subject: How Spectrophotometers Offer Flexibility In The Laboratory [print this page] Spectrophotometry quantifiably measures the range of all possible frequencies of electromagnetic radiation. The spectrophotometer is extremely helpful as it measures the intensity of a wavelength (color of light), a measurement used regularly in physics, biology and biochemistry. The spectrophotometer is generally used to quantify light absorption but can also be used to measure diffuse or specular reflectance. The most common and basic spectrophotometers only measure visible and UV ray, but specifically designed machines measure infrared, gamma and X-rays.
The single beam spectrophotometer measures relative light intensity before and after a sample is used, while a double beam spectrophotometer dually compares a reference sample to a testable unknown sample. The convenience of a double beam unit is not always beneficial in terms of results, as the single beam will generally yield more accurate and detailed readings. The utilization of a monochromator allows you to set a wavelength for measurement.
Within the monochromator is the presence of a diffraction grating that splits the lights into different directions (in a form of a rainbow). This light is then sent through the unknown sample allowing a quantifiable observation to be made. Some spectrophotometers use a Fourier transform method that acquires the spectral reading much faster.
Ultraviolet-visible spectrometry utilizes visible light between 400-700 nanometers and has two separate mechanisms based on the architecture of the light sourceas well as the observer and interior of the measurement chamber. In the lab this setup is applied to measure components in a compound or solution. Spectroradiometers can then convert the light of transmission or reflection to yield a number. If the concentration of the components is high, more light will be absorbed, if it is low, less light will be absorbed. Thus, absorbency is proportional to concentration in a linear fashion.
Infrared spectrophotometry is much more technical both in measurement and in setup. Photosensors must be chosen in accordance to differentiating spectrums - and sometimes they are not always available. Also, infrared light is always translated into thermal radiation (the emission of heat) making it difficult to quantify. Optical challenges such as materials that end up absorbing the infrared (such as glass and plastic) only further the difficulty of applying the spectrophotometer.
Scientifically, the spectrophotometer can identify and measure complex molecules in a solution. They are even able to detect early signs of diseases such as cancer. This device, however, is not just confined to the laboratory. Many industries have uses for it, such as the ink manufacturers, printing companies and textile vendors who use spectrophotometric readings to develop their products.
In general, this tool has been an extremely helpful development to both scientists as well as manufacturers. The design is quite basic despite that complexity of its parts, but the uses are many.
