bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulsed Laser Excited Photothermal Lens Spectrometry of CdSxSe1—x Doped Silica Glasses
Authors: Joshi Prakash R. , Dada Oluwatosin O. , Bialkowski Stephen E.
Published: October 2009

Experimental results for photothermal lens measurements are compared to finite elemental analysis models for commercial colored glass filters. Finite elemental analysis software is used to model the photothermal effect by simulating the coupling of heat both within the sample and out to the surroundings. Modeling shows that heat transfer between the glass surface and the air coupling fluid has a significant effect on the predicted time-dependent photothermal lens signals. For comparison with experimental signals, a simple equation based on the finite element analysis result is proposed for accounting for the variance of experimental data where this type of heat coupling situation occurs. The colored glass filters are found to have positive thermo-optical coefficients. The net positive dn/dT of CdSxSe1–x doped glass filters is considered to be the consequence of counteracting factors: optical nonlinearity, stress-induced birefringence, and the structural network of glass. Finite element analysis modeling results are also used to correlate experimental measurements of different sample geometries. In particular, the glass samples are compared to ethanol solutions of iron (II) dicylopentadiene in a sample cuvette even though heat transfer is different for these two samples.
Raman Microscopic Applications in the Biopharmaceutical Industry: In situ Identification of Foreign Particulates inside Glass Containers with Aqueous Formulated Solutions
Authors: Cao Xiaolin , Wen Zai-Qing , Vance Aylin , Torraca Gianpiero
Published: October 2009

Particle identification is an important analytical procedure for quality control and assurance in the biopharmaceutical industry. Rapid and reliable identification of micro-particles helps in evaluating the nature of particle contamination and its consequences on the product quality regulated by internal and external standards. Raman microscopy is one of the microspectroscopic techniques that can be used to identify micro-particles with the advantage of in situ detection. In this paper we demonstrate that a visible laser Raman microscope was particularly useful to identify micro-particles that were inside glass containers such as glass syringes, vials, and test tubes, which are commonly used as containers for aqueous formulated drugs. The examples include the identifications of a droplet-like particle inside a pre-filled glass syringe, a fibrous particle inside a glass test tube, and a white particle inside a glass vial; all of these examples usually demand challenging or time-consuming sample manipulation for other techniques. The Raman microscopic technique was shown to be able to solve these challenging micro-particle identifications due to its ability to carry out detection in situ. Particularly in the example of micro-droplet identification, the Raman microscopic technique was the only choice for a fast and successful particle detection. For all three identifications, Raman in situ detection has significantly accelerated particle analysis and avoided potential sample secondary contamination or losses owing to none or minimal sample manipulation.
Attenuated Total Internal Reflection Fourier Transform Infrared Spectroscopy: A Quantitative Approach for Kidney Stone Analysis
Authors: Gulley-Stahl Heather J. , Haas Jennifer A. , Schmidt Katherine A. , Evan Andrew P. , Sommer André J.
Published: October 2009

The impact of kidney stone disease is significant worldwide, yet methods for quantifying stone components remain limited. A new approach requiring minimal sample preparation for the quantitative analysis of kidney stone components has been investigated utilizing attenuated total internal reflection Fourier transform infrared spectroscopy (ATR-FT-IR). Calcium oxalate monohydrate (COM) and hydroxylapatite (HAP), two of the most common constituents of urinary stones, were used for quantitative analysis. Calibration curves were constructed using integrated band intensities of four infrared absorptions versus concentration (weight %). The correlation coefficients of the calibration curves range from 0.997 to 0.93. The limits of detection range from 0.07 ± 0.02% COM/HAP where COM is the analyte and HAP is the matrix, to 0.26 ± 0.07% HAP/COM where HAP is the analyte and COM is the matrix. This study shows that linear calibration curves can be generated for the quantitative analysis of stone mixtures provided the system is well understood especially with respect to particle size.
A Similarity Measure for Two-Dimensional Fluorescent Spectra
Authors: Bai Wenliang , Ren Ming , Hopke Philip K. , Gan Feng
Published: October 2009

A similarity measure was developed that can differentiate between two-dimensional fluorescent spectra based on their similarities and differences. The two-dimensional fluorescent spectra are digitalized into matrices. The difference between the two spectra is defined by a difference matrix, whose elements contain the difference of one two-dimensional fluorescent spectrum minus the other. The similarity measure is transformed into hypothesis tests of the similarity and difference between the two spectra. The scalar mean of the difference matrix is used as the statistical variable for the hypothesis test. The Bayesian prior odds ratio was estimated from multiple spectra of the same reference sample. A threshold for the hypothesis test that the spectra are different is proposed. The posterior odds ratio was used to quantify the similarity measure of the two spectra. Two-dimensional fluorescent spectra of Changyu red wine samples were used to demonstrate this method. The results show that this new method can detect differences between the spectra.
Near-Infrared Spectroscopic Investigation of the Hydrothermal Degradation Mechanism of Wood as an Analogue of Archaeological Wood. Part II: Hardwood
Authors: Inagaki Tetsuya , Mitsui Katsuya , Tsuchikawa Satoru
Published: October 2009

