Abstract: There is provided a method of detecting a change of a state of a liquid comprising the steps of: •providing a liquid detection medium (12) comprising a liquid and having a plurality of anisotropic magnetic particles suspended therein; •applying a modulated magnetic field across at least a portion of the liquid detection medium (12), wherein the magnetic field induces an alignment of the magnetic particles; •introducing electromagnetic radiation (22) into the liquid detection medium (12); •detecting a variable which is modulated by the applied magnetic field, wherein the variable is associated with the interaction of the electromagnetic radiation (22) with the magnetic particles and wherein the change in the state of the liquid causes a variation in the detected variable; and •correlating the variation in the detected variable with the change in the state of the liquid.

Abstract: There is provided a method of detecting a change of a state of a liquid comprising the steps of: • providing a liquid detection medium (12) comprising a liquid and having a plurality of anisotropic magnetic particles suspended therein; • applying a modulated magnetic field across at least a portion of the liquid detection medium (12), wherein the magnetic field induces an alignment of the magnetic particles; • introducing electromagnetic radiation (22) into the liquid detection medium (12); • detecting a variable which is modulated by the applied magnetic field, wherein the variable is associated with the interaction of the electromagnetic radiation (22) with the magnetic particles and wherein the change in the state of the liquid causes a variation in the detected variable; and • correlating the variation in the detected variable with the change in the state of the liquid.