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Quartz Crystal Microbalance (QCM)

The Quartz crystal microbalance (QCM) provides mass and structural information on molecular layers that form on the surface of a sensor. Molecular adsorption and interactions can be monitored in real time under a variety of conditions. Sensors can be chemically modified to produce a range of surfaces for study. QCM is sensitive to very small changes in mass, down to 2 ng cm-2.

Up to four flow cells can be used in parallel or series configurations, and electrochemical measurements can be made simultaneously using a modified unit.

cogsHow does it work?

The QCM monitors resonant frequencies and the dissipation of these signals in a quartz chip. The sensor chip can be coated with a variety of substrates, most commonly gold, which can be chemically funcionalised. A solution of the substance of interest is flowed over the chip in a cell at constant temperature. Molecules which become attached to the surface of the chip cause the resonant frequencies and dissipations to change.

For thin and rigid films the Sauerbray equation can be used to calculate directly the mass of sample that has become attached to the surface. For soft layers, a viscoelastic modelling process can be used to determine the thickness and elastic properties of the film.

Applications:

Thin film thickness monitoring; electrochemistry; biotechnology; interactions of DNA and RNA; molecular recognition; adhesion of cells; liposomes and proteins; formation of biofilms; lipid membranes; polymer coatings; reactive surfaces; sensors; self-assembled monolayers; surfactant research; drug research.

Sample handling requirements:

Solution and sensor chip

Complementary techniques:

Ellipsometry

Warwick Capability:

Q-Sense QCM-D E4

Contact:

Dr Ian Hancox, 024 76 150380 email i dot hancox at warwick dot ac dot uk

qcm.jpg
Typical results:

Thiols on a gold sensor - click to enlarge

Status
Availability
green_tick.gif Warwick collect/analyse data
green_tick.gif Warwick collect data
 green_tick.gif Available to user with expertise/ contribution
 green_tick.gif Spare capacity for collaborative research
 

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