The Diamond Probe is a fiber optic ATR accessory designed for analyzing a wide range of samples in the mid-infrared. Sample types include liquids, pastes, slurries, powders, and solids. Samples can be located up to 1.5 meters from the spectrometer. The single reflection 45° diamond ATR element is Harrick’s crowned hemisphere, mechanically sealed in 316 stainless steel. The Probe has a diameter of 19 mm and an immersion depth of 125 mm. It is separately purgeable. An MCT detector-equipped FTIR spectrometer is required. The Probe is especially useful in monitoring liquid reactions. Temperatures up to 140 °C and pressures up to 0.55 MPa can be tolerated. Applications include fermentation, crystallization, and polymerization. The Diamond Probe requires that a fiber optic coupler, such as the Harrick FiberMate2™, be installed in the spectrometer. Also, the Probe and FiberMate2™ must be optically connected via two SMA terminated fiber optic cables such as those offered by Harrick.