The characteristic movement of electrons when exposed to particular types or wavelengths of energy produces signature energy fingerprints called spectra. The energy movement of electrons in orbitals use or produce measurable changes in energy usually as photons ( Figure 3). In atomic spectroscopy, changes in energy are most commonly measured by the movement of electrons in atomic orbitals when exposed to an energy source such as light. Some techniques focus on a narrow band of interactions (such as emission only) or a small part of the EM spectrum (like X-rays) while other techniques monitor an array of interactions and wavelengths on the spectrum (see Table I). Spectroscopy techniques are divided into atomic and molecular spectroscopy depending on the target to be measured and the material being evaluated.Spectrometry instruments are often further divided and defined by the type of interactions they produce and the type of energy that is measured like X-ray fluorescence (XRF), which measures X-rays and the amount of fluorescent energy a material emits during exposure. All of these processes become the basis for some form of detection or spectroscopy measurement technique (see Figure 2).Ītomic Spectroscopy Properties and Methods These include some of the most commonly used interactions in instrumentation including absorption, transmission or refraction, reflection, and emission. There are numerous interactions between EM and matter. Many laboratory analytical techniques are focused on the range of waves associated with light from infrared to the X-ray range of wavelengths. The designation of the type of spectroscopy is categorized by the area of the electromagnetic spectrum targeted (for example, infrared, ultraviolet, or X-ray, and so forth), the atomization source and interaction (such as emission, adsorption, transmittance, and so on), or the type of spectroscopy being employed (optical or mass spectrometry).Įlectromagnetic (EM) radiation spectrum encompasses a wide band of energy including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays (see Figure 1). In organic analysis, spectroscopy examines the interaction of energy and molecules, but in inorganic chemistry we focus on atomic spectroscopy or the interaction of atoms and energy. Spectroscopy is the study or measurement of the interaction of matter and electromagnet radiation resulting in spectra (wavelength or frequency of the radiation). In the previous columns we have examined spectroscopy as a tool of organic chemical analysis. In the next few columns, we will look at another critical aspect of analytical chemistry-atomic spectroscopy and elemental analysis. Up until this point, we have been mainly focused on the techniques commonly used in molecular spectroscopy and chromatography, which all have organic molecules as their target analytes. The knowledge of the theories behind the scenes can be used to manipulate the method variables for a more accurate and precise result. In this column, we attempt to explore in depth the theory and methodology of our common laboratory techniques and show how an understanding of interworking of those techniques allow for more flexibility in analysis.
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