Abstract: A liquid cell for IRS comprising a rod-shaped crystal having a cylindrical sampling surface and integral conical end portions forming end entrance and exit faces for a radiation beam. The center of the end faces are masked. All radiation entering the entrance face internally reflects from the conical surface and propagates down the IRE by multiple internal reflections from the cylindrical sampling surface. The IRE can be sealed into a trough or flow-through housing for the liquid sample. The seals are at insensitive regions of the IRE.

Abstract: An ultra-small sample analyzer for internal reflection spectrometry comprises a small hemispherical crystal of an infrared-transparent hard material whose flat surface receives the sample to be analyzed. The analyzing beam is contracted to a very small size when incident on the hemispherical surface. Pressure-applying means of a size substantially matching that of the beam at the sampling surface enables interaction of substantially the entire beam with the sample producing spectra of high contrast from microgram or nanogram quantities of the sample.

Abstract: Optical spectroscopy in a purging atmosphere wherein an optical accessory is gas-tight coupled in the spectrometer sample compartment to the open beam port of the spectrometer, whereby the same purging gas used by the spectrometer can be employed to purge the accessory. Where the accessory allows external sample placement or external adjustments, rapid sample changing or adjustment is possible without breaking the purge seal. In another embodiment, the accessory has its own purge inlet and sealed windows for receiving the spectrometer beam.