bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectroscopic Characterization of the SH2- and Active Site-Directed Peptide Sequences of a Bivalent Src Kinase Inhibitor
Authors: Desamero Ruel Z. B. , Kang Jeonghee , Dol Chrystel , Chinwong Justina , Walters Karim , Sivarajah Thulashie , Profit Adam A.
Published: October 2009

The spectral properties of the SH2 and active site-directed sequences of the bivalent Src kinase inhibitor Ac-EELL(F5)Phe-(GABA)3-pYEEIE-amide (1) have been determined. Ac-pYEEIE-amide (2) and Ac-EELL(F5)Phe-amide (3), as well as the amino acids phosphotyrosine (pTyr) and pentafluorophenylalanine (F5)Phe, have been characterized by electronic absorption, fluorescence, and vibrational spectroscopy. Specific and unique marker bands that originate from the phosphate group of pTyr and the fluorinated aromatic ring of (F5)Phe have been identified, with the latter showing some solvent dependence. Peptide 2 was found to have excitation and emission wavelengths emanating from pTyr at 268 and 295 nm, respectively, whereas peptide 3 displayed excitation and emission peaks attributable to (F5)Phe at 274 and 315 nm, respectively. Fourier transform infrared (FT-IR) analysis of the amino acid pTyr identified distinct marker bands at approximately 930, 1090, and 1330 cm−1 that could be attributed to the phosphate group. These markers were also observed in the IR spectrum of peptide 2. Likewise, peptide 3 displayed a characteristic C–F stretching mode at 961 cm−1 due to the presence of (F5)Phe, including two C–F reporting ring modes at 1509 and 1527 cm−1. Identifying and monitoring spectroscopic changes in these marker bands may afford a means to observe the molecular interactions that occur when peptides 1–3 bind to the Src kinase.
The Effect of Synthesis Temperature on the Formation of Hydrotalcites in Bayer Liquor: A Vibrational Spectroscopic Analysis
Authors: Palmer Sara J. , Frost Ray L.
Published: October 2009

The seawater neutralization process is currently used in the alumina industry to reduce the pH and dissolved metal concentrations in bauxite refinery residues through the precipitation of Mg, Al, and Ca hydroxide and carbonate minerals. This neutralization method is very similar to the co-precipitation method used to synthesize hydrotalcite (Mg6Al2(OH)16CO3-4H2O). This study looks at the effect of temperature on the type of precipitates that form from the seawater neutralization process of Bayer liquor. The Bayer precipitates have been characterized by a variety of techniques, including X-ray diffraction (XRD), Raman spectroscopy, and infrared spectroscopy. The mineralogical composition of Bayer precipitates largely includes hydrotalcite, hydromagnesite, and calcium carbonate species. Analysis with XRD determined that Bayer hydrotalcites that are synthesized at 55 °C have a larger interlayer distance, indicating that more anions are removed from Bayer liquor. Vibrational spectroscopic techniques have identified an increase in hydrogen bond strength for precipitates formed at 55 °C, suggesting the formation of a more stable Bayer hydrotalcite. Raman spectroscopy identified the intercalation of sulfate and carbonate anions into Bayer hydrotalcites using these synthesis conditions.
Fourth-Order Coherent Raman Spectroscopy of Liquid—Solid Interfaces: Near-Surface Phonons of TiO2 (110) in Liquids
Authors: Nomoto Tomonori , Onishi Hiroshi
Published: October 2009

The fourth-order coherent Raman response of a TiO2 (110) surface covered by HCl aqueous solution, neat octanol, acetic acid, or carbon tetrachloride layers is acquired. Four fourth-order optical responses were identified at 837–826, 452–448, 371–362, and 184–183 cm−1 and assigned to near-surface phonons of TiO2. A third-order response produced in the bulk liquid layer was superimposed on the fourth-order response, when coherent vibrations are efficiently excited in the layer.
Fuzzy Approach for Identifying Artistic Pigments with Raman Spectroscopy
Authors: Perez-Pueyo R. , Soneira M. J. , Castanys M. , Ruiz-Moreno S.
Published: October 2009

In this work, a fuzzy approach for automatically identifying artistic pigments from their Raman spectra is presented. The uncertainty introduced during the Raman spectrum measurement of pigments is considered in the design of the fuzzy system. The position of the Raman bands in the unknown spectrum can be subject to small displacements due to noise, misalignments in the calibration, etc. Fuzzy logic allows us to work with this uncertainty and to design a system based on the comparison between the Raman band positions in an unknown spectrum recorded from an artwork and the Raman band positions in spectra recorded from reference pigments gathered in databases. The fuzzy system provides the reference pigments whose Raman band positions match those of the unknown pigment analyzed and gives guidance to the decision-making process in the final identification.
The Infrared Spectra of Bacillus Bacteria Part I: Vegetative Bacillus versus Sporulated Cells and the Contributions of Phospholipids to Vegetative Infrared Spectra
Authors: Johnson Timothy J. , Su Yin-Fong , Valentine Nancy B. , Kreuzer-Martin Helen W. , Wahl Karen L. , Williams Stephen D. , Clowers Brian H. , Wunschel David S.
Published: October 2009

