Detection of hydrogen

Detection of hydrogen is a particularly important problem for astrochemists because to a first approximation all visible matter is hydrogen. The hydrogen molecule is the most abundant molecule in the Universe but it presents considerable detection problems due to its structure and hence spectroscopy. Hydrogen does not possess a permanent dipole moment and so there is no allowed rotation or vibration spectrum and all electronic spectrum transitions are in the UV and blocked by the atmosphere. The launch of the far-UV telescope will allow the detection of H2 directly but up to now its concentration has been inferred from other measurements. The problem of detecting the H atom, however, has been solved using a transition buried deep in the hyperflne structure of the atom. 

A recent success in the detection of H species has been that of the molecular ion H3+. All of the models of ion-molecule chemistry in hydrogen-dominated regions are controlled by reactions of H3+ but until recently the H2+ molecular ion had not been detected. However, the modes of vibration of H3 1 provide for an allowed IR transition at 3.668 pin used for its detection. These ro-vibrational transitions have now been observed in a number of places, including the interstellar medium and in the aurorae of Jupiter. Not all astronomical detection and identification problems have been solved, however, and the most annoying and compelling of these is the problem of diffuse interstellar bands. 

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A method of detecting herbicides is proposed the photosynthetic herbicides act by binding to Photosystem II (PS II), a multiunit chlorophyll-protein complex which plays a vital role in photosynthesis. The inhibition of PS II causes a reduced photoinduced production of hydrogen peroxide, which can be measured by a chemiluminescence reaction with luminol and the enzyme horseradish peroxidase (HRP). The sensing device proposed combines the production and detection of hydrogen peroxide in a single flow assay by combining all the individual steps in a compact, portable device that utilises micro-fluidic components. 

Rev. Lett. 56,1377,1986. Detection of hydrogen clustering in amorphous hydrogenated silicon by a special technique of dipolar spectroscopy, mul-dple-quantum NMR. 

Elastic recoil spectrometry (ERS) is used for the specific detection of hydrogen ( H, H) in surface layers of thickness up to approximately 1 pm, and the determination of the concentration profile for each species as a function of depth below the sample s surfece. When carefully used, the technique is nondestructive, absolute, fast, and independent of the host matrix and its chemical bonding structure. Although it requires an accelerator source of MeV helium ions, the instrumentation is simple and the data interpretation is straightforward. 

Unexpectedly strong intermolecular hydrogen bonding has been reported by IR spectroscopic studies for tetrahydro-4,7-phenanthroline-l,10-dione-3,8-dicarboxylic acids, which exist in the oxo-hydroxy form 165 in both solid state and in solution [78JCS(CC)369].Tlie conclusion was based on comparison of B-, C-, and D-type bands for 165 and their dimethyl esters (detection of hydrogen bonding) and on analysis of IR spectra in the 6 /xm region (pyridine- and pyridone-like bands). 

Tamaoku and colleagues presented an efficient enzymatic photometric determination of hydrogen peroxide ffiat is essentially a color reaction resulting from the oxidative condensation of A/-ethyl-A/-(2-hydroxy-3-sulfopropyl)aniline derivatives wiffi 4-aminoantipyrine in the presence of hydrogen peroxide and peroxidase (82CPB2492). A similar calorimetric detection of hydrogen peroxide has been patented (83GEP3301470). 

Ultrasonics has been utilised in several versions of pipeline inspection vehicle see section below). The use of ultrasonics for detection of hydrogen damage in steels has been reported"". ... 

Lyon, S. B. and Fray, D. J., Detection of Hydrogen Generated by Corrosion Reactions using a Solid Electrolyte Probe , Materials Performance, 24, 4, 23-25, April (1984)... 

In order to develop more informative and direct method of studying the spillover effect of active particles, the authors of [37] suggested to use the sensor method of detecting migrating particles based on separation of sensor and emitter (donor) of active particles. The latter consists of small metal globules, or clusters (with a diameter of about 20-30 A) of Pt, Pd, Ni, etc. (activator) deposited on quartz or sapphire (AI2O3) plate in the form of a strip less than 1 cm wide. The sensor for detection of hydrogen atoms consisted of a zinc oxide strip (with a width of about 0.1 cm and thickness wlOO nm) deposited on the same plate at a distance of 0.03 or 0.6 cm (two versions) from the inner boundaries of activator strips [38]. 

Stetter JR, Sedlak JM, Blurton KF. 1977. Electrochemical gas chromatographic detection of hydrogen sulfide at PPM and PPB levels. J Chromatogr Sci 15 125-128. 

Electrochemical biosensors based on detection of hydrogen peroxide at platinized electrodes were found to be more versatile allowing a decrease in detection limit down to 1 i,mol L 1 [109]. However, all biological liquids contain a variety of electrochemically easily oxidizable reductants, e.g. ascorbate, urate, bilirubin, catecholamines, etc., which are oxidized at similar potentials and dramatically affect biosensor selectivity producing parasitic anodic current [110]. 

Despite the possibility for detection of hydrogen peroxide down to 10 7 mol L-1 achieved, both clinical diagnostics and environmental control in certain cases require... 

Among different approaches providing operation of the oxidase-based biosensors, the detection of hydrogen peroxide production was found to be the most progressive one, allowing detection of low levels of analytes [107], However, the detection of H202 has to be carried out at low potentials in order to reduce the interference of easily oxi-dizable compounds [110]. 

To make the most advantageous glucose biosensor, it is important to combine the best transduction principle with the best immobilization protocol. As mentioned, the most progressive way to couple the oxidase and the electrode reaction is a low potential detection of hydrogen peroxide. Among available H202 transducers, Prussian blue is the most advantageous one. 

W.B. Nowall and W.G. Kuhr, Detection of hydrogen peroxide and other molecules of biological importance at an electrocatalytic surface on a carbon fiber microelectrode. Electroanalysis 9, 102-109 (1997). 

S. Varma and B. Mattiasson, Amperometric biosensor for the detection of hydrogen peroxide using catalase modified electrodes in polyacrylamide. J. Biotech. 119, 172-180 (2005). 

Detection of Hydrogen Peroxide Generated in a Postcolumn Reactor... 

Joel, V. Monzon Hernandez, D., Fast detection of hydrogen with nano fiber tapers coated with ultra thin palladium layers, Opt. Express 2005, 13, 5087 5092... 

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