Showing papers in "Mikrochimica Acta in 1988"
TL;DR: In this article, a new technique for utilizing near-infrared spectroscopic data for quantitative analysis is proposed, which uses a database of spectra stored in the form of the Fourier transform together with the associated chemical analysis.
Abstract: A new technique for utilising near-infrared spectroscopic data for quantitative analysis is proposed. The method uses a database of spectra stored in the form of the Fourier transform together with the associated chemical analysis. The spectrum of an unknown sample is compared to each member of the database and a small subset of very similar samples is isolated. The analyte value for the unknown is calculated from the analytical values of the subset. Results are given for the application of the method to the analysis of nicotine in tobacco.
49 citations
TL;DR: In this paper, an aircraft version of the high-resolution interferometer sounder (HIS), a Fourier transform spectrometer designed for meteorological applications, has been used to measure the upwelling infrared emission of the earth with a resolving power on the order of 1000.
Abstract: An aircraft version of the high-resolution interferometer sounder (HIS), a Fourier transform spectrometer designed for meteorological applications, has been used to measure the upwelling infrared emission of the earth with a resolving power on the order of 1000. HIS measurements from high-altitude NASA research aircraft have demonstrated that the high radiometric accuracies required for atmospheric temperature and humidity sounding (1°C absolute brightness temperature and 0.1° C RMS reproducibility) can be achieved. Calibration is accomplished using periodic views of two onboard high-emissivity blackbodies, servo controlled to 300 K and 240 K. For an interferometer, this approach relies on careful optical design and alignment to avoid unknown dependence of the responsivity on optical path difference. The aircraft model is a successful prototype for spacecraft versions for weather and climate monitoring.
44 citations
TL;DR: The correspondence analysis proved that the various different bacterial species were clustering in distinct regions of the correspondence maps suggesting that there do exist correlations between spectral data and biochemical/microbiological classification.
Abstract: Correspondence analysis was used to classify the pattern-like FT-IR spectra of intact bacteria. The analysis was performed on a data set of approximately 80 normalized spectral derivatives of a selection of pathogenic bacteria. The correspondence analysis proved that the various different bacterial species were clustering in distinct regions of the correspondence maps suggesting that there do exist correlations between spectral data and biochemical/microbiological classification.
39 citations
TL;DR: A simple and reliable procedure for the determination of platinum including high pressure ashing, separation and detection by graphite furnace AAS has been developed as discussed by the authors, which was put to practical use in the analysis of biotic and environmental materials polluted with platinum in the concentration rangeμg/kg to g/kg.
Abstract: A simple and reliable procedure for the determination of platinum including high pressure ashing, separation and detection by graphite furnace AAS has been developed. It was put to practical use in the analysis of biotic and environmental materials polluted with platinum in the concentration rangeμg/kg to g/kg.
36 citations
TL;DR: In this paper, a survey demonstrates the potential applications of FTIR spectroscopy in wood and wood-product research, e.g. for determination of lignin in woody materials and pulps.
Abstract: Based on own research activities this survey demonstrates the potential applications of FTIR spectroscopy in wood and wood-product research. This rapid method can be used e.g. with success for determination of lignin in woody materials and pulps. Crucial analytical data of lignins were also determined by quantitative evaluation of FTIR data. The degree of substitution of cellulose derivatives can be estimated. The course of delignification during pulping was monitored using transmission and circular ATR cells for the IR spectroscopy of the cooking liquors. Based on these spectra the Kappa number of pulps can be predicted.
36 citations
TL;DR: Two-dimensional IR spectroscopy is used to study atactic polystyrene as mentioned in this paper, which is a technique based on time-resolved detection of IR signals in response to an external perturbation, such as mechanical strain.
Abstract: Two-dimensional infrared (2D IR) spectroscopy is used to study atactic polystyrene. 2D IR is a technique based on time-resolved detection of IR signals in response to an external perturbation, such as mechanical strain. Since different chemical functional groups respond to the applied perturbation at unique and often different rates, characteristic time-dependent variations of the IR-band intensities are observed. Correlation analysis of the dynamic variation of the IR signals yields a new spectrum defined by two independent wave numbers. Peaks located on a 2D IR spectral plane imply interactions and connectivities among chemical functional groups. By spreading convoluted IR bands over two dimensions, the spectral resolution is also greatly enhanced.