Near-infrared (NIR) spectroscopy and chemometrics were applied to analyze the degradation mechanism of hardwood following hydrothermal treatment. NIR spectra, chemical composition, oven-dried density, equilibrium moisture content, compressive Young's modulus parallel to grain, and cellulose crystallinity of artificially degraded beech as an analogue of archaeological wood were systematically measured. Partial least squares (PLS) regression analysis was employed to predict compressive Young's modulus using NIR spectra and various properties as independent variables. Results are also compared with previous data obtained from similar treatment of softwood (Hinoki cypress). The increase in cellulose crystallinity of hardwood during the initial stage of hydrothermal treatment (up to 5 hours) was correlated with an improvement in the mechanical properties of wood. Young's modulus for both hardwood and softwood showed a gradual decrease over five hours of hydrothermal treatment, which is proposed to be due to the degradation of polysaccharide.
Reconstruction Method and Optimal Design of an Interferometric Spectrometer
Authors: Parrein Pascale , Landragin-Frassati Anne , Dinten Jean-Marc
Published: October 2009

In this paper, we present a method to estimate the power spectral distribution of a source from input data acquired by an interferometric-based spectrometer. Our spectrometer shows distortions in the fringe pattern and a lack of data, making it impossible to apply the Fourier transform approach, which is the gold standard as a spectral recovery method for interferometric spectrometers. We combined linear inverse problem solving and iterative methods instead, considering that each detector of the spectrometer has a specific and known spectral response. Iterative methods are used to overcome problems caused by lack of input data. We show that a good spectral estimation of relatively simple spectra having a resolution of 400 points is typically achieved using fewer than 10 detectors with such a method. Since the quality of spectral restitution with such an approach relies both on signal processing and an optimal selection of the detector's spectral responses, the paper also shows that some sets of spectral responses selected for the detection and consequently a spectral repartition of the detectors are more successful than others in the spectral recovery process. We chose the condition number of the inversion matrix as an optimization criterion and evaluated how this criterion can be used within this framework. We found that maximizing it achieves better spectral restitution, within a range where noise remains low.
The Role and Selection of the Filter Function in Fourier Self-Deconvolution Revisited
Authors: Lórenz-Fonfría Víctor A. , Padrós Esteve
Published: October 2009

Overlapped bands often appear in applications of infrared spectroscopy, for instance in the analysis of the amide I band of proteins. Fourier self-deconvolution (FSD) is a popular band-narrowing mathematical method, allowing for the resolution of overlapped bands. The filter function used in FSD plays a significant role in the factor by which the deconvolved bands are actually narrowed (the effective narrowing), as well as in the final signal-to-noise degradation induced by FSD. Moreover, the filter function determines, to a good extent, the band-shape of the deconvolved bands. For instance, the intensity of the harmful side-lobule oscillations that appear in over-deconvolution depends importantly on the filter function used. In the present paper we characterized the resulting band shape, effective narrowing, and signal-to-noise degradation in infra-, self-, and over-deconvolution conditions for several filter functions: Triangle, Bessel, Hanning, Gaussian, Sinc2, and Triangle2. We also introduced and characterized new filters based on the modification of the Blackmann filter. Our conclusion is that the Bessel filter (in infra-, self-, and mild over-deconvolution), the newly introduced BL3 filter (in self- and mild/moderate over-deconvolution), and the Gaussian filter (in moderate/strong over-deconvolution) are the most suitable filter functions to be used in FSD.
Calibration Maintenance and Transfer Using Tikhonov Regularization Approaches
Authors: Kalivas John H. , Siano Gabriel G. , Andries Erik , Goicoechea Hector C.
Published: October 2009

Maintaining multivariate calibrations is essential and involves keeping models developed on an instrument applicable to predicting new samples over time. Sometimes a primary instrument model is needed to predict samples measured on secondary instruments. This situation is referred to as calibration transfer. This paper reports on using a Tikhonov regularization (TR) based method in both cases. A distinction of the TR design for calibration maintenance and transfer is a defined weighting scheme for a small set of new (transfer or standardization) samples augmented to the full set of calibration samples. Because straight application of basic TR theory is not always possible with calibration maintenance and transfer, this paper develops a generic solution to always enable application of TR. Harmonious (bias/variance tradeoff) and parsimonious (effective rank) considerations for TR are compared with the same TR format applied to partial least squares (PLS), showing that both approaches are viable solutions to the calibration maintenance and transfer problems.
Fast Low Frequency (Down to 10 cm−1) Multichannel Raman Spectroscopy Using an Iodine Vapor Filter
Authors: Okajima Hajime , Hamaguchi Hiro-O
Published: October 2009

We have constructed a multi-channel Raman spectrometer that is capable of recording the low frequency region down to 5 cm−1 with a measurement time of a few tenths of a second. An iodine vapor filter, which uses a narrow (∼0.03 cm−1) absorption line of iodine for Rayleigh scattering elimination, is combined with a multi-channel Raman spectrometer composed of a single polychromator and a charge-coupled device (CCD) camera. Thanks to the high Rayleigh scattering elimination efficiency of the filter, which is over 106, Raman spectra of microcrystalline l-cystine from −300 cm−1 to 1000 cm−1 are simultaneously measurable with a small gap of 10 cm−1 (–5 cm−1 to 5 cm−1). Although raw spectra contain many sharp spikes due to the fine structures of iodine absorption, they can be correctly compensated with the use of a transmittance spectrum measured under the same experimental conditions. Many Raman bands including the 9.8 cm−1 band are measured with a high signal-to-noise ratio in both the Stokes and anti-Stokes sides with a measurement time as short as 0.2 s.
Analysis of Reflectance and Transmittance Measurements on Absorbing and Scattering Small Samples Using a Modified Integrating Sphere Setup
Authors: Jernshøj K. D. , Hassing S.
Published: October 2009