This paper highlights the distinctions between the infrared (IR) absorption spectra of vegetative versus sporulated Bacillus bacteria. It is observed that there are unique signatures clearly associated with either the sporulated or vegetative state and that vegetative cells (or cell debris) can contribute to the spore spectra. A distinct feature at ∼1739 cm−1 appears to be unique to vegetative cell spectra and can also be used as an indicator of vegetative cells or cell debris in the spore spectra. The data indicate that the band arises from a lipid-soluble species such as an ester or phospholipid carbonyl bond and are consistent with it being either phosphatidyl glycerol (PG) or phosphatidylethanolamine (PE), two major classes of phospholipids found in vegetative cells of Bacillus species. A companion work discusses bands associated with the sporulated state.
Design of a Laser-Induced Breakdown Spectroscopy System for On-Line Quality Analysis of Pulverized Coal in Power Plants
Authors: Yin Wangbao , Zhang Lei , Dong Lei , Ma Weiguang , Jia Suotang
Published: October 2009

It is vitally important for a power plant to determine the chemical composition of coal prior to combustion in order to obtain optimal boiler control. In this work, a fully software-controlled laser-induced breakdown spectroscopy (LIBS) system comprising a LIBS apparatus and sampling equipment has been designed for possible application to power plants for on-line quality analysis of pulverized coal. Special attention was given to the LIBS system, the data processing methods (especially the normalization with Bode Rule/DC Level) and the specific settings (the software-controlled triggering source, high-pressure gas cleaning device, sample-preparation module, sampling module, etc.), which gave the best direct measurement for C, H, Si, Na, Mg, Fe, Al, and Ti with measurement errors less than 10% for pulverized coal. Therefore, the apparatus is accurate enough to be applied to industries for on-line monitoring of pulverized coal. The method of proximate analysis was also introduced and the experimental error of Aad (Ash, ‘ad’ is an abbreviation for ‘air dried’) was shown in the range of 2.29 to 13.47%. The programmable logic controller (PLC) controlled on-line coal sampling equipment, which is designed based upon aerodynamics, and is capable of performing multipoint sampling and sample-preparation operation.
The Infrared Spectra of Bacillus Bacteria Part II: Sporulated Bacillus—The Effect of Vegetative Cells and Contributions of Calcium Dipicolinate Trihydrate, CaDP-3H2O
Authors: Johnson Timothy J. , Williams Stephen D. , Valentine Nancy B. , Su Yin-Fong
Published: October 2009

Our previous paper showed that certain infrared (IR) peaks, e.g., the peak at 1739 cm−1, are due to varying (trace) amounts of vegetative cells amongst the Bacillus spores and that these and other vegetative bands are associated with lipid-soluble compounds, likely an ester or phospholipid. This work investigates the infrared spectra of eight different sporulated Bacillus bacteria. For the endospores it is observed that peaks at 1441, 1277, and 1015 cm−1 along with a distinct quartet of peaks at 766, 725, 701, and 659 cm−1 are clearly associated with calcium dipicolinate trihydrate, CaDP·3H2O. It is emphasized that the spore peaks, especially the quartet, arise from the calcium dipicolinate trihydrate and not from dipicolinic acid or other dipicolinate hydrate salts. The CaDP-3H2O infrared peaks and the effects of hydration are studied using quantum chemistry in the PQS software package. The quartet is associated with many modes including contributions from the Ca2+ counterion and hydration waters including Ca–O–H bends, H2O–Ca–O torsions, and O–C–O bends. The 1441 and 1015 cm−1 modes are planar pyridine modes with the 1441 cm−1 mode primarily a ring C–N stretch and the 1015 cm−1 mode primarily a ring C–C stretch.
Fluorescence Intensity Calibration Using the Raman Scatter Peak of Water
Authors: Lawaetz A. J. , Stedmon C. A.
Published: October 2009

Fluorescence data of replicate samples obtained from different fluorescence spectrometers or by the same spectrometer but with different instrument settings can have great intensity differences. In order to compare such data an intensity calibration must be applied. Here we explain a simple calibration method for fluorescence intensity using only the integrated area of a water Raman peak. By applying this method to data from three different instruments, we show that it is possible to remove instrument-dependent intensity factors, and we present results on a unified scale of Raman units. The method presented is a rapid and simple approach suitable for routine measurements with no need for hazardous chemicals.
6Li Atom Percentage Determination by Atomic Absorption–Emission Spectrometry Using a Natural Lithium Hollow Cathode Lamp
Authors: Rehman Ejaz UR , Rehman Shakeel UR , Ahmed Shafaat
Published: October 2009

A simple method has been developed for the determination of 6Li atom % using combined atomic emission–absorption spectrometry employing a commonly available natural lithium hollow cathode lamp. Unlike in previous practice, there is no need for specially fabricated and high cost 6Li and 7Li monoisotopic lamps in this method. The method requires adjustment of total lithium contents of the sample, i.e., 6Li + 7Li, to 2 μg-mL−1 based upon atomic emission spectroscopy (AES) ( Caes) against a 2 μg-mL−1 natural lithium standard. The concentration of the sample was then analyzed by atomic absorption spectroscopy (AAS) measurements ( Caas). The difference between the concentration measured by AES and AAS, i.e., Caes — Caas, was calculated. The magnitude of the difference was found to be a function of 6Li fraction in the sample. A calibration curve was constructed by plotting 6Li atom % versus [( Caes — Caas)/ Caes] X 100. 6Li atom % of an unknown sample can be evaluated by putting its [( Caes — Caas)/ Caes] X 100 value in the calibration curve. The method is fast, convenient, and precise.
Demountable Liquid/Flow Cell for in vivo Infrared Microspectroscopy of Biological Specimens
Authors: Nasse M. J. , Ratti S. , Giordano M. , Hirschmugl C. J.
Published: October 2009

