Laser-induced Photoacoustic Spectroscopy Research Articles

Photoacoustic Determination of Trace Species Adsorbed on a Single Microparticle

Laser-induced photoacoustic spectroscopy was applied in order to determine trace amounts of iron adsorbed onto the surface of a solid resin Amberlite XAD-2 microparticle of 300μm in diameter as an oxine (8-quinolinol) complex. The photoacoustic measurements were carried out with a single particle in order to avoid any scattering effects. The signal magnitude depended on the iron concentration, which ranged from 5×10-3 to 3mg for one gram of resin. This dependence deviated from linearity as the concentration became larger than 40μg per gram of resin. The nonlinear behavior was regarded as being a saturation phenomenon resulting from the spatial variation of the optical thickness due to the sample′s spherical form. The saturation effect could be eliminated by focusing the incident beam to a size sufficiently small with respect to the particle diameter.

Comparison of photoacoustic spectroscopy, conventional absorption spectroscopy, and potentiometry as probes of lanthanide speciation

The authors measured the stability constants of praseodymium acetate and oxydiacetate complexes by laser-induced photoacoustic spectroscopy, conventional UV-visible absorption spectroscopy, and pH titration. For the spectroscopic studies, changes in the free Pr absorption peaks at 468 and 481 nm were monitored at varying ligand concentrations. The total Pr concentration was 1 {times} 10{sup {minus}4} M in solutions used for the photoacoustic studies and 0.02 M for conventional spectroscopy. For the pH titrations, we used solutions whose Pr concentrations varied from 5 {times} 10{sup {minus}3} to 5 {times} 10{sup {minus}2} M, with total ligand-to-metal ratios ranging from 1 to 10. A comparison of the results obtained by the three techniques demonstrates that photoacoustic spectroscopy can give the same information about metal-ligand speciation as more conventional methods. It is particularly suited to those situations where the other techniques are insensitive because of limited metal concentrations.

Laser induced photoacoustic spectroscopy in liquid samples: temperature and solvent effects

Laser induced photoacoustic spectroscopy (LIPAS) has been confirmed as an analytical tool, suitable for the determination of inorganic and organic species in aqueous and organic solvents, reaching detection limits two orders of magnitude lower than those obtained with conventional spectrophotometry.

Speciation of actinoids by laser-induced photoacoustic spectroscopy.

Laser-induced photoacoustic spectroscopy (LPAS) has been developed for the direct speciation of actionoids in solution with the minimal disturbance of species equilibria. The speciation of actinoids is defined as the elucidation of the individual physical and chemical forms of actinoids in a sample. In the present review, the characteristics of the optical absorption spectra of actinoids, theprinciple, theory, and construction of the LPAS system are described in detail with its application to the speciation of actinoids in aqueous solution.

Laser-induced chemistry for radioactive solution.

The paper reviws a potential role of laser-induced chemistry in the treatment of radioactive solutions. The first part describes the application of laser-induced chemistry to nuclear fuel reprocessing. A major advantage of laser-induced chemical methods is substitution of light energy for quantities of chemical reagents. The laser-induced redox reactions of U, Np, and Pu are of interest for advanced reprocessing. The second part deals with analytical methods of actinide characterization in natural enyironments. Speciation capabilities of different laser spectroscopies are reported with some examples. The methods under discussion are laser-induced photoacoustic spectroscopy, laserinduced thermal lensing spectroscopy, and Doppler electrophoretic light scattering analysis.

A Direct Speciation of Transuranium Elements in Natural Aquatic Systems by Laser-Induced Photoacoustic Spectroscopy

A Direct Speciation of Transuranium Elements in Natural Aquatic Systems by Laser-Induced Photoacoustic Spectroscopy

Speciation of Transuranic Ions in Groundwater by Laser-Induced Photoacoustic Spectroscopy (LPAS)

ABSTRACTThe speciation of the Am(III) ion in various chemical states is illustrated using laser-induced photoacoustic spectroscopy (LPAS). Based on these reference LPAS spectra, the actual chemical states of Am(III) in one of Gorleben groundwaters are systematically verified. The a-radiolytic oxidation of Am(III) to Am(V) in the concentrated NaCl solution and their carbonate complexation are also speciated for the purpose of demonstration.

