band EPR spectrometer can be easily upgraded with Bridge12 products for ODNP spectroscopy.

A turn-key ODNP resonatorfor your research

The Bridge12 ODNP resonator is compatible with any commercial or home-built X-band EPR spectrometer and can be installed just like any other resonator. The position of the integrated NMR coil is optimized to minimize interference with the microwave electromagnetic fields to achieve a high-Q resonator. This results in a high conversion factor and minimizes sample heating, even when using very high microwave power.

High conversion factor, minimal sample heating

The Bridge12 ODNP resonator is based on a dielectric resonator with a conversion factor > 3 G/√W and a loaded Q > 4000. Little microwave power is required to fully saturate the EPR signal. This is especially important for sample with high dielectric losses (e.g. water), to minimize the microwave induced sample heating. The sample is loaded either into a quartz sample tube (2 mm OD, 1 mm ID) or into a small sample capillary (0.84 mm OD, 0.6 mm ID).

X-Band ODNP spectrum of ethyl crotonate

Observe 1H or 19F or any nucleus you desire

The Bridge12 ODNP resonator has an integrated saddle coil with a single channel NMR circuit. Depending upon your application, the probe can be tuned to observe 1H, 19F, 2H, 13C or any other nucleus you are interested in.

Technical Specifications

  • X-Band Dielectric resonator(unloaded Q ~ 6900)
  • NMR Frequency: 14.5 +/- 0.5 MHz(other frequencies available).
  • Typical pulse length 1 us @ 10 W RF power
  • Maximum Sample Diameter: 2mm
  • Probe requires flow of clean, dry air (> 5 lpm)

Literature

[1] Franck, J.M., et al., Quantitative cw Overhauser Effect Dynamic Nuclear Polarization for The Analysis of Local Water Dynamics, Prog. Nucl. Magn. Reson. Spectrosc., 2013, 74(0), p. 33-56.

[2] Kaminker, I., Barnes, R., Han, Songi, Overhauser Dynamic Nuclear Polarization Studies on Local Water Dynamics, Meth. Enzym., 2015, 564, p. 457-483.

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OpenVnmrJ for ODNP Spectroscopy

Control single-board NMR spectrometers with OpenVnmrJ

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Related Product:  X-Band Microwave Source for ODNP

Overhauser DNP Spectroscopy

Overhauser enhanced Dynamic Nuclear Polarization (ODNP) spectroscopy in general requires a microwave source, an ODNP resonator and an NMR spectrometer. Low-field ODNP spectroscopy is typically performed at a magnetic field of 0.35 T, corresponding to an NMR frequency of ~15 MHz for protons. While many laboratories rely on home-built ODNP equipment, they often use a commercial (high-field) NMR spectrometer to record the NMR spectrum. However, these spectrometers come with significant overhead and are no cost-effective solutions to ODNP resulting in a large, unnecessary investments.

An ODNP Microwave Source with Integrated NMR Spectrometer

ODNP experiments performed at 0.35 T require an NMR spectrometer operating at 15 MHz to observe protons. A single-board NMR spectrometer such as the RadioProcessor Board (SpinCore Technologies, Inc., Gainesville, FL USA) is a cost-effective solution and sufficient for most ODNP experiments. This integrated NMR spectrometer is now available as an additional option for our Microwave Power Source (Bridge12 MPS).

OpenVnmrJ

OpenVnmrJ for ODNP

Many researchers that are interested in ODNP spectroscopy come out of the NMR community but are often unfamiliar with the additional microwave equipment. In collaboration with Open VnmrJ Solutions, the team at Bridge12 Technologies, Inc. has developed a variant of OpenVnmrJ that is tailored towards ODNP spectroscopy to lower the entry barrier.

OpenVnmrJ is the Open Source variant of the highly successful VnmrJ 4.2 acquisition and processing software that many Varian/Agilent NMR users are familiar with. It offers the benefits of a state-of-the-art NMR acquisition and processing software, while maintaining the required flexibility to control auxiliary equipment such as the microwave source. The specific version of OpenVnmrJ and its functions to operate a single-board NMR spectrometer are released as Open Source to make it available to entire research community. OpenVnmrJ is the Open Source version of VnmrJ version 4.2. In 2015, Agilent agreed to transfer the copyright of VnmrJ 4.2 to the University of Oregon. The software is available through the OpenVnmrJ project hosted on GitHub.

If you would like to receive more information on OpenVnmrJ and its support of single-board NMR spectrometers do no hesitate to contact us a info@bridge12.com.