The aim of the present paper is to analyze reflectance and transmittance measurements on small scattering and absorbing samples. The long term goal is to perform quantitative, spectroscopic in vivo measurements of pigments in small samples of plant material. Small samples such as small leaves constitute a special experimental challenge in cases in which the sample beam has a larger cross-sectional area than the sample. The experimental errors introduced when measuring reflectance and transmittance on small absorbing and scattering samples are investigated theoretically and experimentally by using a blue polyester sample as an appropriate test sample. The experiments are performed with either a mask or a lens setup combined with a mask inserted in the sample beam. In particular, the errors introduced in the reflectance measurements can be very large and larger than 100%. It is shown that any direct illumination of the mask must be avoided. To obtain more accurate values for the reflection coefficient it is necessary to combine the mask with a focusing lens system, adjust the mask and sample very carefully, and choose the ratio between the aperture of the mask and the beam area as large as possible. In the case of transmittance measurements, it is shown that the combination of a special sample fixture and a lens system gives rise to smaller errors compared to the errors introduced by the mask alone or the mask combined with a focusing lens system.
Influence of Different Metal Matrices on Manganese Signal Response in Laser Ablation Inductively Coupled Plasma—Mass Spectrometry
Authors: Usero R. , Coedo A. G. , Dorado M. T. , Padilla I.
Published: October 2009

Laser ablation inductively coupled plasma–mass spectrometry (LA-ICP-MS) is applied for the quantitative determination of manganese concentration in metal samples. A set of Certified Reference Materials, with different matrix elements (Fe, Cu, Ni, Co, Al) and with certified Mn values, were analyzed. Absorption and plasma break-down depend on the solid phase; as a result, there are differences in mass ablation rates that influence the Mn signal response. In order to be able to compare Mn signals, the relative element-dependent response of tested metal matrices was determined from the ablation of Fe, Cu, Ni, Co, and Al pure metal targets. Relative sensitivity factors (RSFs), calculated as the ratio of the signal intensity of 59Co, 58Ni, 63Cu, and 27Al to the signal intensity of 56Fe, were: 0.79, 0.71, 0.74, and 0.51, respectively. All the isotope signals were matched to the value that should correspond to the relative abundance of 56Fe (91.75%). These experimentally determined RSFs were applied for compensating the observed differences. For quantitative measurements a set of CRM carbon steel samples (SS-451/1 to SS-460/1), with Fe contents of approximately 98%, was used for calibration. The samples with different matrices were measured using the main matrix element as internal standard; for this purpose, the measured intensity was firstly extrapolated, from their content in the sample, to the value that should correspond to a content of 98% and, after, was corrected with the calculated RSF. The developed quantification approach provides manganese results with deviations of 5–10% from the certified values, with relative standard deviations of 3–8%.
Determination of the Hydroxy and Carboxylic Acid Groups in Natural Complex Mixtures of Hydroxy Fatty Acids by 1H Nuclear Magnetic Resonance Spectroscopy
Authors: Sousa Andreia F. , Gandini Alessandro , Silvestre Armando J. D. , Neto Carlos Pascoal
Published: October 2009

The use of trichloroacetyl isocyanate (TAI) to mark both hydroxyl and carboxyl groups borne by the hydrolysis or methanolysis of suberin fragments (a complex mixture of hydroxy fatty acids), allowed the quantitative assessment of the ratio between carboxyl and hydroxy groups, as well as the ratio between primary and secondary hydroxy groups, to be carried out reliably by 1H nuclear magnetic resonance (NMR) spectroscopy. All the samples thus analyzed displayed an excess of CO2H (or CO2CH3) functions with respect to the OH counterparts, albeit to a variable extent, depending on the procedure adopted to isolate the suberin fragments. The precise knowledge of the molar ratio of these two reactive moieties is fundamental for the correct utilization of suberin monomers in polymerization reactions leading to aliphatic polyesters.
In situ Evaluation of Net Nitrification Rate in Terra Rossa Soil Using a Fourier Transform Infrared Attenuated Total Reflection 15N Tracing Technique
Authors: Changwen Du , Linker Raphael , Shaviv Avi , Jianmin Zhou
Published: October 2009

