A small transparent tube or container with
specific optical properties. The chemical composition of the container
determines the vessel's use, such as Pyrex glass for examining materials in the
visible spectrum or silica for those in the ultraviolet range. It is used in
laboratory research and analyses, such as photometric evaluations, colorimetric
determinations, and turbidity studies.
A cuvette is a small tube of circular or
square cross section, sealed at one end, made of plastic, glass, or fused
quartz (for UV light) and designed to hold samples for spectroscopic
experiments. The best cuvettes are as clear as possible, without impurities
that might affect a spectroscopic reading. Like a test tube, a cuvette may be
open to the atmosphere on top or have a cap to seal it shut. Parafilm can
also be used to seal it.
Inexpensive cuvettes are round and look similar
to test tubes. Disposable plastic cuvettes are often used in fast spectroscopic
assays, where speed is more important than high accuracy.
Some cuvettes will be clear only on opposite
sides, so that they pass a single beam of light through that pair of sides;
often the unclear sides have ridges or are rough to allow easy handling.
Cuvettes to be used in fluorescence spectroscopy[ must be clear on
all four sides because fluorescence is measured at a right-angle to the beam
path to limit contributions from beam itself. Some cuvettes, known as tandem
cuvettes, have a glass barrier that extends 2/3 up inside, so that measurements
can be taken with two solutions separated, and again when they are mixed.
Typically, cuvettes are 10 mm (0.39 in) across, to allow for easy
calculations of coefficients of absorption.
Cuvettes to be used in circular dichroism experiments
should never be mechanically stressed, as the stress will induce birefringence[
in the quartz and affect the measurements made.
Types
of cuvettes
There are three different types of
cuvettes commonly used, with different usable wavelengths:
- Glass, with a wavelength from 380 to 780 nm (visible spectrum).
- Plastic, with a wavelength from 380 to 780 nm (visible spectrum).
- Fused quartz, with a wavelength below 380 nm (ultraviolet spectrum).
- UV quartz has a usable wavelength of around 185 nm, and a matching tolerance of 1% at 220 nm.
- ES quartz has a usable wavelength range of 190 to 2,000 nm, and a matching tolerance of 1% at 200 nm.
- IR quartz has a usable wavelength range of 220 to 3,500 nm, and a matching tolerance of 1% at 2,730 nm.
1. | What is the maximum operating temperature for the UV-Cuvettes? | |
The UV-Cuvettes can be used at temperatures up to 60 degrees Celsius for several hours. | ||
2. | I have selected the correct size UV-Cuvettes for my spectrophotometer, but still am not getting appropriate results. Why? | |
If
you are using the appropriate window height (z-dimension) ultra-micro
UV-Cuvette for your spectrophotometer, and are not getting appropriate
results, it is likely due to one of two different problems.
| ||
3. | What is the difference between your PS, PMMA and UV-Cuvettes | |
Polystyrene (PS) cuvettes are the least expensive, however they have the lowest chemical resistance, and are only suitable for visible light applications, with a lower wavelength limit of around 340nm. Polymethyl methacrylate (PMMA or “acrylic”) cuvettes extend that range to about 300nm, or slightly into the near UV range, and have slightly greater chemical compatibility. BRAND UV-Cuvettes use a proprietary plastic to allow measurement as low as 220nm, and has resistance to many polar organics as well as many acids and bases. | ||
4. | What does “mold cavity matched” mean? | |
Cuvettes are injection molded plastic. No matter how close the tolerances are in the molds, there will be some variance. BRAND cuvettes are sorted during the manufacturing process so that each package of cuvettes contains only cuvettes made from the same mold, minimizing the cuvette-to-cuvette variance. | ||
5. | Do you sell four-clear-side flourimetry cuvettes? | |
No. | ||
6. | My results with your UV-Cuvettes are different than with quartz. What’s happening? | |
While our UV-Cuvettes allow enough light to pass to perform accurate spectrophotometry down to 220nm, they are not as transparent as quartz. When using UV-Cuvettes, any reference measurements should also be done with UV-Cuvettes. |
Cuvettes are made of different materials , there are different types of cuvettes available. glass & plastic cuvettes are very popular and information you shared about cuvettes is good.
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