We have developed a liquid/flow cell/chamber allowing infrared measurements of living biological specimens with high spatial resolution under a controlled aqueous environment. This flow chamber features sub-micrometer thick diamond windows exhibiting low spherical and chromatic aberrations. Diamond has excellent transmission properties and minimal dispersion over the entire mid-infrared and visible spectral ranges. In contrast to current commercially available infrared liquid chambers, the flow chamber has a slim profile, which accommodates high resolution/magnification microscope objectives with small working distances, down to 0.6 mm above the chamber and 6 mm below the flow chamber. We have coupled a pump to the flow chamber to provide medium exchange. As an example, we present microspectroscopic infrared maps and spectra of the freshwater green alga Micrasterias sp. in the new flow chamber and compare them to maps obtained with a conventional liquid chamber. Pulse-amplitude-modulated fluorescence measurements on Micrasterias sp. cells inside the new flow chamber have been evaluated to demonstrate the viability of the algal cells.
Complete Theoretical Treatment of the Transmittance Ratio Ultraviolet/Visible Spectrophotometric Stray Radiant Energy Test Method
Authors: Fleming Paddy
Published: October 2009

This paper develops the theoretical basis behind the transmittance ratio test method for determining the relative stray radiant energy level in a double-beam dispersive spectrophotometer so as to allow for the non-transparency of a test solution towards the stray radiant energy for all sample beam-to-reference beam cuvette path length ratios. Non-transparency is defined as the transmittance of the reference beam solution, whose monochromatic absorbance is unity, towards stray radiant energy. The proposed method has the same concentration absorbing sample placed in the beams of the scanning spectrophotometer, the sample-beam cuvette being a known factor longer than the reference-beam cuvette. While scanning towards shorter wavelengths, an apparent differential absorbance Mielenz peak is recorded. An exact formula is derived in this paper relating the relative stray radiant energy level to the Mielenz peak absorbance, to the known cuvette path length ratio, to the observed monochromatic absorbance of the test sample at the Mielenz peak wavelength, and to the sample transmittance towards the stray radiant energy. Sample transmittance towards stray radiant energy cannot be determined experimentally. However, the derived formula only allows the other experimental quantities to tie in together for a single numerically calculated value for the sample-transmittance towards stray radiant energy. The formulae are tedious to derive and cumbersome to handle, but their application is facilitated greatly by a Microsoft Office Excel 2007 spreadsheet. The test method was applied to an ultraviolet–visible (UV/VIS) scanning spectrophotometer at nine wavelengths in the range 713 < γ (nm) >; 649 for a sample beam-to-reference beam cuvette path length ratio of 10 mm/5 mm and using blue food dye (E123) as the test material. Sample transparency to stray radiant energy fluctuated in wavelength between 0.819 and 0.948, while the relative stray radiant energy level fluctuated between 1.283 × 10−3 and 2.516 × 10−3. The investigation was repeated at 665.6 nm for all fifteen sample beam-to-reference beam cuvette path length ratios, which it was possible to establish using combinations of quartz-glass cuvettes with path lengths of 100, 50, 20, 10, 5, 2, and 1 mm. The sample transparency to stray radiant energy at 665.6 nm was 0.95 ± 0.5, while the relative stray radiant energy was (1.5 ± 0.33) × 10−3.
Thermally Induced Dissociation Nature of Pure 2-Pyrrolidinone via Near-Infrared Correlation Spectroscopy Analysis
Authors: Tang Hui , Sun Shengtong , Wu Peiyi
Published: October 2009

The temperature-dependent dissociation behavior of 2-pyrrolidinone in the pure liquid state was investigated via perturbation-correlation moving-window two-dimensional (PCMW2D) correlation spectroscopy and two-dimensional near-infrared (2D-NIR) correlation spectroscopy. Absorption bands in the region of 6900–6000 cm−1 assigned to the first overtones of stretching modes of NH groups provided detailed information about the dissociation process from 25 °C to 95 °C. On the basis of PCMW2D analysis, the sequence of dissociation events occurring during the temperature variation were elucidated in two temperature ranges (25–60 °C and 65–95 °C). Specific dissociation order of the hydrogen bond under temperature perturbation was disclosed by 2D-NIR correlation spectroscopy. As temperature increased, the dissociation of larger oligomers occurred firstly with the generation of smaller oligomers, which were then consumed later by the decomposition of hydrogen bonds. The dissociation of stable cyclic dimers occurred mainly at higher temperature through gradually weakened hydrogen-bonding of NH groups.
Differentiation of Healthy Brain Tissue and Tumors Using Surface-Enhanced Raman Scattering
Authors: Aydin Ömer , Altaş Murat , Kahraman Mehmet , Bayrak Ömer Faruk , Çulha Mustafa
Published: October 2009

Surface-enhanced Raman scattering (SERS) is a powerful technique for characterization of biological samples. SERS spectra from healthy brain tissue and tumors are obtained by sudden freezing of tissue in liquid nitrogen and crashing and mixing it with a concentrated silver colloidal suspension. The acquired spectra from tissues show significant spectral differences that can be used to identify whether it is from a healthy region or tumor. The most significant change on SERS spectra from the healthy/peripheral brain tissue to tumor is the increase of the ratio of the peaks at around 723 to 655 cm−1. In addition, the spectral changes indicate that the protein content in tumors increases compared to the peripheral/healthy tissue as observed with tumor invasion. The preliminary results show that SERS spectra can be used for a quick diagnosis due to the simplicity of the sample preparation and the speed of the spectral acquisition.
Light Sheet Direct Raman Imaging Technique for Observation of Mixing of Solvents
Authors: Oshima Yusuke , Furihata Chie , Sato Hidetoshi
Published: October 2009

