UV/VIS absorbance measurements cover a range of chemical and biochemical applications which involve various areas of industrial and research applications.
In spectroscopic measurement applications, UV/VIS absorbance can be applied both quantitatively and qualitatively. These applications range from chemical concentrations in process and reaction monitoring to blood parameters.
Fiber-optic spectrometers are very useful for UV/VIS measurements owing to their small size and low price factors. These instruments can also be introduced in rough environments via the fiber interface.
A fiber-optic spectrometer, coupled with inline flow cells, fiber-optic transmission dip probe or cuvette cell, can precisely and repeatably measure over the 200-1100nm range.
Researchers who use conventional bench top spectrophotometers may believe that fiber-optic instruments are not capable of providing the resolution or stray-light rejection needed for more complex applications.
However, fiber-optic spectrometer technology has undergone significant improvements over the years and Avantes’ instruments are on the forefront for this technology. The instruments can measure at resolutions as high as 0.05nm in the UV range.
With respect to stray-light rejection, Avantes has designed a unique optical bench, known as the ultra-low stray-light (ULS) optical bench, to provide superior performance. Furthermore, AvaSpec ULS spectrometers have stray-light levels down to 0.04%.
Generally, UV/VIS absorbance systems includes a spectrometer, fiber- optics, and stabilized light source, which are joined to a sampling accessory such as a cuvette cell or probe.
Depending upon the required resolution and wavelength range, single fiber-optic spectrometers can be configured for narrow band or broadband measurements. Avantes UV/VIS instruments can also be used with AvaSpec NIRLine spectrometers, which facilitate spectroscopic measurements out to 2500nm range.
Configuration of Common Systems
Using Avantes modular platform, users can easily configure their systems in a number of ways and can also modify the system configuration later on to get additional functionality. The standard UV/VIS absorbance system includes an AvaSpec spectrometer, fiber cables, an AvaLight fiber-optic light source, and a cuvette cell holder. Figure 1 shows the system configuration with a cuvette cell holder above with a dip probe configuration below.
Figure 1. System configuration with a cuvette cell holder and a dip probe
The AvaSpec-ULS2048-USB2 and AvaSpec-ULS3648L-USB2 are low-cost instruments that provide higher resolution for a shorter-range configuration or excellent resolution over the entire 200-1100nm range.
To this end, the AvaSpec-ULS3648-USB2 is recommended for higher resolution. Avantes SensLine instruments are recommended for customers requiring higher sensitivity and higher signal-to-noise performance in the NIR or UV range.
The AvaSpec-ULS2048XL features a high-performance back-thinned CCD detector. Avantes also offers a high-sensitivity spectrometer called AvaSpec-HS1024X58/122-TEC, which features a high numerical aperture optical bench and a thermo-electrically cooled CCD detector.
All Avantes instruments are compatible with the AvaLight-DHS-BAL deuterium halogen source and a CUV-UV/VIS cuvette cell holder. The CUV-DA-DHS serves as an excellent substitute and can be used for joining the cuvette cell holder to the front plate of the light source so as to reduce the use of fiber-optics.
The same system configuration can be incorporated into a single enclosure to provide an integrated spectrophotometer module equipped with a common power supply for the spectrometer and light source.
Fiber-optic Transmission Dip Probes
A major aspect of fiber-optic instruments is the ease with which measurements can be performed in-process or inline utilizing a fiber-optic probe or accessory.
Avantes offers a wide range of configurations and sizes of fiber-optic transmission dip probes, which comprise unique configurations for measurements in high pressure, high temperatures, or vacuum. Fiber-optic flow cells are also available for both standard and micro-fluidic applications.
Software for Instrument Control
Avantes offers a Windows-based 32- and 64-bit compatible software package called AvaSoft software. This software allows complete instrument control and comprises a basic chemometry add-on module.
Avantes instruments can also be used with Panorama-Pro software from LabCognition. This proves useful for customers requiring more advanced analytical software for multi-variate analysis and model development.
Avantes’ instruments are suitable for UV/Vis/NIR absorbance measurements, and fiber-optic spectrometers are particularly useful for these applications as they are compact, low cost, and can be used in harsh environments.
This information has been sourced, reviewed and adapted from materials provided by Avantes BV.
For more information on this source, please visit Avantes BV.