35 citations
TL;DR: Ion selective ionophores are described which induce a rejection of Na+ and K+ in solvent polymeric membranes by factors of up to 6300 and 5000, respectively and are candidates for water hardness determination as well as for an Mg2+ assay in blood by chemometric procedures.
Abstract: Magnesium selective ionophores are described which induce a rejection of Na+ and K+ in solvent polymeric membranes by factors of up to 6300 and 5000, respectively. Depending on the membrane composition, ion selective electrodes may be obtained with equal selectivity for Mg2+ and Ca2+ as well as sensors with a discrimination of Ca2+ by a factor up to 8. Sensors of the type described are candidates for water hardness determination as well as for an Mg2+ assay in blood by chemometric procedures.
28 citations
TL;DR: The quasi-reversible nature of the electron transfer reactions of cytochromec occurring at platinum, gold and mercury electrodes has been shown in this paper, where the corresponding experiments were conducted at clean metal surfaces.
Abstract: The heterogeneous electron transfer reactions of cytochromec occurring at platinum, gold and mercury electrodes are shown to be quasi-reversible. In each case the electrodes have not been modified and the cytochromec samples are native. This work extends previous work and demonstrates that biological molecule electron transfer reactions can be studied at clean metal surfaces to gain fundamental knowledge of the mechanisms of these reactions.
26 citations
TL;DR: The analysis of odour components in East Indian Sandalwood Oil (Santalum album L.) and in Patchouli Oil (Pogostemon cablin Benth.) based on GC-, GC-FTIR- and GC-MS-data resulted in the identification of α-santalene,α-santa-al, β-santo-al and epi-β-santisantalal as mentioned in this paper.
Abstract: The analysis of odour components in East Indian Sandalwood Oil (Santalum album L.) and in Patchouli Oil (Pogostemon cablin Benth.) based on GC-, GC-FTIR- and GC-MS-data resulted in the identification ofα-santalene,α-santalal,β-santalal, epi-β-santalal,α-santalol,β-santalol, (E)-β-santalol,α-bergamotol and spirosantalol in Sandalwood Oil and of (−)-patchoulol,α-guaiene,α-patchoulene, seychellene,α-bulnesene, norpatchoulenol and pogostol in Patchouli Oil as the most intense aroma compounds of these oils.
25 citations
TL;DR: Preliminary studies suggest that the new FIIA system is suitable for determining theophylline in serum with acceptable accuracy and precision.
Abstract: A fast, non-equilibrium enzyme-linked flow-injection immunoassay (FIIA) system using an immobilized secondary-antibody reactor is described. The assay method is based on the competition between the enzyme-labeled antigen and analyte (unlabeled antigen) for a limited amount of soluble primary-antibody binding sites. This mixture is then introduced via flow-injection into the secondaryantibody reactor. The reactor bound enzyme activity, as measured by flowing an appropriate substrate solution through the reactor, is inversely proportional to the concentration of free analyte in the sample. By using non-equilibrium conditions, a single assay takes a total time of 13 min or less including regeneration of the reactor. To illustrate the application of this system, theophylline and insulin were chosen as model hapten and macromolecule analytes, respectively. Preliminary studies suggest that the new FIIA system is suitable for determining theophylline in serum with acceptable accuracy and precision.
24 citations
TL;DR: In this article, 15 amino acids were determined as DABSYL (4-4-dimethylaminoazobenzene-4'-sulfonyl chloride) derivative with capillary zone electrophoresis separation and low-power laser-induced thermo-optical detection.
Abstract: Fifteen amino acids are determined as the DABSYL (4-4-dimethylaminoazobenzene-4'-sulfonyl chloride) derivative with capillary zone electrophoresis separation and low-power laser-induced thermo-optical detection. Separation efficiencies are on the order of 200 000 theoretical plates and the detection limit, 3 s, is 200 attomole of glycine injected onto the column. At the detection limit, 0.7 attomole of glycine is present within the 40 picoliter detection volume.
TL;DR: In this paper, several approaches are investigated to provide the reagents in immobilized or solid-state format for the analysis of luminol chemiluminescence in flow injection systems.