The light sheet direct Raman (LSDR) imaging technique is used to obtain wide scope, simultaneous images of samples emitting Raman scattered light, without mapping their point-to-point Raman scattering intensities. A prototype system consisting of a background-free electronically tuned Ti:sapphire laser (BF-ETL), band-pass (BP) filters, and a charge-coupled device (CCD) detector is developed in the present study. The LS excitation method enables us to obtain a wide field of Raman view. The BF-ETL allows us to obtain direct Raman images with multiple Raman bands without the need for rearranging the optical settings. The system is used to observe the mixing of pure solvents: carbon tetrachloride (CCl4) and chloroform (CHCl3), and ethylene glycol (EG) and polyethylene glycol (PEG). LSDR images are successfully obtained within an exposure time of 0.5 s. EG and PEG, whose Raman spectra appear similar, can be distinguished clearly in the images, suggesting that the system has high spectral resolution.
Effects of Added Minerals (Calcium, Phosphate, and Citrate) on the Molecular Structure of Skim Milk as Investigated by Mid-Infrared and Synchronous Fluorescence Spectroscopies Coupled with Chemometrics
Authors: Boubellouta Tahar , Galtier Virginie , Dufour Éric
Published: October 2009

Minerals play an important role in the structure and stability of casein micelles: minerals and caseins in milk are in dynamic equilibrium. Front-face synchronous fluorescence and mid-infrared spectra in combination with multivariate statistical analysis have been used to investigate, at a molecular level, the effects of added minerals (calcium, phosphate, or citrate) on mineral equilibria and casein micelle structure. Synchronous fluorescence spectra were recorded in the 250–500 nm excitation wavelength range using an offset of 80 nm between the excitation and emission monochromators for skim-milk samples fortified with 0, 3, 6, and 9 mM of calcium, phosphate, or citrate at 30 °C and 4 °C. Regarding mid-infrared spectroscopy, the region located between 1700–1500 cm−1, corresponding to the amide I and II bands, and the 1500–900 cm−1 region, called the fingerprint region, were considered for the characterization of the fortified skim-milk samples at the two considered temperatures. Principal component analysis (PCA) was applied to the collections of fluorescence and infrared spectral data of the two systems to optimize their description. The results show that the phenomena induced by the addition of phosphate were different from the ones observed following the addition of calcium or citrate, a calcium-chelating agent. Finally, common components and specific weights analysis was applied to infrared spectra and fluorescence data collected on fortified skim-milk samples. This analysis enabled the relationship between the different data tables to be established.
Gold Nanoparticle Based Surface-Enhanced Raman Scattering Spectroscopy of Cancerous and Normal Nasopharyngeal Tissues under Near-Infrared Laser Excitation
Authors: Feng Shangyuan , Lin Juqiang , Cheng Min , Li Yong-Zeng , Chen Guannan , Huang Zufang , Yu Yun , Chen Rong , Zeng Haishan
Published: October 2009

The capabilities of using gold nanoparticle based near-infrared surface-enhanced Raman scattering (SERS) to obtain biochemical information with high spatial resolution from human nasopharyngeal tissue were presented in this paper. The gold nanoparticles used have a mean diameter of 43 nm with a standard deviation of 6 nm. The SERS bands of nasopharyngeal tissue were assigned to known molecular vibrations of nucleic acids, amino acids, proteins, and metabolites. We also observed the blinking phenomenon at the tissue level when measuring the nasopharyngeal tissue SERS spectra, most frequently in signal intensity but also occasionally in peak positions. This phenomenon is excitation light intensity dependent. This work demonstrated great potential for using SERS imaging for distinguishing cancerous and normal nasopharyngeal tissues on frozen sections without using any dye labeling or other chemical species as functionalized binding sites.
The Use of a Combination of Atom and Ion Lines as Internal Standards in General Spectrochemical Analysis
Authors: Tymchuk P. , Russell D. S. , Berman S. S.
Published: October 2009

This study showed that using the atom, ion, and a combination of atom and ion lines of only two elements as internal standards, it was possible to obtain very good results on a wide variety of elements in different matrices The samples were mixed into a rubidium chloride-graphite medium and burned to completion in a dc arc using a Stallwood jet. Analysis of the results, carried out on twelve elements in six matrices, showed that in 55 out of 70 cases an accuracy of better than 15% was attained (29 of these were within 5%). Both major and minor components were determined on the same spectrogram. Elements included Na, Al, Ba, Ca, Fe, Mg, Mn, Pb, Si, Sn, Zn, and Zr with indium and lutecium used as the internal standards.
The Infrared Spectra of Acidic, Neutral, and Basic Aqueous Solutions of Glycine, N-Methylglycine, N,N-Dimethylglycine, and N,N,N-Trimethylglycine
Authors: Kirschenbaum Donald M.
Published: October 2009

The infrared spectra of aqueous solutions of glycine, N-methylglycine (sarcosine), N,N-dimethylglycine, and N,N,N-trimethylglycine (betaine) in different states of ionization are reported. The spectra of the dipolar forms of the first three compounds are shown to consist of bands represented in the spectra of both the positively and negatively charged forms, together with certain bands peculiar only to the dipolar form. In the spectrum of dipolar betaine, which exhibits no negatively charged structure, certain of the bands are also demonstrable in the spectrum of the positively charged form. Aqueous solutions of the hydrochlorides of the four compounds exhibit a strong band at 7.94 or at 8 00 microns, which disappears and is replaced by a band appearing at 7.5 to 7.6 microns when aqueous solutions of the sodium salts are examined. Methyl substitution on the nitrogen is revealed by a band between 6 7 and 6 8 microns, which is absent in the unsubstituted compound, glycine.
“Peek-a-Boo” Data Retrieval in Infrared Spectroscopy
Authors: Schlichter Naomi E. , Wallace Ellen
Published: October 2009

