Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1804226 | Journal of Magnetism and Magnetic Materials | 2007 | 9 Pages |
Abstract
For magnetic immunoassay applications, a novel magnetic reader for quantification of magnetic particle concentrations has been developed. Upon magnetic excitation at two distinct frequencies incident on the sample, the response signal generated at a sum frequency is detected. The low-frequency field component periodically drives the magnetic particles into saturation, which is probed by the high-frequency field. The appearance of frequency mixing lines is highly specific to the nonlinearity of the superparamagnetic particles’ magnetization. The optimization of field coils, differential pickup coil, preamplifier, demodulators and filters are discussed. The output signal is linear for four orders of magnitude in iron concentration.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Hans-Joachim Krause, Norbert Wolters, Yi Zhang, Andreas Offenhäusser, Peter Miethe, Martin H.F. Meyer, Markus Hartmann, Michael Keusgen,