Patent ID: 9739700
Date: 2017-08-22
CPC Classifications: G01N

Claim:
1. A method for detecting nano-particles, comprising the following steps: (1) compressing a sample liquid to be detected into a sample liquid flow by hydrodynamic focusing using a sheath fluid, wherein the sample liquid flow contains nano-particles to be detected, and the nano-particles are essentially separated from each other and essentially flow in the same line in the sample liquid flow; (2) irradiating a measuring light to the sample liquid flow, wherein a single nano-particle in the sample liquid flow is irradiated by the measuring light for 0.1-10 ms, preferably 0.2-2 ms; (3) defining the region of the sample liquid flow subjected to irradiation of the measuring light as a detecting region, and collecting light signals emitted from the region irradiated by the measuring light via a lens imaging system, and allowing the light signals collected by the lens imaging system to pass through a field stop, so as to filter out the light signals outside the detecting region and enrich the light signals from the detecting region, the volume of the detecting region is 1-100 fL, preferably 10-100 fL, more preferably 10-30 fL; (4) subjecting the light signals enriched by the field stop to optoelectronic signal conversion, and acquiring the electrical signals of scattered light emitted from each nano-particle in the sample liquid flow, or the electrical signals of scattered light and fluorescent light emitted from each nano-particle in the sample liquid flow, the field stop is a photosensitive region of a photoelectric detector or an aperture diaphragm added in front of the photoelectric detector, the area of the photosensitive region or the aperture area of the aperture diaphragm is 50 to 5×10 (5) carrying out qualitative and/or quantitative analysis for the nano-particles according to the electrical signals.