Remote Analysis

Remote (standoff) LIBS systems have been built by Applied Photonics Ltd. with a range capability of 100 m for defense departments. They also built a transportable standoff LIBS with a 20 m range to characterize radioactive materials in a hot cell at the Sellafield, UK, high-level nuclear waste vitrification plant by directing the laser beam through the lead-glass window of the cell. LIBS is an excellent tool for remote and in situ detection of uranium oxide fuel located in hard-to-reach 

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Remote analysis is provided by specific software developed at Laborelec. This enables us to configure the software to the needs of our analysis. 

Optical fibers which were developed primarily for the communication industry have been successfully implemented into other disciplines such as chemistry, physics, and biomedicine. Mass production of high-quality fibers by a variety of manufacturers has rendered themrelatively inexpensive. The use of optical fibers is rapidly increasing because of their size, cost, and easy mode ofoperation.(62) Table 7.1 shows properties of some commercially available optical fibers. Originally, optical fibers were made of glass but more recently they have become available as organic polymers or metal halides. They are flexible, stable, and resistant to many chemicals. Furthermore, optical fibers can improve safety by allowing the remote analysis of potentially harmful chemicals. A detailed review of the development of optical fibers has been previously published/63 ... 

A plethora of methods has been developed to evaluate renal function by dynamic renography and remote analysis of the excretion of renal function markers. The underlying principle is that the kidneys excrete a majority of small hydrophilic molecules and their clearance, secretion, or fixation in the kidney is quantifiable. When a renal marker in plasma is filtered through the glomeruli, the accumulation of the filtrate in the Bowman s capsule. One or more of the following events may occur in the renal tubule once a marker is filtered or is in plasma [171] ... 

The NIR region is of great interest for pharmaceutical applications. NIRS is fast, nondestructive, and cost effective. Samples require no preparation and can be measured as such, intact and available for further analysis. NIRS can be performed in-, on-, and offline. Also, glass fiber optics can be used to perform remote analysis, thus bringing radiation directly to the sample. Many more advantages can be cited when considering the practical use of NIR in a pharmaceutical process, depending on the particular objective. 

Raman is simple to use and require virtually no sample preparation. The vibrational spectra of polymer samples in their original forms can be measured and casting or hotpressing of the material into thin films (commonly used for FTIR measurements), a very time-consuming procedure that can affect the original structure of the material, are not required. It also offers remote analysis capabilities if combined with fibre optics [108, 109]. Accurate determination of contaminant content in recycled polymeric resins have been reported in the literature [110, 111, 112]. 

Absorption bands in the visible and near-infrared spectra of Moon and Mars — correlate well with a narrow choice of minerals. — they provide a perhaps unique means of remote analysis of some of the abundant mineral phases on the surfaces of the bodies. 

The last two decades have seen some spectacular achievements in analytical science the placing of the environmental revolution on a sound basis by the routine determination of p.p.m. or p.p.b. levels of pollutants in the atmosphere, hydrosphere and biosphere the routine testing of athletes and race horses for traces of stimulants the remote analysis of the surface of the Moon and Mars and the atmosphere of Venus, etc. It has also been a period when the normal criteria for acceptable limits of impurities has dropped from the level of per cent to p.p.b., when non-destructive testing has become routine and when samples can be so small that even destructive methods of analysis scarcely have a deleterious effect on bulk of the material from which the sample is taken. In short, the nature of analysis has changed greatly. 

Non-radiometric methods offer a variety of features and their use may be favoured for reasons other than improved sensitivity or isotopic selectivity. They can, in some instances, be used to perform analyses with less sample preparation and greater speed or sample throughput, and allow remote analysis or provide elemental or isotopic maps or depth profiles (McMahon, 1992). 

The production of phosphorus trichloride from phosphorus and chlorine is an important step in the manufacture of a number of agrochemical products. Raman spectroscopy has been used to monitor the reaction and control the raw material feed rates. This maximises production of phosphoras trichloride, minimizes the formation of phosphorus pentachloride and ensures safe operation when plant shut-down periods are needed. Remote analysis is achieved using optical fibers to provide a safer operation and a more rapid analysis than was previously possible [29, 30]. 

Phase-resolved fluorlmetric measurement had also been employed previously for the simultaneous quantification of the individual components in complex mixtures (7). However, as with most spectroscopic techniques it has not been used for remote analysis. 

Near-infrared (NIR) spectroscopy lends itself to the pharmaceutical quality control laboratory [6, 7]. The development of fibre optic probes for remote analysis has lead to the expansion of its use in the pharmaceutical industry. Libraries of the NIR spectra of compounds conunonly used in the pharmaceutical industry are available. Quantitative analysis can also be effectively carried out by using multivariate techniques such as principal component analysis (PCA). 

Panne U, Neuhauser RE, Haisch C, Fink H, and Niessner R (2002) Remote analysis of a mineral melt by laser-induced plasma spectroscopy. Applied Spectroscopy 56 375-380. 

Remote analysis of solids is possible through the use of fiber-optic probes such as the FlexIR NIR fiber-optic accessory described in the previous section. The probe tip is simple touched to the sample, in drums or through packaging, and the spectrum collected. This eliminates sample preparation, speeds up analyses, and minimizes exposure of the analyst to large amounts of materials. 

Samples can be analyzed through glass or a polymer packaging Laser light and Raman scattered light can be transmitted by optical fibers over long distances for remote analysis Raman spectra can be collected from a very small volume (< 1 pm in diameter)... 

The recording of Raman spectra of gases is not straightforward because of the low number density of molecules in the gaseous or vapour state. On the other hand resolved pure rotational and rotation-vibrational spectra provide information on molecular structures which can not be obtained from spectra of condensed phases. Through the determination of moments of inertia from the rotational structure atomic distances in molecules are deduced. Moreover the composition of gas mixtures can be investigated, including remote analysis of the atmosphere. 

HW Schrotter. Raman and infrared spectroscopic techniques for remote analysis of the atmosphere. In RJH Clark, RE Hester, eds. Advances in Infrared and Raman Spectroscopy, Vol. 8. London Heyden, 1981, pp 1-51. 

Typically, environmental analysis is categorized according to the media in which the analysis is made, namely air, water, and soil. Although the advantages of RS are perhaps most important for aqueous systems, the technique has also been widely applied to air analysis, especially in the remote analysis of pollutants, with a range of up to several kilometers. In fact, approximately 150 articles devoted to this topic have been published since 1990. Many of these studies involve Raman-based light detection and ranging (LIDAR). In particular, smoke-stack emission studies have been an area of considerable... 

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