Method of detection with a fluorescent labeling particle

A method of detecting a target substance, which comprises:

• mixing an analyte, a fluorescent labeling particle (A), and a dispersant (B) to form a complex by binding the fluorescent labeling particle and the dispersant via a target substance in the analyte,
• wherein the fluorescent labeling particle (A) comprises:
• a phase comprising a magnetic material,
• a phase comprising a fluorescent material which is constituted of a continuous phase formed of a transparent material including a silica and a dispersed phase formed of the fluorescent material, said phase is coating the phase comprising the magnetic material,
• a thermoresponsive polymer immobilized on the phase comprising a fluorescent material, and
• a binding substance having properties of binding with the target substance immobilized on the thermoresponsive polymer;
• and
• the dispersant (B) comprising a dispersant base and a binding substance having properties of binding with the target substance.