Abstract: To facilitate the application of luminol chemiluminescence in analysis, several approaches are investigated to provide the reagents in immobilized or solid-state format. The approaches are demonstrated with flow injection systems. Luminol is covalently bound or adsorbed to the surface of small support particles and packed into flow-through reactor/detector cells. The catalyst can be either covalently immobilized heme-containing species or a positively-biased electrode in an electrochemical cell. Peroxide can be obtained electrochemically at a negatively-biased electrode. These immobilized reagent systems can be combined to yield single-channel flow systems for determination of hydrogen peroxide (0.15μM detection limit) or luminol (0.1 nM detection limit).
TL;DR: In this article, the technique of FT-IR/microscopy is applied to a variety of problems faced by the forensics chemist, these are as varied as the identification of drugs and fibers to the assignment of the origin of a paint sample.
Abstract: The technique of FT-IR/microscopy is applied to a variety of problems faced by the forensics chemist These are as varied as the identification of drugs and fibers to the assignment of the origin of a paint sample Our efforts in the effective utilization of FT-IR/microscopy in this area and usage of new data bases to aid in identifications are discussed
TL;DR: The infrared spectra of single human normal and leukemic lymphocytes have been obtained and opens up the possibility in determining the early stages of leukemia, in following the course of patients under therapy, and in evaluation of the residual neoplastic disease.
Abstract: The infrared spectra of single human normal and leukemic lymphocytes have been obtained by means of the microscope-FT-IR system. Substantial differences between the two kinds of cells have been observed at level of the O-P-O vibrations of the DNA and of the proteic components. This determination opens up the possibility in determining the early stages of leukemia, in following the course of patients under therapy, and in evaluation of the residual neoplastic disease.
TL;DR: In this article, the effluent from a microbore HPLC is continuously deposited onto and eliminated from the surface of a circular rotating germanium crystal that has been aluminum coated on its opposite side.
Abstract: A method for HPLC/FTIR is discussed in which the effluent from a microbore HPLC is continuously deposited onto and eliminated from the surface of a circular rotating germanium crystal that has been aluminum coated on its opposite side. After deposition, the germanium disk is again rotated, this time in the sample compartment of an FTIR spectrometer while reflectance-absorbance infrared spectra are continuously collected. The novel germanium-aluminum deposition surface allows collection of reflectance-absorbance spectra that are free of the degrading effects of superposition phenomena characteristic of reflectance-absorbance spectra obtained on metal surfaces. Furthermore, germanium is impervious to aqueous solvent mixtures and, therefore, allows for the direct deposition of reversed phase separations, including those requiring acid modified mobile phases.
TL;DR: Vibrational circular dichroism spectra of poly-L-tyrosine, poly- L-phenylalanine, myoglobin andβ-lactoglobulin were measured in solution for the amide I region, consistent with previous determinations of the secondary structures of these species.
Abstract: Vibrational circular dichroism spectra of poly-L-tyrosine, poly-L-phenylalanine, myoglobin andβ-lactoglobulin were measured in solution for the amide I region. These measurements are shown to be consistent with previous determinations of the secondary structures of these species.
TL;DR: In this paper, the structural evolution of the syndiotactic poly(styrene) system from the ordered to the amorphous phase has been followed, and temperature dependent FTIR spectra have been recorded.
Abstract: Highly syndiotactic poly(styrene) shows higher crystallinity and a higher melting point than the corresponding isotactic material. Temperature dependent FTIR spectra have been recorded and the structural evolution of the system from the ordered to the amorphous phase has been followed.
TL;DR: In this article, a study of the chemical composition of renal stones is presented for understanding their etiology, and the therapy for the stone disease is usually based on the analysis of calculi permitting a porper management of the disease and the prevention of its recurrence.
Abstract: A study of the chemical composition of renal stones is important for understanding their etiology. And the therapy for the stone disease is usually based on the analysis of calculi, permitting a porper management of the disease and the prevention of its recurrence. FTIR spectroscopy has been used for urinary stones analysis. The routine, easy and rapid measurements give unambiguous information about the stone composition. Especially a precise wavelength scale of the Fourier method is helpful here. A relatively good spatial resolution is important as very often the stones are composed of core and various layers of different chemical composition. A quantitative determination of the proportion of various materials in calculi is also possible.
