Cold trapping apparatus for infrared transmission analysis including a method and substrate therefor

A holder for holding a sample in a sample matrix, which comprises:

• a) a substantially pure semiconductor wafer having a thickness between about 0.5 mm and 2.0 mm and having a surface area of sufficient dimension to permit the wafer to hold the sample in a sample matrix;
• b) an indexed support means for movably supporting the semiconductor wafer;
• and
• c) heat transfer means, in thermal communication with the semiconductor wafer, for cooling the wafer to a sufficiently low temperature to solidify the sample, wherein the heat transfer means includes a flexible strap connected in thermal communication with the wafer, wherein the strap is made of a thermally conductive material.

A process for analyzing a sample held in a sample matrix, comprising the steps of:

• a) cooling a semiconductor substrate via a flexible strap connected in thermal communication with the substrate;
• b) depositing the sample onto a surface of the substrate to form a sample matrix;
• c) transmitting a beam of electromagnetic radiation through the sample matrix and substrate;
• d) collecting the portion of electromagnetic radiation transmitted through the sample matrix and substrate;
• and
• analyzing the collected portion of electromagnetic radiation to determine spectral features of the sample.

A device for holding a sample matrix, which comprises:

• a) an enclosure having walls which define a vacuum chamber, including a means for evacuating gas from the chamber;
• b) a semiconductor substrate wafer disposed within said vacuum chamber, the substrate wafer having a longitudinal axis and having a transmissive surface region which transmits infrared and wherein the substrate wafer is rotatably supported about said longitudinal axis;
• c) inlet means for depositing and solidifying a sample onto said transmissive surface region of the substrate wafer;
• and
• d) heat transfer means, in conductive communication with the wafer, for maintaining said transmissive surface region at a sufficiently low temperature to solidify the sample thereon, wherein the heat transfer means includes a flexible strap connected in thermal communication with the transmissive substrate, wherein the strap is made of a thermally conductive material.

A device for holding a sample matrix, which comprises:

• a) an enclosure having walls which define a vacuum chamber, including a means for evacuating gas from the chamber;
• b) a semiconductor substrate wafer disposed within said vacuum chamber, the substrate wafer having a longitudinal axis and having a transmissive surface region which transmits infrared, wherein the substrate wafer is rotatably supported about said longitudinal axis and wherein the substrate wafer is made of substantially pure germanium;
• c) inlet means for depositing and solidifying a sample onto said transmissive surface region of the substrate wafer;
• and
• d) heat transfer means, in conductive communication with the wafer, for maintaining said transmissive surface region at a sufficiently low temperature to solidify the sample thereon, wherein the heat transfer means includes a flexible strap connected in thermal communication with the transmissive substrate, wherein the strap is made of a thermally conductive material.

A device for holding a sample matrix, which comprises:

• a) an enclosure having walls which define a vacuum chamber, including a means for evacuating gas from the chamber;
• b) a semiconductor substrate wafer disposed within said vacuum chamber, the substrate wafer having a longitudinal axis and having a transmissive surface region which transmits infrared, wherein the substrate wafer is rotatably supported about said longitudinal axis and wherein the substrate wafer is made of substantially pure gallium arsenide;
• c) inlet means for depositing and solidifying a sample onto said transmissive surface region of the substrate wafer;
• and
• d) heat transfer means, in conductive communication with the wafer, for maintaining said transmissive surface region at a sufficiently low temperature to solidify the sample thereon, wherein the heat transfer means includes a flexible strap connected in thermal communication with the transmissive substrate, wherein the strap is made of a thermally conductive material.

A device for holding a sample matrix, which comprises:

• a) an enclosure having walls which define a vacuum chamber, including a means for evacuating gas from the chamber;
• b) a semiconductor substrate wafer disposed within said vacuum chamber, the substrate wafer having a longitudinal axis and having a transmissive surface region which transmits infrared and wherein the substrate wafer is rotatably supported about said longitudinal axis, wherein heat transfer means are provided in conductive communication with the substrate wafer to maintain said transmissive surface region at a sufficiently low temperature to solidify the sample matrix onto said transmissive surface region and wherein:
• a) the rotatably supported substrate wafer includes an axle made from a thermally conductive material;
• b) the drive means includes means for thermally insulating the drive means from the axle;
• and
• c) the heat transfer means includes a thermally conductive flexible strap connected at a first end to the axle and connected at a second end to a cryogenic cooling means, the strap having sufficient length and flexibility to allow the substrate wafer to rotate through an angle of about 360 degrees;
• and
• c) inlet means for depositing and solidifying a sample onto said transmissive surface region of the substrate wafer.

