Nuclear magnetic resonance in microfluidic environments using inductively coupled radiofrequency resonators

Utz, Marcel; Monazami, Reza

doi:10.1016/j.jmr.2009.01.028

Cited by 28 publications

(35 citation statements)

References 38 publications

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“…Equation [18] shows that the efficiency is close to 1 in the overcoupling regime: k k c . As k is of the order of the square root of the ratio of the coil's volumes V 1 and V 2 , the condition k k c is not very stringent and is realized if:…”

Section: Model Circuit and Definitionsmentioning

confidence: 91%

“…Resonant inductive coupling to a resonator has been introduced by Diodato et al (36) in the context of EPR. Applications to NMR and MRI have recently followed (1,(16)(17)(18). Here we present extensively an analysis to fully determine optimized performance for microNMR studies.…”

Section: Coupling To Rotating Coils By Resonant Inductive Couplingmentioning

confidence: 99%

“…In the solid state, the application of static microcoils in nonspinning (11) and spinning samples (12)(13)(14)(15) has also received great attention. Several authors have recently proposed the use of inductive coupling between the coil of any standard NMR probe and a microcoil (1,(16)(17)(18)(19). This wireless coupling permits for easy sample and coil rotation inside conventional rotors as a way to enhance the filling factor and thus the sensitivity of limited-size solid samples (1,20,21).…”

Section: Introductionmentioning

confidence: 99%

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NMR signal detection using inductive coupling: Applications to rotating microcoils

Jacquinot

Sakellariou

2011

Concepts Magnetic Resonance

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Sensitivity in solid-state nuclear magnetic resonance can be improved by the use of rotating microcoils (1). The connection to the rest of the electronics is performed through resonant inductive coupling. This mode of detection of nuclear induction has major advantages as it provides a wireless way to obtain extremely high radio-frequency amplitudes per unit current under sample rotation and thus improved sensitivity for size-limited samples. We review the circuit electronics and discuss experimental optimization of the probe and coil parameters. We also present alternative geometries for coupling between rotating coils and we explicitly calculate the signal enhancement. Two practical cases are presented, namely a standard magic angle sample spinning probe and a double sample rotation probe. We conclude with a theoretical discussion about the limits of detection attainable with coil miniaturization.

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Section: Model Circuit and Definitionsmentioning

confidence: 91%

Section: Coupling To Rotating Coils By Resonant Inductive Couplingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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NMR signal detection using inductive coupling: Applications to rotating microcoils

Jacquinot

Sakellariou

2011

Concepts Magnetic Resonance

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“…However, in certain cases, as for example, for bench‐top NMR spectrometers, the detector is non‐changeable, and therefore, it is not feasible to replace such detector with one that exhibits a higher filling factor for small samples. A very good solution to such a problem is the use of a passive LC resonator 19. The inductor L c , in this case, is designed to achieve maximum filling factor of the sample, while the capacitor C c is chosen in a way to make the L c resonate at the Larmor frequency C c = 1/( L c ω 2 ).…”

Section: Theorymentioning

confidence: 99%

“…(ii) The wireless transfer of energy (signal) from an MR detector, which is enabled by placing a pick‐up coil which is wired to the spectrometer in close proximity to a non‐wired MR detector. The signal recorded by the MR detector is transferred via inductive coupling to the spectrometer and is typically used to access samples within restricted areas,7, 8, 9, 10, 11, 12, 13 to locally enhance the signal‐to‐noise ratio (SNR),14, 15, 16 or to improve the handling comfort of MR probes 17, 18, 19, 20, 21, 22…”

Section: Introductionmentioning

confidence: 99%

A comparison of Lenz lenses and LC resonators for NMR signal enhancement

Jouda

Kamberger

Leupold

et al. 2017

Concepts Magn Reson

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High signal‐to‐noise ratio (SNR) of the NMR signal has always been a key target that drives massive research effort in many fields. Among several parameters, a high filling factor of the MR coil has proven to boost the SNR. In case of small‐volume samples, a high filling factor and thus a high SNR can be achieved through miniaturizing the MR coil. However, under certain circumstances, this can be impractical. In this paper, we present an extensive theoretical and experimental investigation of the inductively coupled LC resonator and the magnetic Lenz lens as two candidate approaches that can enhance the SNR in such circumstances. The results demonstrate that the narrow‐band LC resonator is superior in terms of SNR, while the non‐tuned nature of the Lenz lens makes it preferable in broadband applications.

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