# US 5,350,697 A · Scattered light detection apparatus

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- Number: US 5,350,697 A
- Document ID: US5350697A
- Status: Granted
- Kind: A
- Application number: 07/574,184
- Filed: 1990-08-28
- Granted: 1994-09-27
- Earliest claimed: 1990-08-28
- Assignees: Akzo N.V.
- Inventors: C. Hermas Swope; John G. Link; Jones M. Hyman
- Web page: https://patentgrep.com/patent/US5350697A

## CPC

- G01N 21/47: Scattering, i.e. diffuse reflection (G01N21/25, G01N21/41 take precedence {G01N21/55 takes precedence})
- G01N 33/54373: {involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings}
- G01N 2021/4707: {Forward scatter; Low angle scatter}
- G01N 2021/4709: {Backscatter}
- Y10S 435/808: Optical sensing apparatus
- Y10S 436/805: Optical property
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

An apparatus in which scattered light is measured, said apparatus having a light source aligned to direct illumination toward an interface between a sample container and an aqueous solution at an angle less than the critical angle. A detector to measure the scattered light is located at a place outside the envelope of the critical angle.

## Claims

### Claim 1

An apparatus for conducting an immunoassay to detect an analyte ligand using a ligand labelled with light scattering particles or a first ligand binding partner labelled with light scattering particles in an aqueous solution, comprising:
(a) a receiving means for receiving and holding an aqueous solution, said receiving means coated with a reagent containing a second ligand binding partner for said analyte ligand or said ligand labelled with light scattering particles and including at least one portion consisting of an optically transmissive material, said material having a refractive index greater than that of said aqueous solution;
(b) illumination means for providing light to an interface formed between said optically transmissive material portion of the receiving means and an aqueous solution in said receiving means, wherein the light is directed to strike the interface at an angle less than the critical angle; and
(d) photodetector means for receiving light scattered from said interface at an angle equal to or greater than the critical angle by bound light scattering particles.

### Claim 2 (depends on 1)

The apparatus as recited in claim 1, wherein said photodetector means detects forward scattered light.

### Claim 3 (depends on 1)

The apparatus as recited in claim 1, wherein said receiving means is a sample container.

### Claim 4 (depends on 1)

The apparatus as recited in claim 1, wherein said receiving means is a cuvette.

### Claim 5 (depends on 1)

The apparatus as recited in claim 1, wherein said illumination means is a laser.

### Claim 6 (depends on 1)

The apparatus as recited in claim 1, further comprising an alignment means for positioning said optically transmissive material portion in a fixed relationship to the illumination means, wherein the light is directed to strike the interface at an angle less than the critical angle by said alignment means.

### Claim 7 (depends on 6)

The apparatus as recited in claim 6, wherein said alignment means is a prism.

### Claim 8 (depends on 1)

The apparatus as recited in claim 1, wherein said receiving means is a slide with said aqueous solution on one surface of said slide, and wherein said illumination is directed through said slide from the other side.

### Claim 9 (depends on 1)

The apparatus as recited in claim 1, wherein said photodetector means detects back scattered light.