Nitrification and mineralization of organic nitrogen (N) are important N transformation processes in soil, and mass spectrometry is a suitable technique for tracing changes of 15N isotopic species of mineral N and estimating the rates of these processes. However, mass spectrometric methods for tracing N dynamics are costly, time consuming, and require long and laborious preparation procedures. This study investigates mid-infrared attenuated total reflection (ATR) spectroscopy as an alternative method for detecting changes in 14NO3–N and 15NO3–N concentrations. There is a significant shift of the v3 absorption band of nitrate according to N species, namely from the 1275 to 1460 cm−1 region for 14NO3− to the 1240–1425 cm−1 region for 15NO3−. This shift makes it possible to quantify the N isotopes using multivariate calibration methods. Partial least squares regression (PLSR) models with five factors yielded a determination error of 6.7–9.2 mg N L−1 for aqueous solutions and 5.9–7.8 mg N kg−1 (dry soil) for pastes of a Terra rossa soil. These PLSR models were used to monitor the changes of 15NO3–N and 14NO3–N content in the same Terra rossa soil during an incubation experiment in which [15NH4]2SO4 was applied to the soil, allowing the estimation of the contributions of applied N and mineralized N to the net nitrification rate, the potential losses of the applied 15NH4–N, and the net mineralization of soil organic N.
Some New Upper Limits of Isotopic Abundance by Mass Spectrometry
Authors: Leipziger F. D.
Published: October 2009

Using a spark source mass spectrograph, a search has been made for undiscovered naturally occurring isotopes of low abundance None was found, although the spark source instrument permitted examination of elements that have not been analyzed in this context for many years. The ability of the instrument to ionize all elements and the ease with which the rarer isotopes may be seen allowed upper limits of <0 000001 atom % to be placed on some isotopes. Be, P, Mn, Co, As, Rh, Au, and Bi were confirmed as monoisotopic.
Attenuated Total Reflectance Effects with Different Prisms
Authors: Polchlopek Stanley E.
Published: October 2009

The attenuated total reflectance technique produces infrared spectra that are comparable to those obtained by the transmission technique if consideration is given to the choice of a prism material. The material should be selected on the basis of the refractive index of the sample. The ratio between the refractive index of the sample and that of the prism will define a range of incident angles within which spectra can be obtained Outside of this range, spectra will either be weak or show the distorting effects of refraction
Properties and Behavior of the Acetoxy Group in Ultraviolet Absorption Spectroscopy
Authors: Vandenbelt J. M.
Published: October 2009

The acetoxy group, -O•COCH3, iS shown to be an extremely weak electron contributor by examinations of its benzenoid spectra in solvents ranging from non-polar to very polar. Its displacing power is similar to, but even less than, that of an alkyl group.
The Effects of Various Grades of Graphite Electrodes on the Carrier Distillation of Impurities in U3O8
Authors: Pepper C. E. , Pardi A. J. , Atwell M. G.
Published: October 2009

Seven grades of graphite electrodes were evaluated for their effects upon the carrier distillation excitation of impurities in U3O8. Two carrier materials, AgCl-LiF (11.1) and Ga2O3, were independently investigated using a Wadsworth mount spectrograph and a Quantometer Time resolved spectra for 19 impurities were made by recording the instantaneous response of each impurity in the arc for each type of graphite electrode. Elemental sensitivity comparisons were made from the measured area under each spectral recording.

The analytical precisions of the elements (B, Cr, Cu, Fe, Mn, Ni, and Si) for each graphite type were determined from replicate analyses of common samples. The comparative precision data show that a selection of a graphite type, which provides the greatest advantages for determining impurities in U3O8 with carrier distillation techniques, can be made
An Apparatus for the Vaporization-Concentration Method of Spectrochemical Analysis
Authors: O'Connell Robert F.
Published: October 2009

An apparatus for using the vaporization-concentration method of separation of impurities for spectrochemical analysis of refractory materials is described The unit is portable and can be used with controlled atmospheres at either positive or negative pressures. A temperature of over 2300°C can be attained in less than one minute. Temperature is read with a disappearing filament optical pyrometer and is controlled by variations of the input voltages by means of two autotransformers Several other possible applications of the unit are also suggested.
A Modified Rotating Disc Technique Applied to the Determination of Carbon in Sulfur by Emission Spectroscopy
Authors: Guidry J. W. , Matson R. F. , Wiewiorowski T. K.
Published: October 2009

A modified rotating disc technique has been developed. The technique should have application to a variety of elements and samples. It could be particularly useful when applied to materials of low electrical conductivity.

In this paper, the applicability of the new technique is evaluated as applied to the determination of the carbon content in Frasch process sulfur. The technique consists of pressing into the form of a disc a mixture of sulfur and metal powder. This disc is of such dimensions that it will fit on the mandrel of the conventional rotating mechanism A spark is maintained between the disc and a metal counter electrode. The carbon content is measured by the intensity of carbon 2478 3 A using as an internal standard an appropriate line of the metal used in the mixture
Spectrochemical Analysis of Aqueous Solutions by the Plasma Jet
Authors: Serin P. A. , Ashton K. H.
Published: October 2009

The effects of tangential gas flow, arc current, and water irascible solvents on the sensitivity of the plasma jet source, when used with aqueous solutions, have been studied. The optimum conditions for sensitivity have been established and the use of certain mixed aqueous/organic media have been found to improve the limits of detection significantly The effects of hydrochloric, nitric, and sulphuric acid were investigated and found to depend on the nature of the acid but not on the concentration. The matrix effect was found to be less severe than with many methods of excitation. Two examples of the application of the plasma jet to analytical problems are reviewed briefly.
A Study of the Efficiency of Spectrochemical Buffers Part II. Influence of Buffer Anions
Authors: Maritz F. R. , Strasheim A.
Published: October 2009

