Patent ID: 7781228

Claim:
A method for detecting whether an analyte is present in a sample using magnetic resonance, the method comprising: applying a first magnetic field to a sample comprising a known liquid and material to be analyzed; applying a second magnetic field within at least one region of the sample such that magnetic resonance signals of the known liquid in the at least one region are different from magnetic resonance signals of the liquid exterior to the at least one region, wherein the second magnetic field is created by a nanoparticle associated with an affinity material; binding the analyte to the affinity material in the at least one region so as to inhibit spin-spin relaxation in the known liquid, thereby causing an increase in T 2 of the known liquid; exciting magnetic resonance signals from the known liquid while the analyte is in the at least one region; and determining the presence of the analyte by measuring the increase in T 2 of the known liquid.