A system for cold trapping a sample for chromatographic analysis, which comprises:

• a) a device for holding the sample, which includes:
• i) an enclosure having walls which define a vacuum chamber, including a means for evacuating gas from the chamber;
• ii) a semiconductor substrate wafer disposed within said vacuum chamber, the substrate wafer having a longitudinal axis and having a transmissive surface region which transmits infrared radiation, wherein the substrate is rotatably supported about said longitudinal axis,
• iii) inlet means for depositing and solidifying the sample onto said transmissive surface region of the substrate, and
• iv) heat transfer means, in conductive communication with the substrate wafer, for maintaining said transmissive surface region at a sufficiently low temperature to solidify the sample onto said transmissive surface region, wherein the heat transfer means includes a flexible strap connected in thermal communication with the transmissive substrate, and wherein the strap is made of thermally conductive material;
• and
• b) a gas chromatograph, wherein the inlet means of the device for holding the sample is interconnected with the gas discharge of the chromatograph to provide clusters of gas samples for deposition onto respective areas of the transmissive surface region.

A system for cold trapping a sample for chromatographic analysis, which comprises:

• a) a device for holding the sample, which includes:
• i) an enclosure having walls which define a vacuum chamber, including a means for evacuating gas from the chamber;
• ii) a semiconductor substrate wafer disposed within said vacuum chamber, the substrate having a longitudinal axis and having a transmissive surface region which transmits infrared radiation, wherein the substrate is rotatably supported about said longitudinal axis,
• iii) inlet means for depositing and solidifying a sample onto said transmissive surface region of the substrate, and
• iv) heat transfer means, in conductive communication with the substrate wafer, for maintaining said transmissive surface region at a sufficiently low temperature to solidify the sample onto said transmissive surface region, wherein the heat transfer means includes a flexible strap connected in thermal communication with the transmissive substrate, and wherein the strap is made of thermally conductive material;
• and
• b) a supercritical fluid chromatograph, wherein the inlet means of the device for holding the sample is interconnected with the fluid discharge of the chromatograph to provide clusters of fluid samples for deposition onto respective areas of the transmissive surface region.

A system for cold trapping a sample for chromatographic analysis, which comprises:

• a) a device for holding the sample, which includes:
• i) an enclosure having walls which define a vacuum chamber, including a means for evacuating gas from the chamber,
• ii) a semiconductor substrate wafer disposed within said vacuum chamber, the substrate having a longitudinal axis and having a transmissive surface region which transmits infrared radiation, wherein the substrate is rotatably supported about said longitudinal axis,
• iii) inlet means for depositing and solidifying the sample onto said transmissive surface region of the substrate, and
• iv) heat transfer means, in conductive communication with the substrate wafer, for maintaining said transmissive surface region at a sufficiently low temperature to solidify the sample onto said transmissive surface region, wherein the heat transfer means includes a flexible strap connected in thermal communication with the transmissive substrate, and wherein the strap is made of thermally conductive material;
• and
• b) a liquid chromatograph, wherein the inlet means of the device for holding the sample is interconnected with the fluid discharge of the chromatograph to provide clusters of fluid samples for deposition onto respective areas of the transmissive surface region.

Apparatus for transmission analysis of a chemical sample comprising:

• a) an enclosure having walls which define a vacuum chamber, including means for evacuating gas from the chamber;
• b) a substrate that is disposed within the chamber and that is transmissive to a desired region of the electromagnetic spectrum;
• c) a frame which holds the substrate and which defines a transmissive surface region thereon;
• d) inlet means for depositing and solidifying a sample onto the transmissive surface region;
• and
• e) means for moving the frame to produce a trace of the solidified sample upon the transmissive surface region of the substrate;
• f) heat transfer means, in conductive communication with the substrate, for maintaining the transmissive surface region at a sufficiently low temperature to solidify the sample thereon, wherein the heat transfer means includes a flexible strap connected in thermal communication with the transmissive substrate, wherein the strap is made of thermally conductive material.

A holder for holding a sample in a sample matrix, which comprises:

• a) a transmissive substrate that is transmissive to a desired region of the electromagnetic spectrum;
• b) an indexed support means for movably supporting the transmissive substrate;
• and
• c) heat transfer means, in thermal communication with the transmissive substrate, for cooling the substrate to a sufficiently low temperature to solidify the sample, wherein the heat transfer means includes a flexible strap connected in thermal communication with the substrate, wherein the strap is made of a thermally conductive material.