Spectrometry is the measurement of the interactions between light and matter, and the reactions and measurements of radiation intensity and wavelength. Mass spectrometry is an example of a type of spectrometry, and it measures masses within a chemical sample through their mass-to-charge ratio. This is usually done by ionising particles with a shower of electrons, then passing them through a magnetic field to separate them into different stages of deflection.
Typically, scanning electron microscopes offer options for spectrometry based on the application. The practical uses of mass spectronomy include isotope dating and protein characterisation. Independent roving space exploration robots such as the Mars Phoenix Lander also carry mass spectrometers for the analysis of foreign soils. The study of spectrometry dates back to the s when Isaac Newton first discovered that focusing light through glass split it into the different colours of the rainbow known as the spectrum of visible light.
The spectrum itself is an obviously visible phenomenon it makes up the colours of the rainbow and creates the sheen you see on the surface of a puddle , but it took centuries of piecemeal research to develop the study of this phenomenon into a coherent field that could be used to draw usable conclusions.
Generations of work by scientists, such as William Hyde Wollaston, lead to the discovery of dark lines that were seemingly randomly placed along this spectrum. Simply put, as natural light filters from celestial bodies in space such as the sun, it goes through various reactions in our atmosphere. Each chemical element reacts slightly differently in this process, some visibly those on the mm wavelength that are detectable to the human eye and some invisibly like infrared or ultraviolet waves, which are outside the visible spectrum.
Something they learned about an interest of theirs? I provide an example of how I used UV light to purify water sources water from creeks, lakes, stagnant ponds in Oregon, etc. See the video below for this UV-purification process in action. UV lamps used to disinfect surgical operating rooms.
Using MRI spectroscopy to detect tumors. A phone app that uses light reflection to help determine if a toddler has an eye tumor. Anyone interested in Art Forgery. Using bloodstains at crime scenes to determine age of a suspect or victim. Quantum Engineering - What is it? Leon Foucault, a French physicist, observed in that a flame containing sodium would absorb the yellow light emitted by a strong arc placed behind it.
This was the first demonstration of a laboratory absorption spectrum. All of these facts were brought together in by Gustav Kirchhoff in his famous law, which states that the emitted power and absorbed power of light at a given wavelength are the same for all bodies at the same temperature.
It follows that a gas, which radiates a line spectrum must, at the same temperature, absorb the spectral lines it radiates. From this, Kirchhoff and R. Bunsen explained that the Fraunhofer lines in the sun's spectrum were due to absorption of the continuous spectrum emitted from the hot interior of the sun by elements at the cooler surface. By recognising that each atom and molecule has its own characteristic spectrum, Kirchhoff and Bunsen established spectroscopy as a scientific tool for probing atomic and molecular structure, and founded the field of spectrochemical analysis for analysing the composition of materials.
This is known as a spectrum. The electromagnetic spectrum extends from below the low frequencies used for modern radio communication to gamma radiation at the short-wavelength high-frequency end, thereby covering wavelengths from thousands of kilometers down to a fraction of the size of an atom.
Visible light lies toward the shorter end, with wavelengths from to nanometres. Nearly all types of electromagnetic radiation can be used for spectroscopy to study and characterise matter. When using X-rays the photoelectric effect occurs.
The photoelectric effect refers to the emission, or ejection, of electrons from the surface of a sample in response to electromagnetic radiation, or light. Energy contained within the electromagnetic radiation is absorbed by electrons within the sample, giving the electrons sufficient energy to be 'knocked' out of, that is, emitted from, the sample.
In the X-ray region atoms absorb X-rays sharply at certain wavelengths called absorption edges that are characteristic of that particular atomic species. So if you shine a particular frequency, or energy, of X-rays onto a sample, you can control the type of electron that is emitted. If sufficient energy is provided, the electron is ejected from the atom forming a photoelectron which affects neighbouring atoms;.
The atom is left in excited state with an empty electronic level i. An absorption graph is produced which provides researchers with element-specific information from the sample. This can include which elements are present, where they are located, the density of the element, what are the neighbouring atoms and the distance between those atoms.
X-ray absorption spectroscopy XAS is an element-specific technique dedicated to study electronic and structural properties of selected element.
This unique technique is greatly appreciated when studying non-crystalline materials. At characteristic wavelengths the X-ray absorption of an element changes dramatically, these are called absorption edges.
XAS is a technique that can be divided into XANES - near the absorption edge, the spectra may contain fine structure that reveals the electronic and geometrical environment of the absorbing atom - and further from the edge EXAFS reveals the atomic environment local to the element. Both can be used to follow reactions on timescales down to the millisecond. X-ray absorption spectroscopy is important in gaining structural understanding of a range of materials, including catalysts, biomaterials, novel materials with special electronic properties such as superconductivity, dilute species in fluids, and complex inhomogeneous materials.