As the number of cards in the Wyandotte-ASTM system of data retrieval increase, the time to sort for an answer increases accordingly Simpler and more rapid methods of storage and retrieval are desirable This paper describes our limited, but promising, experience with an inverted “peek-a-boo” system as it applies to the particular needs of our laboratory. In this system each card represents a characteristic, and each compound has a location in the Cartesian grid of the card Holes are drilled at the location of the compound having the characteristic described by the card. A complete deck requires 250 cards and can retain information for 10,000 compounds. Searching is based on optical coincidence. Advantages of the system are simplicity, rapidity of output, ease of adding characteristics, and relatively inexpensive equipment.
The Far Infrared Spectra of Monosubstituted Pyridines
Authors: Isaac Raymond , Bentley Freeman F. , Sternglanz Helene , Coburn W. C. , Stephenson C. V. , Wilcox W. S.
Published: October 2009

Infrared spectra in the cesium bromide region are presented for 43 monosubstituted pyridines. Two- and 3-substituted pyridines are characterized in this region by two relatively intense bands near 600 and 400 cm−1. No strong characteristic bands are found for 4-substituted pyridines. The vapor-phase contours of the far infrared bands of 2-fluoro- and 2-chloropyridine indicate that the 600 and 400 cm−1 bands arise, respectively, from an in-plane and an out-of-plane vibration. The pyridine spectra are compared with the spectra of some substituted benzenes
X-Ray Fluorescence Analysis of the Light Elements in Rocks and Minerals
Authors: Rose Harry J. , Adler Isidore , Flanagan Francis J.
Published: October 2009

Recent advances in the x-ray fluorescence analysis of the light elements offer the advantage of speed and an accuracy approaching that of wet chemical procedures In addition to Fe, Mn, Ti, Ca, and K, the elements P, Si, Al, and Mg, previously considered too light to be determined quantitatively, can now be included in the scheme of analysis X-ray fluorescence analysis of these light elements is primarily confined to layers close to the surface, with the attendant problems of particle size, mineralogic history, and absorption differences owing to compositional variation among samples Fusion of the sample with a suitable flux eliminates problems of particle size and mineralogic differences Simple fusion, however, does not eliminate absorption differences due to variation in matrix By introducing into the fusion melt a strong absorber (La2O3) for the light elements, the variation in concentration of absorbing elements in the unknown sample will not materially affect the overall absorption of the fused mass for the elements being determined This permits the use of a single set of standards regardless of the rock type to be analyzed

The x-ray fluorescence method has been applied to the analysis of a wide variety of rock types such as granite, diabase, dunite, limestone, dolomite, and phosphate rock, with results that compare favorably with chemical values
Quantitative Determination of Carbon in Solid Hydrocarbons Using the Intensity Ratio of Incoherent to Coherent Scattering of X-Rays
Authors: Toussaint C. J. , Vos G.
Published: October 2009

A method is presented for the determination of carbon in solid hydrocarbons using the intensity ratio of incoherent to coherent scattering of x-rays. The method is very rapid with precision at the 95% confidence level of about ±0.3%. The minimum sample weight necessary is 0 2 g. Analysis of samples by the x-ray method shows good agreement with values obtained by microcombustion. Finally a general comparison between different methods for carbon determination in solid hydrocarbons is discussed.
The Infrared Spectra of Some Acenaphthenes, Biphenyls, Fluorenes, Indans, Naphthalenes, and Tetralins
Authors: Hume Janis M. , Jenkins Gilbert I.
Published: October 2009

A systematic study has been made of all of the available infrared spectra of acenaphthenes, biphenyls, fluorenes, indans, naphthalenes and tetralins. Bar charts giving the wavelengths between 8 and 1 5 microns at which the bands occur in the spectrum of each compound and also their approximate intensities have been prepared for each of the six groups of compounds and spectral/structural correlations derived from them The correlations together with those already established for alkylbenzenes should be useful in the identification of aromatic hydrocarbons in petroleum fractions and other hydrocarbon mixtures

Some acenaphthenes, fluorenes, and naphthalenes have also been examined in the 15 to 22 microns region.
Mechanisms of Interactions of Alkali and Alkaline Earth Elements in Flame Photometry
Authors: Johnson Russell W. , Schrenk W. G.
Published: October 2009

Cationic interactions in flame photometry were investigated to study some of the factors that cause enhancements of spectral lines. Interactions of the alkali and alkaline earth metals in an oxygen-acetylene flame have indicated that several mechanisms may be responsible for enhancement Where conditions are proper, enhancements of emissions of cations may be a combination of at least three factors a) the effect of electron concentration from an easily ionized extraneous element on the ground state population of the test element, b) the effect of transfer of energy by radiation and c) the effect of transfer of energy due to collisions with excited atoms

The effect of the electron concentration on the suppression of the ionization of the test element was the predominant mechanism by which enhancement occurred in most systems studied. However, in the study of the effect of potassium on rubidium direct evidence was obtained of excitation by transfer of radiant energy Indirect evidence of enhancement due to transfer of energy by collision also was observed in the same system.
Determination of Empirical Formulae by Precision Mass Measurements
Authors: van Katwijk J.
Published: October 2009