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X-Band ODNP Probe

Large NMR Enhancements for Aqueous Samples

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Related Product:  X-Band Microwave Source for ODNP

Overhauser DNP Spectroscopy

Microwave resonator tuning (Varian TE102) with ODNP probe installed.

Overhauser Dynamic Nuclear Polarization (ODNP) enhanced NMR spectroscopy at 9 GHz (0.35 T, 15 MHz 1H NMR frequency) is a powerful method for site-specific studies of the accessibility and translational dynamics of water molecules at or near bio-macromolecules, membrane proteins, or other interfaces such as polymer/solvent interfaces [1, 2]. Although the method has been around since the 1960s, it has just recently been successfully applied in structural biology and material science. The unique instrumentation requirements had previously limited the application of ODNP-enhanced NMR spectroscopy, specifically the lack of commercially available microwave sources and DNP probes that are compatible with existing EPR instrumentation.

Upgrade your existing EPR Spectrometer

Unlike high-field DNP-enhanced solid- state NMR experiments ODNP experiments 9 GHz do not require a large superconducting NMR magnet or a high-power/high-frequency microwave source such as a gyrotron. In fact, any home-built or commercially available X-band EPR spectrometer, instruments that can be found in many academic research institutes, can be easily upgraded with Bridge12 products to do ODNP specroscopy.

 

1H ODNP enhancements of 4-amino TEMPO in Water

A turn-key ODNP probe for your research

The Bridge12 ODNP probe can be easily installed in a conventional X-band EPR cavity (e.g. Bruker 4102ST or Varian E231) and it comes with all necessary adapter parts to mount the probe. The positions of the NMR coil wires are optimized and the Q of the EPR cavity is only minimally affected. This conserves the high conversion factor of the EPR probe and minimizes sample heating even when using very high microwave power.

Change the sample, not the probe

The Bridge12 ODNP probe has a simple and convenient system to change the sample. Once the probe is mounted inside the EPR cavity and its position is optimized the probe will stay inside the EPR cavity and the probe does not have to be removed to change the sample. The sample can be loaded either into a quartz sample tube (2 mm OD, 1 mm ID) or into a small sample capillary (0.84 mm OD, 0.6 mm ID). The probe comes with sample holders for both options.

19F ODNP enhancement of 4-amino TEMPO in 2,2,2 trifluoroethanol

1H ODNP enhancements of 4-amino TEMPO in WaterObserve 1H or 19F or any nucleus you desire

The Bridge12 ODNP probe is a single channel NMR probe. Depending on your application the probe can be tuned to observe 1H, 19F, 2H, 13C or any other nucleus you are interested in.

 

 

 

 

 

ODNP Enhancement Profile of 4-amino Tempo in Water

1H ODNP Enhancement Profile

All RF tuning elements are conveniently located at the front of the probe. That makes it very easy to tune the probe to a new frequency and for example DNP enhancement profiles are recorded in a very short amount of time.

 

 

 

 

 

 

Technical Specifications

  • Technical Specifications Operating NMR Frequency: 14.5 +/- 0.5 MHz (other frequencies available)
  • Sample Size: Probe works very well with 2 mm sample tubes (Wilmad 712-SQ-250 mm or 0.84 mm capillaries (e.g. VitroCom CV6084-Q).
  • Maximum sample diameter 2.5 mm. Probes for larger sample sizes (non aqueous) are available.
  • Sample holder and probe mounts included.
  • Probe requires EPR cavity, e.g. Bruker 4102ST (TE102), 4119HS, 4122HSQE or ER4123D (TE011-like), or Varian E231 (TE102) for X-Band operation (Other frequencies available)
  • Unloaded resonator Q with probe installed: > 3100 For optimum performance probe requires flow of clean, dry air (> 5 lpm)

[1] Franck, J.M., et al., Quantitative cw Overhauser Effect Dynamic Nuclear Polarization for The Analysis of Local Water Dynamics, Prog. Nucl. Magn. Reson. Spectrosc., 2013, 74(0), p. 33-56.

[2] Kaminker, I., Barnes, R., Han, Songi, Overhauser Dynamic Nuclear Polarization Studies on Local Water Dynamics, Meth. Enzym., 2015, 564, p. 457-483.

