Küvette

Küvette is the German term for a cuvette, a small, transparent vessel used to hold liquid samples for optical measurements. Cuvettes are essential components in spectrophotometry and related analytical methods, providing a controlled path for light to pass through the sample.

Most cuvettes are made from borosilicate glass or quartz, with plastics such as PMMA, polystyrene, or polycarbonate used for disposable options. Quartz cuvettes are preferred for ultraviolet measurements due to better UV transparency, while glass or plastic cuvettes are common for visible-range analyses. Cuvettes come in various shapes, including square, rectangular, and cylindrical designs, with optical faces that are precisely polished to minimize distortion and stray light.

A key specification is the optical path length, typically 1 centimeter (10 mm) for standard cuvettes, though microcuvettes with shorter path lengths (0.1 to 0.5 cm) are available for small sample volumes. The internal volume depends on geometry and can range from a few hundred microliters to several milliliters. Some cuvettes are designed for UV measurements, others for fluorescence or for use with specific instruments.

Handling and maintenance are important to preserve accuracy. Cuvettes should be handled by the sides rather than the optical faces, and kept free from fingerprints, scratches, and residues. Cleaning methods vary by material: water and mild detergent for glass and quartz; compatible solvents for plastics. Disposable cuvettes are common in routine analyses to avoid cross-contamination.

Etymology traces back to the French cuvette, meaning a small dish or basin; the German term Küvette reflects this origin. In practice, the word denotes any small, optically clean container used for sample measurement in optical instruments.