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Applied Spectroscopy

Pieter Samyn, Dries Vandamme, Peter Adriaensens, Robert Carleer
No abstract text is available yet for this article.
September 18, 2018: Applied Spectroscopy
Bruno Debus, Satoshi Takahama, Andrew Weakley, Kelsey Seibert, Ann Dillner
No abstract text is available yet for this article.
September 18, 2018: Applied Spectroscopy
Yoshihiro Deguchi, Minchao Cui, Zhenzhen Wang, Seiya Tanaka, Yuki Fujita, Shengdun Zhao
No abstract text is available yet for this article.
September 12, 2018: Applied Spectroscopy
Xiongfei Chen, Muhua Liu, Haichao Yuan, Shuanggen Huang, Jinjiang Tao, Jinhui Zhao
Estrogen residues, including diethylstilbestrol in chicken, are one of the main food safety concerns all over the world owing to a series of negative effects on the human body. Surface-enhanced Raman spectroscopy (SERS) coupled with multivariate analysis was applied to detect rapidly diethylstilbestrol residues in chicken. The detection conditions, including the sizes of colloidal gold nanoparticles (Au NPs) and the additional amounts of Au NPs, chicken extract containing diethylstilbestrol, and magnesium sulfate solution, as well as the adsorption time, were optimized by a single factor experiment to obtain a better detection effect of diethylstilbestrol residues in chicken...
September 11, 2018: Applied Spectroscopy
Andrew J Parrott, Paul Dallin, John Andrews, Peter M Richardson, Olga Semenova, Meghan E Halse, Simon B Duckett, Alison Nordon
Raman spectroscopy has been used to provide a rapid, noninvasive, and nondestructive quantification method for determining the parahydrogen fraction of hydrogen gas. The basis of the method is the measurement of the ratio of the first two rotational bands of hydrogen at 355 cm-1 and 586 cm-1 corresponding to parahydrogen and orthohydrogen, respectively. The method has been used to determine the parahydrogen content during a production process and a reaction. In the first example, the performance of an in-house liquid nitrogen cooled parahydrogen generator was monitored both at-line and on-line...
September 11, 2018: Applied Spectroscopy
Tejaswini Rama Bangalore Ramakrishna, Daniel Patrick Killeen, Tim David Nalder, Susan Nellette Marshall, Wenrong Yang, Colin James Barrow
The surface chemistry of graphene oxide (GO) can be modified by the chemical reduction of oxygen-containing groups using L-ascorbic acid (L-AA). Being able to "tune" the surface hydrophobicity of GO in a controlled manner, with a well-defined level of reduction, provides a valuable tool for understanding and controlling interactions with hydrophobic surfaces. Numerous analytical and chemical methods have been used to determine the extent of reduction in chemically reduced graphene oxide (CRGO) samples...
September 10, 2018: Applied Spectroscopy
Agathi-Anthoula Kaminari, Stamatis C Boyatzis, Athina Alexopoulou
The question for discriminating iron gall inks is addressed by correlating their infrared (IR) spectra in liquid and dried states with the materials used in their formulations and considering their possible interactions. A series of laboratory inks were prepared according to historic recipes, mainly found in 19th-century documents, and were accordingly studied using Fourier transform infrared (FT-IR) spectroscopy. All ink formulations were based on Aleppo galls, ferrous sulfate, and gum arabic at variable proportions, with various added components, such as alum, vinegar, glycerol, sugar, silver nitrate, cloves, and white wine...
August 30, 2018: Applied Spectroscopy
Naoto Morifuji, Satoru Nakashima
Infrared (IR) spectral changes with time of biogenic and inorganic silica have been examined using in situ IR micro-spectroscopy by using an original hydrothermal diamond cell. Centric diatoms (diameters = 100-350 µm) and silica gels (C-300, Wako Chemicals) were heated at 125-185 ℃ range with a pressure of 3 MPa. Decreases of 950 cm-1 (Si-OH) peak heights could be fitted by a combination of exponential and linear decreases (y = A1 exp (-k1 t) - k0 t + A0 ). The first-order rate constants k1 [s-1 ] for Si-OH decreases of diatoms and silica gels are similar but the activation energy was lower for diatoms (61 kJċmol-1  < 106 kJċmol-1 )...