Using the unit area integration method for the calculation of buffer efficiency, the buffer efficiency index values, (UA)M' and (UA)T' were calculated for the sulphate, chloride, carbonate, borate, fluoride, and nitrate anions as the potassium and barium salts. It was found that the efficiency of the buffer anion is markedly influenced by the associated cation.
Source and Multiplier Modifications of a Time-of-Flight Mass Spectrometer to Increase Sensitivity
Authors: Rohwedder W. K. , Selke E. , Bitner E. D.
Published: October 2009

The usefulness of a gas chromatograph and a mass spectrometer in tandem to analyze odor constituents is limited by the sensitivity of the mass spectrometer and by the large amount of helium carrier gas compared with the amount of sample A time-of-flight mass spectrometer was fitted with a tightly enclosed source and operated in a continuous ionization mode to increase instrument sensitivity A gate pulse was applied to the front end of the magnetic electron multiplier to eliminate the electrons due to the helium pulse before they reached the multiplier dynode strips This procedure prevented saturation of the multiplier by the helium carrier gas.
A Study of the Sources of Errors in the Application of the Ponderal Ratios Method in Flame Photometry
Authors: Ramírez-Muñoz J. , Carrillo-García A. , Díz-Hernández Y. , Tavera-Beltrán H.
Published: October 2009

The sources of error in the application of the ponderal ratios in flame photometry were calculated from the results of the analysis of solutions containing copper and zinc Deviations during calculations cause differences in the equations of the correction curves. These differences permit deriving equations for calculating variation of the correction factors and calculated concentrations. The deviations found in the calculated concentrations by the ponderal ratios method are much smaller than those usually found in flame-photometric work.
The Spectrochemical Estimation of Thallium in Granites and in Manganese Nodules
Authors: Willis J. P. , Kaye M. , Ahrens L. H.
Published: October 2009

Quantitative dc arc techniques are described for estimating thallium in two distinctly different types of geological material, granitic rocks and manganese nodules. Thallium is not normally detectable in granite with average concentration of about one ppm. A highly sensitive special procedure of direct excitation has been developed so that this element may now be estimated in granites and related rocks routinely. The thallium concentration in manganese nodules is relatively high (about 50 ppm), but interference from nickel must be drastically suppressed and sample extrusion prevented before a quantitative estimation can be carried out. Details are given of the solution to these problems using K2SO4 as the diluent.
Infrared Spectroscopy of Biological Materials
Authors: May Leopold
Published: October 2009

The application of infrared spectroscopy to various problems in the biological field is illustrated by considering its use in the structural determination of proteins and a clinical situation. Sampling problems with biological materials are discussed With the advent of the far-infrared spectrophotometer the study of biological materials in the far-infrared region is now possible Typical results with various material such as tissue and macromolecular components of the tissues are shown. The far-infrared spectra of amino acids are discussed
The Identification of Major Infrared Absorbing Components of Human Urine
Authors: Rozelle L. T. , Hallgren L. J. , Bransford J. E. , Koch R. B.
Published: October 2009

The infrared spectra of normal and diabetic human urine were studied and the absorption peaks identified The major infrared absorbing components of normal urine were found to be urea, mono-and di-hydrogen phosphates, and sulfates Glucose absorption peaks were readily identified in the diabetic urine spectra “Synthetic” urine solutions were prepared which yielded spectra matching those of human urine samples. This infrared technique is shown to provide a basis for a simple and rapid analysis of these major components of urine.
Proton Magnetic Resonance Spectra of Some Organosulfur Compounds
Authors: Purcell J. M. , Susi H.
Published: October 2009

The proton magnetic resonance spectra of various sulfur derivatives of long-chain carboxylic acids have been studied The types of compounds studied include those where the methylene chain is interrupted by a sulfide or a sulfone group and those where the carboxyl group has been replaced by –SO3– or –C(=O)S–. The spectral effects produced by the sulfur-containing groups are discussed. The effect of the sulfur group in sulfides and sulfones is compared with the effect of an oxygen atom in a similar environment. The effect of the –SO3– and –C(=O)S– groups on neighboring methylene groups is compared with the effect of the carboxyl group.
New Spectra-Structure Correlations of Aliphatic Ketones
Authors: Gianturco M. A. , Pitcher R. G.
Published: October 2009

The study of the spectra of thirty-six aliphatic ketones in the seven to ten micron region has led to the recognition of bands which permit the facile differentiation of ketones of the three following types-CH3COCH2R, CH3CH2COCH2R, and RCH2CH2COCH2CH2R. The differentiation is based upon the fact that the spectra of methyl ketones show bands at 7.38 and 8 60 microns, while those of ethyl ketones have a characteristic band at 9 03 microns The 9 03 micron band in the spectra of ethyl ketones is in addition to bands at 8.60 and 8 82 microns, which are present also in the spectra of ketones of the type RCH2CH2COCH2CH2R (R≠H).
Performance of Lead Hollow Cathode Lamps for Atomic Absorption Spectroscopy
Authors: Slavin Walter , Manning David C.
Published: October 2009

The use of neon as filler gas in lead hollow cathode lamps provides considerably more light energy than was available with earlier lamps. The spectroscopic performance of these lamps is reported as a function of gas fill, lamp current and spectral bandpass The detection limit for the lead analysis is shown to be 0.03 ppm lead in aqueous solutions with the new lamps and particular atomic absorption instrumentation
Background Control in Direct Reading Analysis of Stainless Steels
Authors: Kennedy W. R.
Published: October 2009