Americium colloid generation in groundwaters and its speciation by laser-induced photoacoustic spectroscopy

Abstract The generation of americium colloids in groundwaters rich and poor in humic substances is investigated. The size fractionation is realized by ultrafiltration as well as by ultracentrifugation, and the colloid composition is characterized by analysis of the dissolved organic carbon, neutron activation analysis and inductively coupled plasma atom emission spectrometry. The process responsible for the generation of americium pseudocolloids in two selected groundwaters is demonstrated with the help of laser-induced photoacoustic spectroscopy which provides high speciation sensitivity.

Humic Colloid Generation of Transuranic Elements in Groundwater and Their Migration Behaviour

AbstractThe generation of humic colloids of Am(III) has been investigated in Gorleben groundwaters containing different amounts of humic substances. Dissolved organic carbon (DOC) in these groundwaters consists mainly of humic acid and fulvic acid, which is present in a colloidal form through aggregation with trace heavy metal ions of groundwater constituents. Concentrations of these heavy metal ions are proportional to the DOC concentration. The generation of Am(III) pseudocolloids through geochemical interactions with humic colloids in different groundwaters is quantified by ultrafiltration as well as ultracentrifugation by the aid of radiometric concentration measurements. The speciation of dissolved Am(III) species in groundwaters is carried out by laser induced photoacoustic spectroscopy (LPAS).

Quantitative Depth Profiling of Biporous Nickel Electrodes by Frequency-Domain Laser-Induced Photoacoustic Spectroscopy

Frequency-domain Photoacoustic Spectroscopy (PAS) was used with a He-Ne laser exciting beam to probe commercially available, powdered and pressed nickel electrodes with dual-porosity profiles. The frequency response of the electrodes was shown to be capable of providing quantitative information about the thermal conductivity and diffusivity of each of the two porous layers, provided the depth of the porosity junction in the electrode bulk is known. The reasonable agreement of the experimental data with a one-dimensional mathematical model of the photoacoustic response from a two-layer, photoacoustically saturated, continuous system indicates that powdered and pressed nickel electrodes behave photoacoustically approximately like a simple continuous composite-layer solid. This conclusion, together with experimental PAS results from uniporous electrodes, emphasizes the high potential of photoacoustic spectroscopy as a nondestructive, depth profiling, analytical technique for the determination of complex porosity profiles in electrodes manufactured for use in electrochemical energy conversion devices, such as fuel cells.

Solubility and Colloid Generation of Plutonium from Leaching of a HLW Glass in Salt Solutions

AbstractSolubilities of Pu from leaching of a simulated HLW glass (C31–3-EC) spiked with 5 wt % Pu and from PuO2 are determined in salt solutions of different NaCl concentration and in groundwaters which are representative for the Gorleben area. Th.e leaching experiment is carried out either in an autoclave at 200 °C or under normal conditions (1 atm, 25°C). Solubilities of Pu in all investigated solutions are observed to be considerably higher than the values known from theoretical estimates. The predominant Pu species in solutions are found to be microcolloids, which are characterized by means of ultrafiltration and pulsed laser-induced photoacoustic spectroscopy.

Analysis of turbid solutions by laser-induced photoacoustic spectroscopy

Analysis of turbid solutions by laser-induced photoacoustic spectroscopy

Observation of semiconductor electrode-dye solution interface by means of fluorescence and laser-induced photoacoustic spectroscopy

Observation of semiconductor electrode-dye solution interface by means of fluorescence and laser-induced photoacoustic spectroscopy

Simultaneous determination of mixtures in liquid by laser-induced photoacoustic spectroscopy

Simultaneous determination of mixtures in liquid by laser-induced photoacoustic spectroscopy

Laser-induced photoacoustic spectroscopy of some rare earth ions in aqueous solutions

Laser-induced photoacoustic spectroscopy of some rare earth ions in aqueous solutions