A method is presented for the determination of empirical formulae consistent with precision mass data measured with a high-resolution mass spectrometer. It involves some simple calculations and a table, and eliminates tedious trial and error procedures Factors influencing the number of possible formulae obtained for a measured mass value arc discussed
Moisture-Induced Transformations of α- and β-D-Glucoses as Revealed by Infrared Spectroscopy
Authors: Segal Leon
Published: October 2009

Spectral data are presented showing that the β form of glucose can be changed to the α form while in the solid phase, but this is not reversible. The existence of β-D-gIucose hydrate is postulated. Anomer transformation occurs only with the hydrated sugar Rigorous drying of infrared-quality KBr was found unnecessary for use with the sugars
Vibrational Spectra of Benzene Derivatives. II. Frequency Assignments in the CsBr Region
Authors: Jakobsen R. J. , Bentley F. F.
Published: October 2009

Frequency assignments in the CsBr spectral region (65 0 to 28 5 cm−1) have been made from the spectra of 279 benzene derivatives The Raman spectra of 119 of these compounds were also used as aids in making the assignments. The assigned frequencies include several benzene-like ring-deformations and some vibrations that are either internal vibrations of the substituent group or involve the ring-substituent bond. A variation in frequency with symmetry or substitution type (ortho, meta, para, etc.) was found for the ring-deformations. Within a given substitution type certain of the ring-deformation vibrations were found to be sensitive to substituent effects The assigned frequencies involving the substituent group can be classified as characteristic frequencies of benzene compounds with a particular substituent
A Versatile Electronic Computer for Photoelectric Spectrochemical Analysis
Authors: Weekley R. E. , Norris J. A.
Published: October 2009

An electronic system has been designed with which it is possible to make dynamic background corrections by modifying existing commercial direct-reading equipment. The resulting linear curves make practical the use of simple electronic analog computation equipment to automatically calculate analytical values The design and use of a versatile computer to carry out this function is described Its application to the spectrochemical analysis of clamshells for Ba, Mn, Na, and Sr is presented.
Study of Thermal Decomposition Products of Silica-Filled Polytetrafluoroethylene with an Infrared Pyrolysis Cell
Authors: Brash Mark P. , Light Truman S.
Published: October 2009

An infrared pyrolysis cell has been developed which permits thermal decomposition of microsamples in the beam of an infrared spectrophotometer. Organic and inorganic materials may be degraded at controlled temperatures up to 1100°C in oxidizing, inert, or vacuum atmospheres The system silica-polytetrafluoroethylene (PTFE, Teflon) was studied in the temperature range 500 to 600°C in air and in helium. When heated in air, mixtures containing up to 23 per cent silica were totally volatilized, but in an inert atmosphere only the PTFE is volatilized without loss of significant quantity of silica. The principal species observed following the air pyrolysis of silica-PTFE composite were S1F4, COF2, and CO2; the same material pyrolised in helium resulted in the identical products as unfilled PTFE, namely, C2F, C3F and C4F8 The probable equation for the interaction between PTFE and silica in air is (– C2F4 –)n + S1O2 + 2O2 → 2COF2 + S1F4 + 2CO2 + C2F4 + C2V4 recombination products
Infrared and Raman Spectra of Some Pentamethyldisilanyl Compounds
Authors: Urenovitch Joseph V. , MacDiarmid Alan G. , Nixon Eugene R.
Published: October 2009

Infrared and Raman spectra are reported for a number of pentamethyldisilanyl compounds in the liquid state. These include the chloride, cyanide, isocyanate, ether, and amine derivatives. The assignment of the vibrational bands is discussed, particularly for those modes involving the heavy atom skeletons.
Spectroscopic Studies of Substituted Benzalanilines
Authors: Margerum J. David , Sousa John A.
Published: October 2009

Ultraviolet and visible spectra are reported for 28 N-benzylidineanilines with their molar absorptivities given in absolute ethanol, and in isooctane when feasible. Infrared studies in the 2–15 micron region are reported for these compounds and also for three newly synthesized N-d-benzylidineamhnes. With the aid of these deuterated benzalanilines, infrared assignments are given for the frequencies characteristic of the center —CH=N-azomethine group. The ultraviolet and infrared spectra are compared in relation to the reported basicity of their azomethine groups.
Some Factors Affecting the Precision of Solution Analysis by the Rotrode Technique
Authors: Eardley R. P. , Clarke H. S.
Published: October 2009

Some of the factors affecting the precision of analysis of aqueous solutions by the rotrodc technique are described. These include speed of revolution, depth of solution, electrode material, pre-spark time, and variations in integration time which is automatically controlled by the internal standard intensity. Suggestions are made to minimize these effects to give the best precision
Preclassification System for the Wyandotte-ASTM Punched Cards, Indexing Spectral Absorption Data
Authors: Leysen R. , Van Rysselberge J.
Published: October 2009

Once that the number of Wyandotte-ASTM punched cards indexing spectral absorption data exceeded several thousand, it was necessary to use a more rapid method in order to obtain a reasonable speed of retrieval. A preclassification of the total deck is described which needs no other special equipment than a card sorting machine. With this method 2,836 cards must be handled in the most unfavorable case instead of the 42,000 representing the authors' collection.
Instrumentation in Industrial Hygiene
Authors: Keenan Robert G.
Published: October 2009