Variable background from alloy to alloy in direct reader analysis of stainless steels affects working curves adversely Spectrographic evidence shows that its effect can be photometrically removed Its influence can be minimized by use of excitation producing a “black burn” using argon shielding of the analytical gap in a point-to-plane arrangement. Automatic dynamic background correction is accomplished with production instruments based on a method of Weekley and Norris.
Identification of Chemical Species in a Plasma by Emission Spectroscopy
Authors: Raisen Elliott , Carrigan Richard A. , Raziunas Victor , Loseke W. A. , Grove E. L.
Published: October 2009

Optical spectroscopy was used to identify the chemical species and the state of excitation of these species in argon, air, and nitrogen plasmas. The 2400 to 8800 A wavelength region was studied. Coppertungsten and graphite-graphite electrodes were used. The species observed were Ar, Ar+, O, N, N2, N2+, C, C2, and CN, the latter three being due to graphite electrodes. The major species found correlated with those species predicted from thermodynamic calculations in air. However, certain species, NO and O2, were not observed.
Beryllium Air Monitor
Authors: Rozsa J. T. , Stone J. , Uguccini O. W. , Kupel R. E.
Published: October 2009

An automatic air sampling system has been combined with a direct reading spectrograph into a mobile cabinet for the continuous quantitative determination of beryllium particulate matter in air. An analysis is reported every 75 sec with a precision of about 20% at the 95% confidence level. Sensitivity is about 0.5 μg/m3 beryllium.
Data Processing Techniques for Improved Spectrochemical Measurements with Photodiode Array Spectrometers
Authors: Lepla Keith C. , Horlick Gary
Published: October 2009

A number of data processing and data acquisition methods are presented that enhance the performance of a photodiode array (PDA) spectrometer. Zero-filling or Fourier-domain interpolation is used to interpolate peak shapes. This improves the accuracy and precision of spectral peak height and position measurements and can be used to overcome spectral line/diode registry effects. A procedure is presented for the automated calibration and recalibration of the wavelength window measured with a photodiode array spectrometer. This method is based, in part, on cross-correlation of spectral patterns. Finally it is shown that by programming of the integration time, several spectra can be combined into a single wide-dynamic-range spectrum. Taken as a whole, these data processing and acquisition techniques improve the accuracy, precision, and dynamic range of spectrochemical data acquired with a PDA spectrometer. This is illustrated by using the system for the rapid measurement of excitation temperatures of plasma sources.
Spatial Distribution of Vacuum Ultraviolet Radiation in an Inductively Coupled Plasma
Authors: Babis Jeffery , Pilon Michael J. , Denton M. Bonner
Published: October 2009

Spatially resolved emission maps of an ICP as a function of torch design, power, and gas flow rate have been obtained for O, N, Cl, Br, and C in the vacuum ultraviolet with the use of an Abel inversion data reduction algorithm. Two coolant tube configurations were studied, one a standard strait coolant tube with a “bell”-style collar, and a second with a “T”-shaped sidearm tube. The studies show that the maximum emission intensities for Br and Cl occurred below the top of the coolant tube and that the N 149.28-nm emission cannot be observed for the bell collar configuration. The investigation of the T-tube configuration yielded useful information for all elements studied, with optimum observation heights ranging from 8 mm above the load coil for C at 165.70 nm to 20 mm above the load coil for O at 130.49 nm. In most cases, the maximum intensity is observed in the center of the discharge. Signal-to-noise studies indicate that the highest power practical with the minimum flow rate possible should be used for the analysis of the four nonmetals investigated.
An Atmospheric-Pressure Glow Discharge Ionization Source
Authors: Sofer Irit , Zhu Jianzhong , Lee Hwa-Sung , Antos William , Lubman David M.
Published: October 2009

In this work, a novel atmospheric-pressure glow discharge source is explored. This discharge operates in the 1 kV range at typically 50–250 μA current in atmospheric-pressure helium. The characteristic I vs. V curve for a glow discharge is observed, and the discharge can operate in the positive or negative modes. The background ions observed in the positive mode from the atmospheric-pressure ionization (API) cell in the mass spectrometer are characteristic of water clusters from background water in the cell, and almost no helium background ions are detected. This atmospheric-pressure glow discharge source has been used to ionize various small biologicals, drugs, peptides, and explosives analogs that have been introduced into the API cell via a direct insertion probe. The resulting mass spectra exhibit generally the MH+ with minimal or no fragmentation in the positive mode, indicating that ionization of the analyte occurs softly through proton transfer from water clusters. Detection limits in the low-pg range have been obtained in both the positive and negative modes.
GC/FT-IR Analysis of Fatty Acid Methyl Esters
Authors: Doumenq P. , Guiliano M. , Bertrand J. C. , Mille G.
Published: October 2009

