Infra-red analysis apparatus and method
AssigneeCoal Industry (Patents) Limited
InventorJohn McCue
Life of this patent
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Abstract
The technique of attenuated total reflection (ATR) analysis can be applied to the deposit on a filter, enabling crystalline silica deposited on a glass fibre filter to be determined, which is impossible using transmission IR spectrophotometry. An improved ATR apparatus has pressure means to bring a sample such as that collected on a filter into contact with the prism and is arranged such that the face of the prism defines the area of the sample for analysis.
Claims7
An IR attenuated total reflection apparatus capable of reproducible quantitative analysis of crystalline silica in air-borne dust, said apparatus comprising a planar crystal ATR prism having a smaller major face and a larger major face and edges, one pair of edges being bevelled and capable of acting as entry and exit faces for an IR beam, a prism support, a beam reflection system for transmitting an IR beam into and from the edges of said prism, and pressure means for bringing a planar sample into contact with the larger major face of the prism and for applying a constant reproducible predetermined pressure thereto, the contact of said larger major face of the prism with the sample defining a constant reproducible sample area for analysis.
A method of quantitatively analyzing a material deposited on a filter which comprises the steps of providing a crystal ATR prism having a smaller major face and a larger major face, contacting the larger major face of said ATR prism with at least a portion of a deposit-laden face of a filter to define a constant reproducible area for analysis, said contact being at a constant reproducible predetermined pressure, passing an IR beam through said prism and analyzing the infra-red spectrum of the deposit by attenuated total reflection of the IR beam passing through said prism.
Dependencies are inferred from the claim text.