Role of the Spectrophotometer in Medicine

In addition to being an instrumental device for analysis in a wide variety of industries, the spectrophotometer is an indispensable tool throughout the healthcare continuum and is often referred to as the workhorse of the laboratory.

While the spectrophotometer is crucial to industries like paint, cosmetics, food, printing, and many more, its importance within the healthcare continuum cannot be overstated. In many ways, diagnosis, treatment, research and development all revolve around the spectrophotometer.

The spectrophotometer is used for research projects and bioassaysin physics, molecular biology, chemistry, and biochemistry labs among others. Spectrophotometry allows scientists to identify the makeup oforganic and inorganic compounds with the use of both the Ultraviolet light and the visible portions of the light spectrum that can be seen with the human eye (UV-Vis).

Different molecules or inorganic compounds absorb energy at different wavelengths. Those with maximum absorption in the visible range are seen as colored by the human eye. Spectrophotometers use a light source to shine an array of wavelengths through a Monochromator (a means of isolating light of a single wavelength and getting it to the sample compartment).

The spectrophotometer then compares the light intensity passing through the sample to that passing through a reference compound. The readoutshows the degree of absorbance differencebetween them, which indicates the absorbance of the sample compound.

The reason for this absorbance is that both ultraviolet and visible light have enough energy to excite the chemicals to greater energy levels. This excitation results in a higher wavelength, which is visible when the absorbance is plotted against wavelength.

For UV-Vis Spectroscopy, samples are usually contained and measured in small containers called cuvettes. These can be plastic if used in the visible spectrum, but need to be quartz or fused silica if used for UV measurements.

For quantification to be valid, the sample must obey the Beer-Lambert Law, whichdefines the relationship between absorbance and transmittance of light. Lambert’s Law states that the amount of incident light absorbed by a transparent medium is independent of the intensity of the light (barring physical or chemical changes to the medium). Consequently, successive layers of equal thickness will transmit an equal proportion of the incident energy.Beer’s Law states that the absorption of light is directly proportional to both the concentration of the absorbing medium and the thickness of the medium in the light path

There are two types of UV-Vis spectrophotometer machines, single-beam and double-beam. The difference between the two is the way in which they measure the light intensity between the reference and test sample. Double-beam machines measure the reference and test compound simultaneously, while single-beam machines measure before and after the test compound is added.

Spectrophotometers are used in molecular biology laboratories to measure the concentrations of DNA or RNA samples. Microbiology and molecular biology laboratories use spectrophotometers to measure the growth of bacteria cultures.

The device has also proved instrumental in melanoma analysis in pathology laboratories as well.

The study of the natural world, how the human body reacts to it and is changed by it are the building blocks for all medical and clinical procedures and research. Consequently the spectrophotometer is a major cornerstone tool that affects almost every aspect of the healthcare continuum.

Erica is a freelance writer specializing in health technology with a strong interest in laboratory technology such as the Spectrophotometer. Much of the information in this article was researched from the Sensing Konica Minolta website.


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