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Applied Spectroscopy

Winfried Nischkauer, Andrei Izmer, Marie-Alexandra Neouze, Frank Vanhaecke, Andreas Limbeck
A combination of analyte pre-concentration using dispersed particle extraction (DPE) and dried-droplet laser ablation inductively coupled mass spectrometry (LA-ICP-MS) was developed with the aim to quantify Pt and Pd in urban particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5). The PM2.5 aerosol was collected on cellulose ester filters during a sampling period of three days, with sampling intervals of 4 h only. Each of the filters was chemically digested, and the resulting solution was pre-concentrated using DPE...
July 2017: Applied Spectroscopy
Leonardo Bennun
A new smoothing method for improvement on the quantification of spectral signals, which requires the previous knowledge of the functions that should be quantified, is presented. These functions are used as weighted coefficients in the proposed smoothing algorithm. This method is extremely effective in reducing the scatter of signals obtained by the multichannel analyzer and it could be applied in atomic and nuclear spectroscopies, preferably to these techniques where net counts are a linear function of the acquisition time, like total reflection X-ray fluorescence, micro X-ray fluorescence, etc...
July 2017: Applied Spectroscopy
Chafia Benmouhoub, Bernard Gauthier-Manuel, Ameur Zegadi, Laurent Robert
Due to its impressive optical properties, lithium niobate (LiNbO3) is considered to be one of the most important ferroelectric materials. Its uses in sensing platforms require functionalization at the surface to enable the capture and quantifying of molecules. The current paper aims to demonstrate the covalent bonding of aminosilane layers to the LiNbO3 surface. Fourier transform infrared (FT-IR) analysis reveals the presence of an NbO-Si bond observable as a shoulder at the same wavenumber (975 cm(-1)) on the surfaces of LiNBO3 as well as on those of Nb2O5, using 3-(aminopropyl)trimethoxysilane (APTMS) or 3-(aminopropyl)methyldimethoxysilane (APDMS) precursors...
July 2017: Applied Spectroscopy
Valery Sizikov, Denis Sidorov
An inverse problem in spectroscopy is considered. The objective is to restore the discrete spectrum from observed spectrum data, taking into account the spectrometer's line spread function. The problem is reduced to solution of a system of linear-nonlinear equations (SLNE) with respect to intensities and frequencies of the discrete spectral lines. The SLNE is linear with respect to lines' intensities and nonlinear with respect to the lines' frequencies. The integral approximation algorithm is proposed for the solution of this SLNE...
July 2017: Applied Spectroscopy
Camiel H van Hoorn, Carlos Wessels, Freek Ariese, Arjan J G Mank
A fast high-resolution screening method for reactive surfaces is presented. Atomic force microscopy (AFM) and surface-enhanced Raman spectroscopy (SERS) are combined in one method in order to be able to obtain both morphological and chemical information about processes at a surface. In order to accurately align the AFM and SERS images, an alignment pattern on the substrate material is exploited. Subsequent SERS scans with sub-micron resolution are recorded in 30 min per scan for an area of 100 × 100 µm(2) and are accompanied by morphological information, supplied by a fast AFM, of the same area...
July 2017: Applied Spectroscopy
Xunchen Liu, Inseok Chae, Naresh Miriyala, Dongkyu Lee, Thomas Thundat, Seonghwan Kim
Broadband mid-infrared molecular spectroscopy is essential for detection and identification of many chemicals and materials. In this report, we present stand-off mid-infrared spectra of 1,3,5-trinitro-1,3,5-triazine or cyclotrimethylene trinitramine (RDX) residues on a stainless-steel surface measured by a broadband external cavity quantum cascade laser (QCL) system. The pulsed QCL is continuously scanned over 800 cm(-1) in the molecular fingerprint region and the amplitude of the reflection signal is measured by either a boxcar-averager-based scheme or a lock-in-amplifier-based scheme with 1 MHz and 100 kHz quartz crystal oscillators...