Manufacturers have to be careful how it changes in meat, for example, since the wrong pH can create undesirable products or properties. Most quality-testing solutions for usually require the destruction of some of the product for lab tests. And that testing can be a lengthy process. If the testing is on-site, the results may take a few hours.
Off-site testing could take several days. Chromatography and atomic absorption spectroscopy have historically been the common analytical techniques in the agriculture industry for a wide variety of analyses. Unfortunately, each method takes significant sample preparation and long delays to get the results. Fluorescence spectroscopy offers a faster and cheaper opportunity for this analysis.
Olive oil includes phenolic compounds , which scientists believe, can contribute to a lower rate of coronary heart disease, and prostate and colon cancers. Phenolic compounds also affect sensory attributes and the oxidative stability of olive oils.
Various bioactivities of phenolic compounds are responsible for their chemopreventive properties, like antioxidant, anticarcinogenic, or antimutagenic and anti-inflammatory effects. Researchers can use fluorescence spectroscopy, near-infrared spectroscopy and mid-infrared spectroscopy to measure those phenolic compounds and determine the makeup of olive oil. But fluorescence spectroscopy, they found, can do it faster. Refined oils lack the antioxidants and anti-inflammatories that gives unrefined extra-virgin olive oil its phenolic benefits.
Researchers have found that olive oils have unique fluorescent fingerprints. Photodynamic therapy, which targets a specific group of tissues, is a treatment that is used primarily to treat cancers that are near an accessible surface of the body.
You need three things for photodynamic therapy - light, a photodynamic molecule or metal compound as the mediator, and the oxygen in the microenvironment. The product of this reaction, a reactive singlet oxygen species, kills the cancer. Spectroscopy plays an important role in identifying the most productive photodynamic molecules to activate the process. In photodynamic therapy, a cancer patient has a fiber optic light either inserted into, or placed just outside their body.
This light emits visible wavelengths. It reacts with photosensitizer photodynamic molecules and provides energy to oxygen in the microenvironment. That, in turn, generates non-toxic singlet oxygen species, which shrink or kill the tumor. Erosion and creeping shores threaten landmasses.
Many scientists believe that global warming may be behind rising sea levels and flooding, which in turn destroys the coastlines. Yet when we harvest drinking water from aquifers over periods of years, land levels decrease, accelerating the pace of seawater intrusion. One east coast group has found a way to replenish a depleted aquifer with wastewater after undergoing advanced treatment processes.
Raman spectroscopy is a non-destructive chemical analysis technique which provides detailed information about chemical structure, phase and polymorphy, crystallinity and molecular interactions. The basis of Raman spectroscopy is the interaction of light with the chemical bonds within a material. Raman is a light scattering technique, whereby a molecule scatters incident light from a high intensity laser light source.
Most of the scattered light is at the same wavelength as the laser source and does not provide useful information — called Rayleigh Scatter.
However, a small amount of light is scattered at different wavelengths, which depend on the chemical structure of the sample — we call this Raman Scatter. Researchers commonly use the technique to create a structural fingerprint of a sample, identifying it through its Raman characteristics. Raman bands arise from a change in the polarizability of the molecule due to an interaction of light with the molecule.
When scientists plot these transitions as a spectrum, they can be used to identify the molecule observed. Researchers use Raman spectroscopy in chemistry to identify molecules and study chemical bonding and intramolecular bonds. Paleobiology is the study of ancient life. One way to do that is to look at slivers of rocks for evidence of the earliest life on earth.
Most likely, those discoveries will come from the similarity of specimens we find here on earth and deep beneath extraterrestrial bodies. Researchers are looking for fossils of microorganisms in rock, or at least their chemical signatures. The carbon molecules are one indicator of life.
Scientists use Raman spectroscopy to identify the fossil. They do it using thin strips of rocks they shave off from larger pieces, so thin it becomes transparent. Raman spectroscopy gives researchers a spectrum of whatever material it is. Researchers use Raman spectroscopy to characterize microscopic pieces of plastic that invade our environment.
These materials, those both engineered and those that are the product of decomposition, might pose health hazards.
Scientists use Raman spectroscopy to trace the trail of microplastics that are becoming a greater threat to our surroundings. Body fluid traces are important because they are the main source of DNA evidence. Currently, police use various biochemical tests to detect and identify body fluids.
But those tests are destructive — they alter the sample. The tests are also presumptive, and generate many false positives.
Researchers are using Raman technology as the first method to develop a universal, confirmatory test of body fluids. Gunshot reside can also be examined using Raman spectroscopy to identify the caliber of the weapon used in a discharge.
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