Cuvettes are not all the same, even if they appear identical. The difference lies in the details and can be crucial for measurement results. Our cuvette windows, for example, which boast outstanding quality and a flatness tolerance of better than 0.001 mm (1 μm). The parallelism of both window surfaces relative to one another is just as important. Our high-precision production guarantees that the frontal deformation of the light wave passing through a cuvette window is less than 4 λ, which works out at approximately 0.001 mm (1 μm) if λ = 546 nm. The high level of flatness demonstrates that the cuvettes from Hellma Analytics are setting standards. Overall, an ideal foundation for conducting reliable, reproducible and exact measurements.

Figure 1: Measurement of the flatness of a Hellma cuvette - the wavefront deformation is extremely low

Figure 2: Measurement of the flatness of a competitor's cuvette - the wavefront deformation is more than twice that of a Hellma cuvette.

Glued cuvettes often cannot meet the requirements of high temperatures and high chemical resistance and fall apart or become leaky when exposed to these conditions. The consequence is a contaminated measuring instrument. For this reason, Hellma only offers thermally bonded cuvettes. For this purpose, the assembled glass components are heated to a temperature well below the melting point of the glass used in an oven. The heating causes an increase in the connection to the joined glass surfaces. Through this process, the final product is monolithic - made of one piece. There are no changes to the optical surfaces and the planarity of the polished surfaces is retained.