August 30, 2018: Applied Spectroscopy
Cameron M Rekully, Stefan T Faulkner, Ergun Kara, Tammi L Richardson, Timothy J Shaw, M L Myrick
The use of rotating filter wheels is common in photometric applications. Traditional filter wheel designs typically exhibit a number of filter openings spaced evenly about the circumference of the wheel. In this work we examine a number of shortcomings of this traditional filter design in measurements of phytoplankton fluorescence made with our fluorescence imaging photometer (FIP). We present an alternative asymmetric wheel design that offers a number of advantages over the traditional design as well as a new processing algorithm designed to accommodate convolution of signals from adjacent channels inherent in measurements collected with the asymmetric design...
August 23, 2018: Applied Spectroscopy
Tyler A Morhart, Stuart Read, Garth Wells, Michael Jacobs, Scott M Rosendahl, Sven Achenbach, Ian J Burgess
A custom-designed optical configuration compatible with the use of micromachined multigroove internal reflection elements (μ-groove IREs) for attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy and imaging applications in microfluidic devices is described. The μ-groove IREs consist of several face-angled grooves etched into a single, monolithic silicon chip. The optical configuration permits individual grooves to be addressed by focusing synchrotron sourced IR light through a 150 µm pinhole aperture, restricting the beam spot size to a dimension smaller than that of the groove walls...
August 23, 2018: Applied Spectroscopy
Yu Lei, Xi Huang, Xuemei Guo, Mengmeng Wang, Shichao Zhu, Gang Jin
At present, there is a widespread phenomenon that product quality is difficult to monitor during the process of polymer melt modification such as blending, filling, and reinforcement. In consideration of this problem, this paper proposes an in-line Raman spectroscopy technique for measuring dispersion uniformity of polystyrene (PS) in polypropylene (PP)/PS blends during melt extrusion. On the basis of the optimal partial least squares (PLS) calibration model for quantitative determination of PS content in PP/PS, the fluctuations of PS content in extruding PP/PS with a mass percentage of 70 : 30 at different screw rotation speeds were predicted...
August 23, 2018: Applied Spectroscopy
Osazonamen J Igbinosun, Adam P Bruckner, Stephen E Wood
Results and analysis of internal reflection spectral absorbance experiments are reported for near-infrared (NIR) spectra obtained using an optical fiber sensor system. We present a preliminary study to diagnose the efficacy of our fiber optic system to observe and distinguish various phases of water, i.e., ice, liquid, and adsorbed. This study was motivated by the need for a technique capable of obtaining soil water content measurements in real time and in situ, at low humidity conditions for simulation studies of planetary bodies such as Mars...
August 23, 2018: Applied Spectroscopy
Md Nahidul Islam, Glenn Nielsen, Søren Stærke, Anders Kjær, Bjarke Jørgensen, Merete Edelenbos
A firm texture of dry onions is important for consumer acceptance. Both the texture and dry matter content decline during storage, influencing the market value of onions. The main goal of this study was to develop predictive models that in future might form the basis for automated sorting of onions for firmness and dry matter content in the industry. Hyperspectral scanning was conducted in reflectance mode for six commercial batches of onions that were monitored three times during storage. Mean spectra from the region of interest were extracted and partial least squares regression (PLSR) models were constructed...
