A spectrophotometer is perfectly adapted to measure how much a chemical of interest absorbs or transmits a given wavelength of light, thus producing information on concentration and purity. A cuvette is inserted in the spectrophotometer's standard-sized chamber, allowing a specific wavelength of light to travel a specific distance through the sample, which is referred to as the path length. The sample type, volume requirements, concentration levels and measurements being done should affect your decision when selecting the proper cuvette for your samples and applications.

Consider the following options while selecting a cuvette:

 A macro cuvette requires a volume of measurement more than 1.5 to 2 ml.
 The normal measurement volume for a conventional cuvette is between 50 ml and 2 ml.
 A microvolume adapter calls for samples within a single microliter range, often between 2 ml and 10 ml.

In addition, it is essential to ensure that the cuvette used is transparent to the wavelengths that will be utilized to measure the samples of interest. Glass and polystyrene normally transmit visible light but absorb ultraviolet light. Glass and polystyrene are therefore ideal for colorimetric protein assays and detecting the density of a bacterial culture, but not for determining the concentration and purity of nucleic acids in the UV range at 230, 260, and 280 nm. Quartz and other UV-compatible polymers, on the other hand, are often transparent in both the visible and UV light spectrums, making them suitable for measuring samples in the UV-light spectrum.

Both the cuvette and the microvolume adapter has advantages and limitations. Here are some guidelines for selecting the suitable vessel for measuring your samples accurately and reliably.

Microvolume adapters

A microvolume adapter is a cuvette-shaped measurement cell that is designed to fit into a cuvette chamber, and it requires a minimal sample volume ranging from 1 ul to 10 ul, depending on the adapter. The sample is held between two optically clear quartz plates at a brief, constant distance. The set distance in the Eppendorf Cuvette G1.0 is 1.0 mm, allowing for a minimal path length across the sample. Microvolume adapters are also reusable, requiring only a wipe with a lint-free tissue before reading the next sample, in addition to the apparent benefit of requiring less amounts of sometimes valuable material. Consider the following additional microvolume adapter features:

It is easier and quicker to measure a tiny volume over a short path length than to dilute a sample in numerous steps. Additionally, since there are fewer pipetting processes, the readings are more likely to be correct.

The path length of microvolume adapters is shorter than that of a cuvette. When testing highly concentrated nucleic acids and/or proteins, readings with a microvolume adapter are more trustworthy and accurate than when analyzing more diluted sample preparations.

The reusability of microvolume adapters eliminates the need to regularly renew your supply of disposable cuvettes. It is possible to recover valuable undiluted samples for certain downstream applications, such as those that do not require sterility.

A typical spectrophotometer is capable of accommodating a variety of cuvettes and even a microvolume adaptor. The selection of the right cuvette or microvolume adapter is impacted by the sample type, volume used, path length, and transparency of the cuvette material, allowing scientists to conduct experiments reliably and precisely. Review the previously discussed settings, then set the wavelength and path length and begin measuring!