TL;DR: In this article, a systematic experimental comparison of these techniques has been made in order to make proper use of their mutual advantages in infrared spectroscopy, including the KBr pellet technique and ATR spectrograms.
Abstract: The growing capabilities of FTIR spectrometers and computers have opened the use of new sample preparation techniques in infrared spectroscopy. In addition to the established KBr pellet technique and ATR spectroscopy, diffuse reflectance and photoacoustic spectroscopy are increasing in importance. A systematic experimental comparison of these techniques has been made in order to make proper use of their mutual advantages.
TL;DR: In this article, the antimicrobial silane SiQAC is stable hydrolysis in aqueous solution at near neutral pH values, but not accompanied by condensation of the silanol groups.
Abstract: CIR sampling has been used to demonstrate that the antimicrobial silane SiQAC is stable hydrolysis in aqueous solution at near neutral pH values. However, rapid hydrolysis occurs in mildly acidic solutions, but not accompanied by condensation of the silanol groups. After hydrolysis, condensation to form siloxane bonds is rapid in basic solution. The degree of hydrolysis is increased in the presence of silica gel. The silane on silica gel is quite durable towards desorption when contacted with water.
TL;DR: In this article, a complete integrated system for TGA/FT-IR analysis is described, which consists of a TGA and FT-IR analyzer with a complete characterization of materials in terms of thermal stability and decomposition mechanisms.
Abstract: Thermogravimetric analysis (TGA) is a widely employed technique for measuring the change in weight of a sample as a function of temperature or time in a controlled atmosphere. FT-IR has been utilized with success in the identification of gases [1]. The combination of these two techniques permits a complete characterization of materials in terms of thermal stability and decomposition mechanisms [2]. A complete integrated system for TGA/FT-IR analysis is described.
TL;DR: In this paper, the determination of ultratrace concentrations of mercury in biological materials was performed using cold vapour atomic absorption spectrometry using stannous chloride reduction and two-stage gold amalgamation.
Abstract: The paper describes the determination of ultratrace concentrations of mercury in biological materials. Samples were digested in nitric acid under pressure in a polytetrafluoroethylene bomb. Mercury was determined in the digest solution by cold vapour atomic absorption spectrometry using stannous chloride reduction and two-stage gold amalgamation. The detection limit is 0.12 ng. Analysis of several certified reference materials yielded results in excellent agreement with the certified values. The results for blood serum of several subjects ranged from 0.2 to 0.8μg 1−1.
TL;DR: In this article, the variation in relative elemental concentrations among a series of coal macerals belonging to the vitrinite maceral group was determined using laser micro mass spectrometry (LAMMS).
Abstract: The variation in relative elemental concentrations among a series of coal macerals belonging to the vitrinite maceral group was determined using laser micro mass spectrometry (LAMMS). Variations in Ba, Cr, Ga, Sr, Ti, and V concentrations among the coals were determined using the LAMM A-1000 instrument. LAMMS analysis is not limited to these elements; their selection illustrates the application of the technique. Ba, Cr, Ga, Sr, Ti, and V have minimal site-to-site variance in the vitrinite macerals of the studied coals as measured by LAMMS. The LAMMS data were compared with bulk elemental data obtained by instrumental neutron activation analysis (INAA) and D. C. arc optical emission spectroscopy (DCAS) in order to determine the reliability of the LAMMS data. The complex nature of the ionization phenomena in LAMMS and the lack of standards characterized on a microscale makes obtaining quantitative elemental data within the ionization microvolume difficult; however, we demonstrate that the relative variation of an element among vitrinites from different coal beds in the eastern United States can be observed using LAMMS in a “bulk” mode by accumulating signal intensities over several microareas of each vitrinite. Our studies indicate gross changes (greater than a factor of 2 to 5 depending on the element) can be monitored when the elemental concentration is significantly above the detection limit. “Bulk” mode analysis was conducted to evaluate the accuracy of future elemental LAMMS microanalyses. The primary advantage of LAMMS is the inherent spatial resolution, ~ 20μm for coal. Two different vitrite bands in the Lower Bakerstown coal bed (CLB-1) were analyzed. The analysis did not establish any certain concentration differences in Ba, Cr, Ga, Sr, Ti, and V between the two bands.