August 21, 2018: Applied Spectroscopy
Jie Huang, Tielin Shi, Bo Gong, Xiaoping Li, Guanglan Liao, Zirong Tang
The Raman background arising from optical fiber materials poses a critical problem for fiber optic surface-enhanced Raman spectroscopy (SERS). A novel filter is developed to fit the optical fiber background from the measured SERS spectrum of the target sample. The general model of the filter is built by incorporating a weighted term of matching the similarity between the estimated background spectrum and the measured background spectrum into the classic Savitzky-Golay (SG) smoothing filter model. Through respectively selecting Euclidean cosine coefficient (ECos) and Pearson correlation coefficient (PCor) as the similarity index, two different models of the weighted SG smoothing filter are derived and named as SG-ECos and SG-PCor accordingly...
August 15, 2018: Applied Spectroscopy
Farzad Yousefi, Shital Kandel, Nancy Pleshko
Methacrylated hyaluronic acid (MeHA) has been used extensively in tissue engineering and drug delivery applications. The degree of methacrylation (DM) of HA impacts hydrogel crosslinking, which is of pivotal importance for cell interactions. The methacrylation reaction occurs over several hours, and DM is currently assessed post reaction and after dialysis of the solution, using nuclear magnetic resonance (1 H NMR) data. Thus, there is little control over exact DM in a specific reaction. Here, infrared (IR) spectroscopy in attenuated total reflection (ATR) mode was investigated as an alternate modality for assessment of the DM of HA hydrogels, including during the reaction progression...
August 10, 2018: Applied Spectroscopy
Alyssa B Zrimsek, Sergei V Bykov, Sanford A Asher
We demonstrate deep ultraviolet (UV) photoacoustic spectroscopy (PAS) of trace explosives using a sensitive microphone at meter standoff distances. We directly detect 10 µg/cm2 of pentaerythritol tetranitrate (PETN), 2,4,6-trinitrotoluene (TNT), and ammonium nitrate (AN) with 1 s accumulations from a 3 m standoff distance. Large PAS signals for standoff detection are achieved by exciting into the absorption bands of the explosives with a 213 nm laser. We also investigate the impact of the deep UV photochemistry of AN on the PAS signal strength and stability...
August 10, 2018: Applied Spectroscopy
Yang Xi, Yuee Li, Zhizhen Duan, Yang Lu
Noise and fluorescent background are two major problems for acquiring Raman spectra from samples, which blur Raman spectra and make Raman detection or imaging difficult. In this paper, a novel algorithm based on wavelet transform that contains denoising and baseline correction is presented to automatically extract Raman signals. For the denoising section, the improved conventional-scale correlation denoising method is proposed. The baseline correction section, which is performed after denoising, basically consists of five aspects: (1) detection of the peak position; (2) approximate second derivative calculation based on continuous wavelet transform is performed using the Haar wavelet function to find peaks and background areas; (3) the threshold is estimated from the peak intensive area for identification of peaks; (4) correction of endpoints, spectral peaks, and peak position; and (5) determine the endpoints of the peak after subtracting the background...
August 2, 2018: Applied Spectroscopy
H G Schulze, Shreyas Rangan, James M Piret, Michael Blades, Robin Turner
No abstract text is available yet for this article.
July 31, 2018: Applied Spectroscopy
Mei Liu, Ying Shi, Guang Ping Zhang, Yong Heng Zhang, Mei Mei Wu, Jun Feng Ren, Bao Yuan Man
No abstract text is available yet for this article.
July 31, 2018: Applied Spectroscopy
Irene Marivel Nolasco Perez, Amanda Teixeira Badaró, Sylvio Barbon, Ana Paula Ac Barbon, Marise Aparecida Rodrigues Pollonio, Douglas Fernandes Barbin
Identification of different chicken parts using portable equipment could provide useful information for the processing industry and also for authentication purposes. Traditionally, physical-chemical analysis could deal with this task, but some disadvantages arise such as time constraints and requirements of chemicals. Recently, near-infrared (NIR) spectroscopy and machine learning (ML) techniques have been widely used to obtain a rapid, noninvasive, and precise characterization of biological samples. This study aims at classifying chicken parts (breasts, thighs, and drumstick) using portable NIR equipment combined with ML algorithms...
July 31, 2018: Applied Spectroscopy
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