Fluorescence spectrometry optical components

Figure 1.5 Schematics of basic components of analytical techniques based on atomic optical spectrometry, (a) Atomic absorption spectrometry (b) atomic fluorescence spectrometry (c) atomic emission spectrometry.

In both total and sequential dissolutions, the result is a solution containing the components of rocks and soils. This solution is then analyzed by different methods. Mostly, spectroscopic methods are used atomic absorption and emission spectroscopic methods, ultraviolet, atom fluorescence, and x-ray fluorescence spectrometry. Multielement methods (e.g., inductively coupled plasma optical emission spectroscopy) obviously have some advantages. Moreover, elec-troanalytical methods, ion-selective electrodes, and neutron activation analysis can also be applied. Spectroscopic methods can also be combined with mass spectrometry. 

During the last two decades, there has been an enormous increase in the use of photophysical methods in supra-molecular chemistry. Until recently, photophysical methods, such as transient spectrometry and time-resolved fluorescence spectrometry, were primarily research tools in the arenas of photokinetics of small molecules, materials physics, and biophysics. This situation changed dramatically with the introduction of commercial, user-friendly electro-optical components such as charge-coupled detector (ED)-based spectrometers, solid-state pulsed lasers, and other instrumentation necessary for time-resolved measurements. As a result, time-resolved spectrometry became more available to the community of supramolecular chemists, who now reached the level of sophistication that can benefit from the new horizons offered. 

More definitive compound verification may be achieved by (.1) Additional HPLC analyses under altered chromatographic conditions with an accompanying comparison of retention times of standards and unknowns or (2) Collection of component HPLC peaks and subsequent analysis by, for example, mass spectrometry, fluorescence spectroscopy, or optical absorbance spectrophotometry. 

Tt may be safe to say that the interest of environmental scientists in airborne metals closely parallels our ability to measure these components. Before the advent of atomic absorption spectroscopy, the metal content of environmental samples was analyzed predominantly by wet or classical chemical methods and by optical emission spectroscopy in the larger analytical laboratories. Since the introduction of atomic absorption techniques in the late 1950s and the increased application of x-ray fluorescence analysis, airborne metals have been more easily and more accurately characterized at trace levels than previously possible by the older techniques. These analytical methods along with other modem techniques such as spark source mass spectrometry and activation analysis... 

The droplet detection methods described in this entry include fluorescence, surface-enhanced Raman scattering (SERS), electrochemistry, capacitive, and mass spectrometry. The integration of different detection approaches into the microfluidic droplet device typically involves MEMS and optics technologies. Several methods have been employed to address the integration of detection components with the droplet operation unit however, the task of maintaining overall system functionality remains a challenge. As a result, most of these methods are significantly sophisticated. Trends and issues associated with each detection method are presented. 

Determination of the rare-element content in rock samples is a more difficult analytical problem than determination of the main components. The development of optical spectroscopy, X-ray fluorescence analysis, atomic absorption spectrophotometry (AAS), mass spectrometry and other analytical methods from the middle of the 20 century made careful mapping of the composition of the crust possible, even for the rarer elements. The content of each element is given in the corresponding element chapter. 

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