The invention discloses a ferroferric
oxide, gold, internal
label and
gold core-shell
nanoparticle and a preparation method thereof. Ferroferric
oxide is used as a main body, nano-particles which take 16-20 nm gold nano-particles as cores, take sulfydryl molecules with
benzene rings as internal standards and have the gold shell thickness of 35-40 nm are adsorbed on the surface of the ferroferric
oxide, the overall particle size of the ferroferric oxide nano-particles is 200-460 nm, and the particle size of ferroferric oxide balls is 160-400 nm; the method comprises the following steps: uniformly dissolving
ferric chloride,
sodium acetate and
polyethylene glycol in
ethylene glycol according to a
mass ratio of (1-2.7): (0.15-0.72): (0.5-2.3), heating to 200 DEG C, keeping the temperature for 8-72 hours, and naturally cooling to
room temperature; and putting the product into a
drying box, and
drying at 60 DEG C. The method comprises the following steps: firstly, preparing Fe3O4 nano-particles, then carrying out
surface modification on the Fe3O4 nano-particles, adsorbing 16nm gold seeds to the surfaces of the Fe3O4 nano-particles, adding
internal standard molecules, and finally adding
ascorbic acid and
chloroauric acid to realize gold shell growth on the surfaces of the 16nm gold seeds. The material has the advantages of magnetic aggregation, easiness in separation and the like, and can be applied to the fields of
pesticide residue detection,
catalytic degradation, environment detection and analysis and the like based on an SERS (Surface Enhanced
Raman Scattering) technology.