A discussion of the many types of samples encountered in industrial hygiene studies, the techniques and instruments used for their collection, the methods used for their preliminary chemical treatment, and the spectrographic instrumentation and techniques employed for the quantitative determination of their trace metallic constituents is presented. In this paper emphasis has been placed on the need to use sharp, clean separation procedures, along with appropriate instrumentation, to meet the analytical objectives in this field, i.e., highly sensitive, precise determinations of minute amounts of chemical substances. The high utility of the emission spectrograph for the analysis of metallic elements has been illustrated with typical examples of analytical applications made in the author's laboratory.
Use of Stabilized Plasma Arc Excitation in Determining the Element Boron in Gasoline
Authors: Vigler M. S. , Failoni J. K.
Published: October 2009

This report describes the use of a stabilized plasma arc source in the quantitative spectrographs determination of boron in gasoline. The advantage is that the plasma arc requires no preliminary sample preparation other than addition of nickel hexoate internal standard in ethyl alcohol buffer solution. The National Bureau of Standards # 1063 menthyl borate may be used for preparing calibration curves. The method is applicable to the determination of boron in the range of 0.0001 to 0.0010 per cent. The standard deviation is 0.000055 per cent; the coefficient of variation is 8.1 per cent.
Infrared Study of Some Oxalamidines
Authors: Macovei Vasile P. , Robinson D. W.
Published: October 2009

Infrared spectra of various aromatic-substituted oxalamidines have been obtained. The behavior of the vibrational bands originating in the amidine groupings as a function of solution concentration is interpreted as indicating the presence of persistent intramolecular hydrogen bonding.
Mass Spectrometric Observation of Polymers of Carbon Dioxide in a Molecular Beam System
Authors: Cuthbert J. , Preece E. R. , Turnbull A. H.
Published: October 2009

The operation of a mass spectrometer equipped with a molecular beam gas sampling system is described. Polymeric ions, (CO2)n+ where n varies from two to twelve, are observed when sampling CO2 at 1 to 6.5 atm; similar polymers are found in SO2 and N2O. A possible explanation is advanced in terms of isentropic expansion in the sampling process and subsequent condensation.
An Element-Specific, Dual-Channel, Flame Infrared Emission, Gas Chromatography Detector for Chlorinated and Fluorinated Hydrocarbons
Authors: Ravishankar S. , Tilotta David C. , Busch Kenneth W. , Busch Marianna A.
Published: October 2009

A flame infrared emission (FIRE) gas chromatography (GC) detector for organofluorine and organochlorine compounds has been developed and evaluated. The element-specific GC-FIRE detector makes use of a beamsplitter to divide the source radiation into two optical paths. The divided radiation passes through appropriate notch filters to isolate the background and analyte emission, which are each monitored by separate lead selenide detectors that form part of a Wheatstone bridge network. The output from the Wheatstone bridge is fed into the differential mode (A-B) input of a lock-in amplifier (LIA). In the chlorine mode of operation, a 3.7- μm optical notch filter is used in the analytical channel to isolate a portion of the HCl emission that results when organochlorine compounds are combusted in the hydrogen/air flame. In the fluorine mode of operation, a 2.35- μm optical notch filter in combination with a 2.55- μm short-pass filter is used to isolate a portion of the HF emission that results when organofluorine compounds are combusted. With the use of the dual-channel system, selectivity ratios of at least 760 (F) and 100 (Cl) were obtained, respresenting improvements by factors of about 104 (F) and 30 (Cl) in comparison with results from the single-channel mode of operation. With the use of Freon-113® (C2Cl3F3) as a representative analyte, detection limits in both the chlorine- and fluorine-selective modes were 200 ng s−1, representing improvements by factors of about 9.5 (F) and 4.5 (Cl), in comparison with results from the single-channel mode of operation.
Comparison of Different Excitation Sources and Normalization Techniques in Laser-Ablation AES Using a Photodiode-Based Spectrometer
Authors: Richner P. , Borer M. W. , Brushwyler K. R. , Hieftje G. M.
Published: October 2009

A new technique is evaluated for normalizing laser power fluctuations in laser-ablation atomic spectrometry. The technique involves measuring the light loss caused by scattering from the ablated material as it flows through a specially designed cell. The resulting measured optical density can be used to correct for variations in the amount of sample that has been ablated. This new approach is compared to the use of a matrix element as an internal standard. Three different excitation sources for AES (Ar-ICP, Ar-MIP, and He-MIP) were combined with laser ablation and evaluated with the new normalization approach. Although the overall performance is best for the Ar-ICP combination, the MIPs have some desirable characteristics (i.e., low background radiation) which in some cases lead to better results. The spectra were collected with a photodiode-based spectrometer that is designed for simultaneous multichannel detection and is therefore especially well suited to measurement and background correction of signals produced during transient sampling such as with laser ablation. The ability of such a spectrometer to deal with complex samples such as cast iron is discussed.
Temperature Dependence of the Resonant and Nonresonant CARS Signals
Authors: Kukk P. , Lohmus A. , Korppi-Tommola J.
Published: October 2009

We have studied the temperature dependence of resonant and nonresonant CARS signals in benzene, in toluene, and in n-alcohol mixtures. A cryostat was constructed to allow cooling of flowing liquids. In nonpolar solvents, the nonresonant background signal does not seem to depend on temperature, while in n-alcohol mixtures an enhancement of the nonlinear CARS signal is observed. Lowering temperature in these solutions enhances detectability of weak impurity lines in the resonant CARS spectrum.
Determination of Physical Properties of Reaction-Injection-Molded Polyurethanes by NIR-FT-Raman Spectroscopy
Authors: Miller Charles E. , Archibald D. D. , Myrick M. L. , Angel S. M.
Published: October 2009