July 2017: Applied Spectroscopy
Sachie Kudo, Hiromi Ogawa, Eri Yamakita, Shio Watanabe, Toshiyuki Suzuki, Satoru Nakashima
Infrared (IR) microspectroscopy combined with a quartz crystal microbalance (QCM) together with an original relative humidity (RH) control system has been developed for studying water adsorption on a collagen film. The adsorbed water weights measured by QCM are almost similar for wetting and drying processes at 28 ℃, indicating that the collagen film is close to the water adsorption/desorption equilibria. A broad OH + NH stretching band area (3000-3700 cm(-1)) in the IR spectra of the collagen film increased linearly with the adsorbed weight until about 1...
July 2017: Applied Spectroscopy
Christopher H Drozdowski, Jafar Gharavi-Naeini, Nathan A Stump
Divalent samarium incorporated in a barium octaborate matrix prepared by firing homogeneous precipitates has been studied with emission spectroscopy. One of the samarium sites associated with this product exhibits an extremely strong temperature dependence upon using an excitation wavelength of 532 nm. This effect allows for specific differentiation between the two major Sm(II) sites associated with this compound. Based on the assignment of the emission features to specific sites, the symmetry of the first samarium environment is thought to be C3 or C3v while that associated with the second site appears to be C2v...
July 2017: Applied Spectroscopy
Stephen Giguere, Thomas Boucher, C J Carey, Sridhar Mahadevan, M Darby Dyar
The task of proper baseline or continuum removal is common to nearly all types of spectroscopy. Its goal is to remove any portion of a signal that is irrelevant to features of interest while preserving any predictive information. Despite the importance of baseline removal, median or guessed default parameters are commonly employed, often using commercially available software supplied with instruments. Several published baseline removal algorithms have been shown to be useful for particular spectroscopic applications but their generalizability is ambiguous...
July 2017: Applied Spectroscopy
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July 2017: Applied Spectroscopy
Tomas Leffler, Christian Brackmann, Marcus Aldén, Zhongshan Li
Laser-induced photofragmentation fluorescence has been investigated for the imaging of alkali compounds in premixed laminar methane-air flames. An ArF excimer laser, providing pulses of wavelength 193 nm, was used to photodissociate KCl, KOH, and NaCl molecules in the post-flame region and fluorescence from the excited atomic alkali fragment was detected. Fluorescence emission spectra showed distinct lines of the alkali atoms allowing for efficient background filtering. Temperature data from Rayleigh scattering measurements together with simulations of potassium chemistry presented in literature allowed for conclusions on the relative contributions of potassium species KOH and KCl to the detected signal...
June 2017: Applied Spectroscopy
Krystal L Sly, John C Conboy
A novel application of second harmonic correlation spectroscopy (SHCS) for the direct determination of molecular adsorption and desorption kinetics to a surface is discussed in detail. The surface-specific nature of second harmonic generation (SHG) provides an efficient means to determine the kinetic rates of adsorption and desorption of molecular species to an interface without interference from bulk diffusion, which is a significant limitation of fluorescence correlation spectroscopy (FCS). The underlying principles of SHCS for the determination of surface binding kinetics are presented, including the role of optical coherence and optical heterodyne mixing...
June 2017: Applied Spectroscopy
Daniel Martin, Alicia G Gonzalvez, Rocio Mateos Medina, Angel González Ureña
This work reports on a combined experimental and theoretical investigation on the carotenoid Raman signal in several tomato fruits during their postharvest time evolution and ripening. Both resonant (180°) backscattering and polarized (90°) Raman scattering were used to monitor the most prominent bands of carotenoid (lycopene and β-carotene) evolution in different tomato varieties. Relevant findings of the present investigations were that while the depolarization ratio of the ν1 band hardly changed with time, the Raman ν1 band intensity did change showing a similar pattern for all tomatoes investigated...
June 2017: Applied Spectroscopy
Kevin Buckley, Alan G Ryder
The production of active pharmaceutical ingredients (APIs) is currently undergoing its biggest transformation in a century. The changes are based on the rapid and dramatic introduction of protein- and macromolecule-based drugs (collectively known as biopharmaceuticals) and can be traced back to the huge investment in biomedical science (in particular in genomics and proteomics) that has been ongoing since the 1970s. Biopharmaceuticals (or biologics) are manufactured using biological-expression systems (such as mammalian, bacterial, insect cells, etc...