TL;DR: In this article, the Fourier transform infrared attenuated total reflectance (FT-IR-ATR) technique was used to measure the SiOH and SiH contents in the thermal oxide films grown on Si wafers.
Abstract: FT-IR-ATR (Fourier transform infrared attenuated total reflectance) technique was used to measure the SiOH and SiH contents in the thermal oxide films grown on Si wafers. It was found that the SiOH groups in the bulk could be eliminated by low temperature annealing, whereas SiOH at the Si/SiO2 interface could only be removed by high temperature annealing. It was also found that gamma ray irradiation generated SiOH and SiH in the thin oxide film.
TL;DR: Polarization modulated IRRAS is a new differential method of Fourier transform infrared spectroscopy, used to investigate ultrathin films as discussed by the authors, which has high surface sensitivity, perfect environmental signal rejection and easy to get conformational information on surface molecules.
Abstract: Polarization modulated IRRAS is a new differential method of Fourier transform infrared spectroscopy, used to investigate ultrathin films. Spectra of a single L.B. monolayer of cadmium arachidate and of a 100 A thick polymer film are presented in order to illustrate the main advantages of this method: high surface sensitivity, perfect environmental signal rejection and easy to get conformational information on surface molecules.
TL;DR: In this article, a new high performance liquid chromatography (HPLC) interface with Fourier transform infrared (FT-IR) spectrometry is studied. This interface removes HPLC solvents prior to infrared detection, making it possible to obtain spectra from reverse phase chromatography with no interferences from residual solvent.
Abstract: The development of a new high performance liquid chromatography (HPLC) interface with Fourier transform infrared (FT-IR) spectrometry is currently being studied. This interface removes HPLC solvents prior to infrared detection. The solvent elimination properties of this interface make it possible to obtain spectra from reverse phase chromatography with no interferences from residual solvent.
TL;DR: In this article, Fourier self-deconvolution has been used for band enhancement in NIR spectra, which preserves peak areas so that the deconvolted results may prove advantageous in using multilinear calibration techniques.
Abstract: A demonstrated analytical tool for band enhancements in the mid-IR, Fourier self-deconvolution can serve similarly in the analysis of NIR spectra even when the spectra, obtained with dispersion instruments in the diffuse reflectance mode, have broad, overlapping bands not easily resolved. Unlike derivative enhancement methods, Fourier self-deconvolution preserves peak areas so that the deconvolted results may prove advantageous in using multilinear calibration techniques. Band enhancements of both synthetic and real spectra are discussed.
TL;DR: In this paper, the influence of various factors such as solubility, the oxidation of the membrane, and the contamination of the solution, on the experimental values of the selectivity coefficients of solid state sulphide ion selective electrodes is discussed.
Abstract: The influence of various factors such as solubility, the oxidation of the membrane, and the contamination of the solution, on the experimental values of the selectivity coefficients of solid state sulphide ion selective electrodes is discussed. A new method for the evaluation of very small selectivity coefficients, based on the addition of reagents forming complexes or insoluble salts with the main ion, is proposed. By means of this method, selectivity coefficients for silver, copper, cadmium and lead ion selective electrodes have been determined, which are in far better agreement with thermodynamic values than those described in the literature.
TL;DR: In this article, the authors describe the optical and electronical concept of a new type of interferometer and demonstrate the performance of the instrument by measurements of gas absorption spectra and laser emissions.
Abstract: The paper describes the optical and electronical concept of a new type of interferometer. The performance of the instrument was demonstrated by measurements of gas absorption spectra and laser emissions. Measured data are compared to theoretical line-by-line calculations.
TL;DR: In this article, the authors used FT-IR spectroscopy to characterize the structure hydration and dehydration of mucin in vitro and found that both the protein chain and carbohydrate moiety are hydrated with the water molecules.
Abstract: FT-IR spectroscopy was utilized to characterize the structure hydration and dehydration of mucin in vitro. The results indicated that both the protein chain and carbohydrate moiety are hydrated with the water molecules. In addition, the hydration and dehydration mechanism of mucin are quite different in H2O and D2O media.