An analytical method, based on coupled gas capillary chromatography and Fourier transform infrared spectrometry (GC/FT-IR), has been developed to determine the structure of fatty acid mixtures often found in the marine environment. In the case of saturated fatty acids, the method provides useful information concerning chain lengths and the presence of (1) branched methyl groups (iso or anteiso), (2) cyclopropanic structures, and (3) hydroxyl groups (two or three positions). Furthermore, the presence or absence of double bonds, as well as their stereochemistry and their number, in the case of cis polyunsaturated derivatives, can be determined. The method has required the development of a specific GC/FT-IR library of 46 fatty acid methyl esters generally found in the marine environment.
The Effect of Internal Gas Flow on the Spatial Distribution of Sodium Atom within a Graphite Furnace Atomizer
Authors: Huie Carmen W. , Curran Charles J.
Published: October 2009

A laser-based vidicon imaging system has been used to obtain spatially and temporally resolved absorbance profiles of Na atoms within pyrolytic graphite coated and uncoated polycrystalline electrographite tubes under gas-stop and gas-flow conditions in graphite furnace atomic absorption spectrometry. During the initial period of atomization, the spatial distribution of Na indicates that most of the atoms are localized near the bottom of the furnace under the influence of convective flow. This observation suggests that the free Na atoms, upon collisions with the furnace walls, are interacting strongly with the graphite surface. The strength of interaction appears to be stronger for uncoated graphite tubes. After the peak absorbance, the Na atom density is lower near the furnace wall than in the center of the furnace. The observed gradient is likely a result of the Na atoms undergoing a series of redeposition and revaporization reactions with the graphite surface during the course of atom removal.
Matrix Effects Studies with Fused-Silica Aperture Thermospray Sample Introduction to ICP-AES
Authors: Veber Marjan , Koropchak John A. , Conver Timothy S. , Herries John
Published: October 2009

Matrix effects with fused-silica aperture thermospray (FSApT) sample introduction for ICP-AES are found to be higher than those for pneumatic sample introduction. The effects are comparable to those reported for sample introduction to ICP-AES using ultrasonic nebulization with desolvation. The matrix effects for >mg/mL levels of Ca are found to be influenced by the thermospray operating temperature. By the use of higher thermospray temperatures, matrix effects due to transport losses are reduced to low levels, presumably by reduction of primary aerosol particle sizes. Background increases due to higher Ca input with the thermospray system result in small changes in background noise that do not appear to have a large effect on limits of detection (LODs). Matrix effects occurring within the plasma appear to be the primary source of interferences. Ca interferences can also be reduced or eliminated by appropriate adjustment of the aerosol carrier gas flow rate. For simultaneous multielement analysis, a compromise flow rate must be chosen. With the use of such compromise conditions, LODs for a wide range of elements were increased in the presence of Ca, but were on average within a factor of 1.7 of those obtained in the absence of Ca. LODs obtained for analytes in the presence of 1000–3000 μg/mL Ca for FSApT/ICP-AES were all below United States Environmental Protection Agency (EPA) required limits for Toxicity Characteristic Leaching Procedure (TCLP) samples derived from concrete stabilized hazardous waste, while pneumatic sample introduction provided inadequate detection for half the key elements tested.
Infrared Study of Phosphorous Oxychloride and Organophosphorus Compounds Containing the P(=O)Cl2 Group in Dilute Solvent Systems
Authors: Nyquist R. A. , Puehl C. W.
Published: October 2009

The present study has shown that some normal vibrations shift to lower frequency while others shift to higher frequency as the mole % of the solvent system increases. The vP=O mode for compounds containing the P(=O)Cl2 group shifts to lower frequency with increase in the mole % CHCl3/CCl4. The P=O group is believed to be complexed with the solvent system. Both the vasym.PCl2 and vsym.PCl2 modes shift to higher frequency as the mole % CHCl3/CCl4 increases. The application of IR and different solvent systems aids in assigning rotational isomer band pairs.
Surface-Enhanced Raman Scattering (SERS) Study of the Interaction between Hematoporphyrin and Guanine
Authors: Siding Zheng , Jian-Ping Wang , Ji-Yao Chen
Published: October 2009

The interaction between hematoporphyrin and guanine has been investigated by the Raman spectroscopic method. Irradiation of guanine solution mixed with hematoporphyrin was observed through the change in the Raman spectra. It was observed that the band at 1534 cm−1 shifted and the bands at 1274 cm−1 and 1190 cm−1 disappeared in the presence of hematoporphyrin. A prolonged irradiation time of five hours caused the SERS spectra of guanine to disappear. These results indicate that the guanine was modified in the photosensitized reactions in the presence of hematoporphyrin. We used SERS to study the photodynamic modification of nucleic acid base by hematoporphyrin. We found that illumination of guanine and adenine with the 514.5-nm argon-ion laser line in the presence of hematoporphyrin resulted in the selected degradation of guanine.
Detection of Sub-ng/L Actinides in Industrial Wastewater Matrices by Inductively Coupled Plasma-Mass Spectrometry
Authors: Crain Jeffrey S. , Mikesell Barbara L.
Published: October 2009