June 2017: Applied Spectroscopy
Jacopo Parravicini, Maurizio Acciarri, Alberto Lomuscio, Matteo Murabito, Alessia Le Donne, Andrea Gasparotto, Simona Binetti
In the thin film solar cells domain, copper indium galium (di)selenide (CIGS) is a material with well-established photovoltaic purpose. Here the presence of a suitable [Ga]/([Ga]+[In]) (GGI) in-depth profile has proved to play a key role in the performance of cells. The implementation of a routine method based on reliable but easily available experimental techniques is mandatory to obtain information on the GGI profile of any CIGS layer, in order to achieve high efficiency chalcogenide layers. In this vein, we here propose and systematically test a simple method for the GGI profile determination based on repeated bromine etching of CIGS thin films followed by Raman analysis of the A1 peak position...
June 2017: Applied Spectroscopy
Nobutaka Shioya, Takafumi Shimoaka, Richard Murdey, Takeshi Hasegawa
Infrared (IR) p-polarized multiple-angle incidence resolution spectrometry (pMAIRS) is a powerful tool for analyzing the molecular orientation in an organic thin film. In particular, pMAIRS works powerfully for a thin film with a highly rough surface irrespective of degree of the crystallinity. Recently, the optimal experimental condition has comprehensively been revealed, with which the accuracy of the analytical results has largely been improved. Regardless, some unresolved matters still remain. A structurally isotropic sample, for example, yields different peak intensities in the in-plane and out-of-plane spectra...
June 2017: Applied Spectroscopy
Ionela Raluca Comnea-Stancu, Karin Wieland, Georg Ramer, Andreas Schwaighofer, Bernhard Lendl
This work was sparked by the reported identification of man-made cellulosic fibers (rayon/viscose) in the marine environment as a major fraction of plastic litter by Fourier transform infrared (FT-IR) transmission spectroscopy and library search. To assess the plausibility of such findings, both natural and man-made fibers were examined using FT-IR spectroscopy. Spectra acquired by transmission microscopy, attenuated total reflection (ATR) microscopy, and ATR spectroscopy were compared. Library search was employed and results show significant differences in the identification rate depending on the acquisition method of the spectra...
May 2017: Applied Spectroscopy
Arthur L Miller, Andrew Todd Weakley, Peter R Griffiths, Emanuele G Cauda, Sean Bayman
In order to help reduce silicosis in miners, the National Institute for Occupational Health and Safety (NIOSH) is developing field-portable methods for measuring airborne respirable crystalline silica (RCS), specifically the polymorph α-quartz, in mine dusts. In this study we demonstrate the feasibility of end-of-shift measurement of α-quartz using a direct-on-filter (DoF) method to analyze coal mine dust samples deposited onto polyvinyl chloride filters. The DoF method is potentially amenable for on-site analyses, but deviates from the current regulatory determination of RCS for coal mines by eliminating two sample preparation steps: ashing the sampling filter and redepositing the ash prior to quantification by Fourier transform infrared (FT-IR) spectrometry...
May 2017: Applied Spectroscopy
Patrick D Barnett, S Michael Angel
A spatial heterodyne Raman spectrometer (SHRS) with millimeter-sized optics has been coupled with a standard cell phone camera as a detector for Raman measurements. The SHRS is a dispersive-based interferometer with no moving parts and the design is amenable to miniaturization while maintaining high resolution and large spectral range. In this paper, a SHRS with 2.5 mm diffraction gratings has been developed with 17.5 cm(-1) theoretical spectral resolution. The footprint of the SHRS is orders of magnitude smaller than the footprint of charge-coupled device (CCD) detectors typically employed in Raman spectrometers, thus smaller detectors are being explored to shrink the entire spectrometer package...
May 2017: Applied Spectroscopy
Anna P M Michel, Jason Kapit
With the recent development of deep ultraviolet (DUV) light emitting diodes (LEDs) comes the possibility of targeting absorption bands of several gases, including sulfur dioxide (SO2). SO2 has strong absorption bands in the 300 nm spectral region. The low cost and small size of DUV LEDs, coupled with their spectral coverage, makes them viable sources for new gas sensors. Here, we demonstrate the capability to use absorption spectroscopy with a balanced detection scheme using a 300 nm DUV LED source for SO2 detection at concentrations ranging from less than 1 ppm to 50 ppm...
May 2017: Applied Spectroscopy
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