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Microwave Source for X-Band ODNP Experiments

Microwave Source for ODNP-Enhanced NMR Spectroscopy

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Related Product: X-Band ODNP Probe

Overhauser DNP Spectroscopy

Bridge12 X-Band microwave source for ODNP experiments

Overhauser Dynamic Nuclear Polarization (ODNP) enhanced NMR spectroscopy at 9 GHz (0.35 T, 15 MHz 1H NMR frequency) is a powerful method for site-specific studies of the accessibility and translational dynamics of water molecules at or near bio-macromolecules, membrane proteins, or polymer/solvent interfaces [1,2]. Although the method has been in practice since the 1960s, it has just recently been successfully applied in structural biology and material science. The unique instrumentation requirements previously limited the application of ODNP-enhanced NMR spectroscopy, specifically the lack of commercially available microwave sources and DNP probes that are compatible with existing EPR instrumentation.

Upgrade any existing EPR Spectrometer

Unlike high-field DNP-enhanced solid-state NMR experiments, ODNP -enhanced NMR spectroscopy at 9 GHz does not require a large superconducting NMR magnet or a gyrotron as the microwave source. In fact, any commercially availabe or home-built X-band EPR spectrometer, often found in academic spectroscopy facilities, can be easily upgraded with ODNP capabilities.

A turn-key microwave source for you to focus on your research

The Bridge12 MPS 9 GHz is an easy-to-use X-band microwave source for ODNP spectroscopy. The maximum output power of commercially available, state-of-the-art EPR spectrometer is typically limited to < 300 mW, which is insufficient to drive the ODNP effect into saturation.

The Bridge12 MPS is a simple add-on for existing EPR spectrometers and can deliver up to 10 W of microwave power to the sample. The system features easy-to-use front panel operation, a concise design, and several failsafe features to protect your sample and your EPR instrumentation. You don’t have to be an expert in microwave technology to operate this system. Instead of troubleshooting home-built instrumentation, keep the focus on your research. Simply set the correct microwave frequency and output power, enable the microwave output, and start recording ODNP-enhanced NMR spectra. For more advanced users, the system features an optional external trigger to modulate the microwave power directly from the NMR console, and a USB interface for deeper integration of the source into the target application.

Easy to operate user interface

The Bridge12 MPS features a simple and concise user interface. A large, five inch front panel display is designed to show only the important values in an easy-to-read font size, even from a distance. Users can switch between the default screen and an advanced screen for more operation parameters.

A modular platform with many additional options

The Bridge12 MPS has a modular design, which can be upgraded with various features. The unit has a front panel SMA breakout for users who would like to add external components such as fast microwave switches, or mixers for pulse shaping (e.g. AWG).

The system has an integrated power detector to constantly monitor the forward and reflected microwave power and also disables the microwave power once the reflected power exceeds a certain level. Additional tuning/matching features can be added to display the cavity tuning in real time.

Five additional digital input/output lines can be individually programmed for user-specific functions. For example, the instrument can be configured to run through a predefined power schedule, to fully automate ODNP experiments.

ODNP connection kit

Bridge12 offers a connection kit for seamlessly integrating the ODNP microwave source and probe into existing EPR instrumentation. This allows a user to simply switch back and forth between EPR and DNP operation. The kit includes a waveguide switch that can be operated manually or automatically to ensure the safety of your EPR equipment.

Integrated NMR spectrometer

The system can be equipped with a single-channel, compact NMR spectrometer. The system is entirely controlled using OpenVnmrJ. For more information take a look here.

The Bridge12 MPS for ODNP-enhanced NMR spectroscopy is also available for experiments at K (24 GHz) and Q (35 GHz) band.

[1] Franck, J.M., et al., Quantitative cw Overhauser effect dynamic nuclear polarization for the analysis of local water dynamics. Prog. Nucl. Magn. Reson. Spectrosc., 2013. 74(0): p. 33-56.

[2] Franck, J. M., and Songi Han. “Overhauser Dynamic Nuclear Polarization for the Study of Hydration Dynamics, Explained.” In Methods in Enzymology, 615:131–75.

Technical Specifications

  • Frequency Range: 8.5 – 11.5 GHz (also available for Q and K-band spectrometers)
  • Maximum Output power: 5 or 10 W (cw). Continuous attenuation in steps of 0.01 dB
  • Operation: Front Panel operation. Digital interface (USB) for remote operation (optional)
  • TTL pulse modulation (optional): 100 ns minimum pulse length, 50 % minimum duty cycle (shorter pulses available).
  • Temperature monitor and safety switch to prevent overheating of the amplifier.
  • System size (W x H x D): 12 x 7 x 14 (inch), 30.5 x 17.8 x 35.6 (cm)
  • System weight: 3.3 lbs (1.5 kg)
  • Input power: 110 – 220 V (50/60 Hz)

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If you have questions about our instrumentation or how we can help you, please contact us.