Near-infrared-FT-Raman spectroscopy can be used to nondestructively analyze reaction-injection-molded (RIM) Polyurethane elastomers. Unlike conventional 514.5-nm excitation, the 1064.1-nm excitation of NIR-FT-Raman spectroscopy does not produce significant sample fluorescence. In this work, the ability of NIR-FT-Raman spectroscopy to determine flex moduli of Polyurethane elastomers is evaluated. Comparisons are made between NIR-FT-Raman, dispersive Raman with 514.5-nm and 752-nm excitation, and NIR diffuse reflectance spectroscopy for Polyurethane analysis.
Development of an Interferometer with Interchangeable Polarization and Amplitude Divisions for the 1000-10 cm−1 Region
Authors: Weibel S. , Polavarapu P. L.
Published: October 2009

An interferometer for spectroscopic measurements from approximately 1000 cm−1 into the far-infrared region employing a single beamsplitter is developed. It consists of a free-standing wire grid beamsplitter and two roof-top mirrors. When the beamsplitter grids are oriented at 45° to the roof axes of the mirrors and the input light is polarized at 45° to the beamsplitter grids, the interferometer functions as a Martin-Puplett type with polarization division from approximately 600 cm−1 to about 10 cm−1. Alternately, when the beamsplitter grids are parallel to the roof axes of the mirrors, and the input light is unpolarized the interferometer functions as a Michelson type with amplitude division, for spectral measurements in the 1000-100 cm−1 region.
FT-Raman Investigations of Forest Products
Authors: Kenton R. C. , Rubinovitz R. L.
Published: October 2009

FT-Raman spectroscopy has been used to analyze several forest product materials. Spectra of balsa, oak, pine, and redwood have been obtained. These data can be used to differentiate between hard and soft woods by examination of the ratio of the intensities of those bands attributable to cellulose and lignin as well as by the presence (or absence) of a band near the 1269-cm−1 Raman shift that can be assigned to rosin. Analysis of coatings on paper via FT-Raman methods has also been accomplished. Results from measurements of red ink deposited upon filter paper and from a commercial paper sample are presented. The significance of these findings will be discussed.
Infrared Reflection-Absorption Spectroscopy of the Electrode/Electrolyte Solution Interface: Optical Considerations
Authors: Faguy Peter W. , Fawcett W. Ronald
Published: October 2009

Calculations based on the classical Fresnel equations have been carried out to investigate the effect of various experimental parameters on infrared spectra obtained for molecules adsorbed at the electrode/solution interface. The effects considered include the nature of window material, the variation in the angle of incidence, the incident beam diameter, the instrument focus, and the presence of an absorbing bulk electrolyte solution. It is shown that, under certain circumstances, the resultant spectra are enhanced with respect to those obtained in the absence of an IR window and bulk adsorbing phase. The significance of the present results with respect to practical experiments is discussed.
Pyridine Used as a Probe for Internal Brønsted Acid Sites in Pyrochlore Antimony (V) Oxide: An Infrared Spectroscopy Study
Authors: Benvenutti Edilson V. , Gushikem Yoshitaka , Davanzo Celso U.
Published: October 2009

Brønsted acid sites inside the 0.3-nm-diameter cavities of pyrochlore antimony (V) oxide were detected with the use of pyridine as a probe molecule, and following the appearance of pyridinium ions by infrared spectroscopy (8 a and 19 b modes). The pyridine molecule is larger than the cavities' windows and can only bind acid sites when the oxide is strongly hydrated. This observation indicates that the protons are free to migrate to the surface.
Raman Microprobe with Holographic Beamsplitter for Low-Frequency Operation
Authors: Pallister David M. , Liu Kei-Lee , Govil Anurag , Morris Michael D. , Owen Harry , Harrison Timothy R.
Published: October 2009

A Raman microprobe with a holographic beamsplitter is described. The beamsplitter is shown to have 90% laser insertion efficiency and high Raman transmission efficiency on both the Stokes and anti-Stokes side. Useful spectra are obtainable as close as ±60 cm−1 from the exciting line using 4 mW power.
Simple Method to Measure the Coherence Time of a Mode-Locked Laser
Authors: Iwata Tetsuo , Hieftje Gary M.
Published: October 2009

A simple method is described to measure the coherence time of a mode-locked pulse train. The temporal coherence function is obtained from an interference pattern produced by crossing the two laser pulses at a linear photodiode array (PDA) detector. Two wave-fronts generated from the same or from successive pulses are tilted with respect to each other and intersect the PDA at a small angle; the “visibility” of the resulting fringe pattern is then plotted as a function of the temporal offset between the interfering pulses. The coherence time of a mode-locked Ar+ laser (225 ps) and that of a synchronously pumped mode-locked dye laser (5.0 ps) have been measured.
Microreflectance Infrared Study of Bis(Ethylenedithio)-Tetrathiafulvalene (BEDT-TTF or ET) Salts
Authors: Ferraro John R. , Wang H. Hau , Whangbo Myung-Hwan , Stout Phil
Published: October 2009

For several β- and κ-phase salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or simply ET) and its deuterium analog d8-ET, microreflectance infrared spectra were obtained by employing polarized and unpolarized light, and their vibronic regions were examined. These salts exhibit a strong vibronic absorption under polarized light. The vibronic absorption of the β-phase salts has a much stronger polarization-dependency than that found for the κ-phase salts. For the β-phase salts, the optimum vibronic absorption occurs when the polarized light vector is parallel to their donor-molecule stacking direction. Among the ET salts without structural disorder, the highest C-C-H bending frequency for the superconductors is lower than ∼1320 cm−1 while that for the non-superconductors is higher than ∼1320 cm−1.