System Combines Capillary Electrophoresis And NMR Spectroscopy

July 06, 1998

CHAMPAIGN, Ill. -- By using micro-electromechanical systems (MEMS) technology, researchers at the University of Illinois have developed a chip-based analytical system that combines capillary electrophoresis and nuclear magnetic resonance (NMR) spectroscopy. Integrated microfluidic-NMR systems could have important applications in a wide variety of combinatorial chemistry areas -- such as drug discovery -- and might facilitate the development of desktop NMR spectrometers.

"Capillary electrophoresis and NMR spectroscopy have competing design goals, but by integrating them with MEMS technology we can maximize the performance of both systems," said David Beebe, a professor of electrical and computer engineering and a researcher at the university's Beckman Institute for Advanced Science and Technology. "By using very small channels and samples, we can do high-performance capillary electrophoresis separations. And by performing those separations multiple times, we can collect a large enough sample to do NMR spectroscopy."

Beebe and U. of I. colleagues Richard Magin, Jonathan Trumbull and Ian Glasgow fabricated and tested two microfluidic-NMR devices. In the first device, designed as a proof of concept, the microfluidic channels were built from layered polyimide. In the second device, the channels -- or capillaries -- were etched into glass wafers. In both devices, the single-turn, planar NMR coils were formed from evaporated layers of chromium and copper.

"Although planar coils are less sensitive than solenoidal coils, they are easily integrated into batch-fabricated analytical devices," Beebe said. "The use of MEMS fabrication techniques allows precise control over the geometric parameters and materials that are so important to the performance of NMR microcoil detection. This allows one to more easily optimize the performance."

In order to optimize the weak signal received from small sample volumes, it is very important that the NMR coil does not disrupt the uniformity of the static magnetic field. By tuning the thickness of the evaporated metal layers, Beebe and his colleagues can make the coil transparent to the magnetic field, thus preventing any perturbations in the field.

"By shrinking the sample size to the nanoliter range, the volume over which the magnetic field must be uniform is also significantly reduced," Beebe said. "This should allow either a smaller -- and less expensive magnet -- to be used, or multiple spectrums to be taken in parallel in a conventional magnet, thereby multiplying throughput. With the large initial expenditure for a high-field superconducting magnet and the associated cost of ownership, these benefits are significant with small samples."The researchers described their microfluidic-NMR system and presented preliminary results at the Solid-State Sensor and Actuator Workshop, held June 7-11 at Hilton Head Island, S.C.


University of Illinois at Urbana-Champaign

Related Magnetic Field Articles from Brightsurf:

Investigating optical activity under an external magnetic field
A new study published in EPJ B by Chengping Yin, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China, aims to derive an analytical model of optical activity in black phosphorous under an external magnetic field.

Magnetic field and hydrogels could be used to grow new cartilage
Instead of using synthetic materials, Penn Medicine study shows magnets could be used to arrange cells to grow new tissues

Magnetic field with the edge!
This study overturns a dominant six-decade old notion that the giant magnetic field in a high intensity laser produced plasma evolves from the nanometre scale.

Global magnetic field of the solar corona measured for the first time
An international team led by Professor Tian Hui from Peking University has recently measured the global magnetic field of the solar corona for the first time.

Magnetic field of a spiral galaxy
A new image from the VLA dramatically reveals the extended magnetic field of a spiral galaxy seen edge-on from Earth.

How does Earth sustain its magnetic field?
Life as we know it could not exist without Earth's magnetic field and its ability to deflect dangerous ionizing particles.

Scholes finds novel magnetic field effect in diamagnetic molecules
The Princeton University Department of Chemistry publishes research this week proving that an applied magnetic field will interact with the electronic structure of weakly magnetic, or diamagnetic, molecules to induce a magnetic-field effect that, to their knowledge, has never before been documented.

Origins of Earth's magnetic field remain a mystery
The existence of a magnetic field beyond 3.5 billion years ago is still up for debate.

New research provides evidence of strong early magnetic field around Earth
New research from the University of Rochester provides evidence that the magnetic field that first formed around Earth was even stronger than scientists previously believed.

Massive photons in an artificial magnetic field
An international research collaboration from Poland, the UK and Russia has created a two-dimensional system -- a thin optical cavity filled with liquid crystal -- in which they trapped photons.

Read More: Magnetic Field News and Magnetic Field Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to