US 6,147,350 A · Spectroscopic residue detection system and method

Abstract

A spectroscopic detection system and method for quantitative measurements of non-volatile residues. A sample to be analyzed is spread out on the inside surface of a cup portion of a unique detector cup. The cup portion mates with a detector portion to create an enclosed reflecting volume. A small port in the detector portion permits entrance of light which diffusely reflects multiple times from the inside surface of the enclosed reflecting volume and which is partially absorbed by the sample depending on the spectral absorption characteristics of the sample. A light detector in the detector portion detects light after multiple reflections from the surfaces of the detector and cup portions and multiple passes through the sample on the surface of the cup portion. Light detected by the light detector is spectrally analyzed to determine the spectral characteristics of the sample. In a preferred embodiment of the present invention the light is infrared light, the diffusely reflecting volume is a sphere, the reflecting surface of the cup is a smooth hemispheric gold surface and the reflecting surface of the detector portion is a rough hemispheric gold surface. In this preferred embodiment light from a broad band infrared light source is directed through an interferometer system prior to entering the detector cup and signals from the light detector are Fourier analyzed along with mirror position data to determine absorption characteristics of the sample.

Claims27

Dependent claims

A residue detection system for spectroscopic analysis of non-volatile residues comprising:

A) a light source,
B) a detector cup comprising:
1) a detector portion comprising:
a) a light detector,
b) a structural element defining a detector portion inside surface and
c) a light port, and
2) a cup portion defining a cup portion inside surface, said cup portion inside surface defining a cup portion inside surface area, and containing a sample spread over at least half of said inside surface area, said cup portion being releasably attached to said detector portion such that said detector portion and said cup portion inside surfaces define an enclosed diffusely reflecting volume,
C) an optical train for directing light from said light source into said enclosed diffusely reflecting volume,
D) a processor for analyzing signals produced by said light detector to determine optical characteristics of said sample;
wherein said light detector in said detector portion detects light from said light source after multiple reflections from the surfaces of the detector and cup portions and multiple passes through the sample deposited on said cup portion inside surface.

7 more elements

A method of performing spectroscopic analysis utilizing a spectroscopic residue detection system for analysis of non-volatile residues comprising:

A) a light source,
B) a detector cup comprising:
1) a detector portion comprising:
a) a light detector,
b) a structural element defining a detector portion inside surface and
c) a light port, and
2) a cup portion defining a cup portion inside surface, said cup portion inside surface defining a cup portion inside surface area, said cup portion being releasably attachable to said detector portion such that when attached said detector portion and said cup portion inside surfaces define an enclosed diffusely reflecting volume,
C) an optical train for directing light from said light source into said enclosed diffusely reflecting volume,
D) a processor for analyzing signals produced by said light detector to determine optical characteristics of said sample;
said method comprising the steps of:
A) dissolving at least one contaminant in a volatile solvent,
B) depositing said contaminant containing solvent in said cup portion,
C) evaporating said volatile solvent to leave a sample of residue deposited on an area constituting at least half of the cup portion inside surface area,
D) attach said cup portion to said detector portion,
E) directing light into said detector cup,
F) processing signals from said detector to determine optical characteristics of said sample;
wherein said light detector in said detector portion detects light from said light source after multiple reflections from the surfaces of the detector and cup portions and multiple passes through the sample deposited on said cup portion inside surface.

14 more elements

Dependencies are inferred from the claim text.

Spectroscopic residue detection system and method

Life of this patent

Spectroscopic residue detection system and method

Life of this patent

Abstract

Claims27