Inductively coupled plasma-mass spectrometry (ICP-MS) was used to measure ng/L quantities of uranium in solution. Pneumatic nebulization and ultrasonic nebulization were compared. The spectral integration period was varied to study the effects of counting statistics. Analyte detection at m/z 238 was found to be blank limited. Under optimal conditions (i.e., with the use of ultrasonic nebulization and an 11-s integration period per m/z), uranium detection limits (3 σ) at m/z 234 (not blank limited) were found to be 0.1 ng/L in 18-MΩ water. The uranium detection limit at m/z 234 was 0.5 ng/L when a 2.5-g/L NaNO3 solution was nebulized. Normalized instrument response for uranium in 18-MΩ water agreed well with that in 2.5-g/L NaNO3.
Raw Materials for Making Jingdezhen Porcelain from the Five Dynasties to the Qing Dynasty
Authors: Yap C. T. , Hua Younan
Published: October 2009

This is a study of 66 pieces of Jingdezhen porcelain bodies and their relation to 13 raw materials, three of which are kaolin and the rest porcelain stones from Jingdezhen. For Jingdezhen porcelains, the results show that the alumina content increases and silica content decreases as a function of time, except during the Yuan and Ming Dynasties, when this trend was reversed. For raw materials, although kaolin could never be used alone for porcelain production, four of the porcelain stones could be used alone for this purpose during the Five Dynasties and part of the Song Dynasty. However, all porcelains made thereafter have varying amounts of kaolin added to the porcelain stone. Except for a reversal during the Yuan and Ming Dynasties, we found that the amount of kaolin added was a function of time, reaching as high as about 60% during the Qing Dynasty.
Diffuse Reflectance Infrared Spectroscopy: Experimental Study of Nonabsorbing Materials and Comparison with Theories
Authors: Moradic Kamal , Depecker Christophe , Corset Jacques
Published: October 2009

This work presents a comprehensive study of the diffuse reflectance of nonabsorbing powders in the mid-infrared. The changes in the optical and physical parameters of the powder (particle size, granulometric distribution, powder density, refractive index) have been used to get a better understanding of the influence of each parameter on the diffusely reflected intensity, as well as the mechanisms of the light diffusion by the powder. A commercial diffuse reflectance attachment has been tested optically for the accuracy of measurements, the focalization of the incident beam at the sample surface being taken into account. The experimental results have been compared to results of existing diffusion theories. This comparison proves the pertinency of the observed variation of the intensity of the diffusely reflected light with the refractive index which increases from 0 for n = 1 to a maximum and then decreases with n. This behavior is related to the anisotropy of the light diffusion both at the inside and then at the outside of the particles and to the light trapping by total reflection inside the particles.
Dual-Beam Time-Resolved Z-Scan in Liquids to Study Heating Due to Linear and Nonlinear Light Absorption
Authors: Kozich V. P. , Marcano A. , Hernandez F. E. , Castillo J. A.
Published: October 2009

Dual-beam extension of a Z-scan technique has been developed to study the thermal changes in the refractive index resulting from linear and nonlinear absorption in liquids. The experiments were carried out with nanosecond-pulsed Nd:YAG radiation and its second harmonic as the excitation sources and a He-Ne laser as the probe beam. The cw probe radiation enabled us to observe temporal dynamics of the refractive index variations, to select the thermal signal for Z-scan measurement and to measure absolute changes in the refractive index as small as 10−6 due to heating in a number of organic liquids. The temporal shape of the thermal signal is analyzed experimentally and theoretically both in weak and strong phase distortion of the probe wave. Gaussian approximation for the pump and probe beams and the Taylor series decomposition of nonlinear phase distortion term at the exit of the sample are used to describe the thermal signal and to fit experimental data to theoretical models.
Factors Affecting the Spectral Response in a TG/FT-IR Experiment
Authors: Marini A. , Berbenni V. , Capsoni D. , Riccardi R. , Zerlia T.
Published: October 2009

We discuss situations where thermogravimetric/Fourier transform infrared (TG/FT-IR) plots are obtained which differ substantially from the expected ones. The most common of these situations involves samples that release atmospheric components (H2O, CO2) at low temperatures. It is shown that the phenomena are mainly related to the purging action of the carrier gas, which strongly influences the spectroscopic portion of the TG/FT-IR plot. Such an influence, as well as the different situations originating from it, is discussed and explained on the basis of an analogy with the operational mode of a conventional dispersive spectrometer.
Dual-Beam Thermal Lens Measurement of Condensed-Phase Sample at CO2 Laser Wavelengths: Detection of Octadecanoic Acid in Carbon Tetrachloride
Authors: Franko Mladen , Bicanic Dane , Bozóki Zoltán , Jalink Henk
Published: October 2009

Detection of monobasic, straight-chain saturated fatty acid (octadecanoic C18:0) in CCl4, based on the thermal lens effect after excitation by CO2 laser radiation at 934.9 cm−1, is described for the first time. The achieved limit of detection (LOD = 0.3%) is comparable to that of the transmission infrared technique. Possibilities for further improvements in sensitivity and detection limit are also discussed.
New Method to Eliminate the Background Noise from a Line Spectrum
Authors: Iwata Tetsuo , Koshoubu Jun
Published: October 2009

We propose a numerical method to eliminate the background noise from a line spectrum. The background noise is discriminated from signal components by applying a singular value decomposition (SVD) method to a cyclic matrix that is constructed from the spectrum data. The first column of the cyclic matrix is given by the Fourier transform of the spectrum data. Unlike conventional smoothing procedures, the new method gives no distortion to the signal waveform. The details of the method are described. Experimental results applied to FT-Raman spectrum data of carbon tetrachloride are also shown.