Construção de uma sonda \textit{microslot} para Ressonância Magnética Nuclear
     Construction of a microslot probe for Nuclear Magnetic Resonance

Luís Guilherme Uhlig, Alexandre M. Souza

Resumo


Os experimentos de ressonância magnética Nuclear (RMN) possuem baixa sensibilidade, o que limita a utilização da técnica. Uma das abordagens para aumentar a sensibilidade do experimento é a miniaturização do circuito ressonador contido na sonda, com o desenvolvimento de microrressonadores. Este trabalho apresenta a construção de um circuito para uma sonda do tipo \textit{microslot} mediante o emprego da técnica de litografia com \textit{LASER}. Foram realizados experimentos para comparar o desempenho do \textit{microslot} com duas outras sondas comerciais do tipo sela. A sonda do tipo \textit{microslot} apresentou maior fator de eficiência, pois esta pode gerar um campo magnético mais intenso para uma dada potência elétrica. Também é mostrado que a resolução obtida com a sonda \textit{microslot} permite a observação de grupos químicos diferentes.

Palavras chave:  Microrressonador, \textit{microslot}, ressonância nuclear magnética.

Nuclear magnetic resonance experiments (NMR) have low sensitivity, which limits the usage of the technique. One approach to enhance the sensitivity of NMR experiments is the miniaturization of the resonant circuit contained in the probe, by developing microcoils or microresonators. This work presents the construction of a microslot probe using LASER lithography. Experiments were performed to compare the microslot probe and commercial saddle type probes. The microslot probe presented higher efficiency factor, since it can generate a more intense magnetic field for a given electrical power. We also show that the resolution obtained with the microslot probe allows the observation of different chemical groups.

Keywords: Microresonator, microslot, nuclear magnetic resonance.


Texto completo:

PDF

Referências


FUKUSHIMA, E.; textit{Experimental Pulse NMR - A Nuts and Bolts Approach"}, Addison-Weslea (1981).

FARRAR, T. C; BECKER E. D.; textit{Pulse and Fourier Transform NMR - Introduction to Theory and Methods}, Academic Press (1971).

MISPELTER, J; LUPU, M.; BRIGUET, A.; textit{NMR Probeheads for Biophysical and Biomedical Experiments}, Imperial College Press (2015).

BART, Jacob; textit{Stripline-based microfluidic devices for high-

resolution NMR spectroscopy}, Wöhrmann Print Service (2009).

WU, N; PECK, T. L.; WEBB, A. G.; MAGIN, R. L.; SWEEDLER, J. V;,textit{1H-NMR Spectroscopy on the Nanoliter Scale for Static and Online Measurements}, Anal. Chem., v. 66, n. 33, 3849-3857 (1994).

WEBB, A. G.; textit{Microcoil nuclear magnetic resonance spectroscopy}, Journal of Pharmaceutical and Biomedical Analysis, v. 38, n. 5, 892-903 (2005).

LACEY, M. E.; SUBRAMANIAN, R.; OLSON, D. L.; WEBB,, A. G; SWEEDLER, J. V; textit{High-Resolution NMR Spectroscopy of Sample Volumes from $1 nL$ to $10 mu$L}, Chemical Reviews, v. 99, n. 10, 3133-3152 (1999).

NARCOVWICZ, R; OGATA, H.; REIJERSE, E; SUTER, D.; textit{A cryogenic receiver for EPR}, Journal of Magnetic Resonance, n. 237, 79-84 (2013).

FRATILA, R. M.; VELDERS, A. H.; textit{Small-Volume Nuclear Magnetic Resonance Spectroscopy}, Annual Review of Analytical Chemistry, n. 4, 227-249 (2011).

YUE, C. P; textit{Physical Modeling of Spiral Inductors on Silicon}, IEEE Transactions on Electron Devices, v. 47, n. 3 (2000).

NARKOWICZ, R; SUTER, D.; STONIES, R.; textit{Planar microresonators for EPR experiments}, Journal of Magnetic Resonance, v. 175, n. 2, 275-284 (2005).

BAHNHOLZER, A; NARKOWICZ, R.; HASSEL, C.; MECKENSTOCK, R.; STIENEN, S.; POSTH, O; SUTER, D.; FARLE, M.; LINDNER, J.; textit{Visualization of spin dynamics in single nanosized magnetic elements}, Nanotechnology, v. 22, n. 29, 295713 (2011).

KALFE, A.; textit{Looking into living cell systems: Planar waveguide NMR detector hyphenated with a microfluidic device for the in vitro metabolomics of tumor spheroids}, Leibniz-Institut für Analytische Wissenschaften (2015).

KROJANSKI, H. G.; textit{Microslot NMR Probe for Metabolomics Studies}, Analytical Chemistry, n. 80, 8668-8672 (2008).

MAGUIRE, Y. G. E.; textit{Microslots: Scalable Electromagnetic Instrumentation}, Massachusetts Institute of Technology (2004).

MAGUIRE, Y.; textit{Ultra-small-sample molecular structure detection using microslot waveguide nuclear spin resonance}, Proceedings of the National Academy of Sciences, v. 104, n. 22, 8668-8672 (2007).