Methods of assessment of atropine and scopolamine levels in transdermal permeation

Three methods of atropine and scopolamine determination in transdermal permeation have been developed. Radiometric determination seems to be an excellent, quick and extremely sensitive method, which ought to be preferred when working with biological systems. The radioreceptor analysis is of group specificity. It can be used to advantage in monitoring atropine plasma concentrations exceeding 1.5 ng cm^–3 and scopolamine concentrations above 50 pg cm^–3. GC/MS provides adequate specificity and sensitivity for the determination of therapeutic levels of atropine and scopolamine in blood. The sensitivity of this method is approximately 1–2 ng cm^–3.     

Water sorption properties of carbonized layers produced by controlled B<Superscript>+</Superscript> bombardment of thin polyimide and polysulfone films

Thin polyimide (PI) and polyethersulfone (PES) films are widely used as functional layers for microelectronic sensors. Ion implantation modifies the layer structure and morphology of these polymers and hence results in new mechanical and optical properties. However, ion-modified layers also show a change in sensitivity to moisture uptake under specific conditions. This is important for developing humidity sensors. Therefore, the water sorption ability of such modified polymer layers is studied by spectroscopic ellipsometry under definite relative humidity conditions (1–95%). Swelling data were obtained by fitting procedures based on changes of effective layer thickness and optical constants due to water uptake. Irradiation doses from 0.5 to 5×10¹⁵ B⁺ cm^–2 at an energy of 180 keV were used for polymer modification. At irradiation doses from 0.5 to 0.7×10¹⁵ B⁺ cm^–2, the maximum out-of-plane swelling is reached. At higher doses >2×10¹⁵ B⁺ cm^–2, the swelling decreases and corresponds to values of the pure polymer layers. The wetting properties of the layer surfaces determined by contact angle measurements are important to explain this behavior.     

Diffuse reflectance spectra of iron(III) vanadates

The electronic spectra of solid iron(III) vanadates FeVO₄ and Fe₂V₄O₁₃ were investigated by the diffuse reflectance technique in the spectral range 12 500–50 000 cm⁻¹. The spectra of investigated vanadates contain 2–3 intensive CT bands in the UV region and two lowest energy d–d bands in the 12 000–22 000 cm⁻¹ range. The presence of the weak bands for FeVO₄ and Fe₂V₄O₁₃ at 16 500 cm⁻¹ and 20 500 cm⁻¹ points to the lattice deffects (oxygen deficiency and the presence of the V⁴⁺ ions) in the structure of investigated vanadates.     

IR-analysis of H-bonded H2O on the pure TiO2 surface

The surface state of optically pure polydisperse TiO₂ (anatase and rutile) was determined by infra-red (IR) spectroscopy analysis in the temperature range of 100–453 K. Anatase A300 spectrum, contrary to rutile R300 one, has a broad three-component absorption band with peaks at 1048, 1137 and 1222 cm⁻¹ in the spectral range of δ(Ti–O–H) deformation vibrations. For rutile R300 we observed a very weak band at 1047 cm⁻¹, and for the thermal treated rutile R900 these bands were not appeared at all. The analysis of temperature dependencies for the mentioned absorption bands revealed the spectral shift of 1222 cm⁻¹ band towards the high frequencies, when the temperature increased, but the spectral parameters of 1137 and 1048 cm⁻¹ bands remained the same. The temperature of 1222 cm⁻¹ band maximum shift was 373–393 K and correlated with DSC data. Obtained results allowed to assign 1222 cm⁻¹ band to the deformation vibrations of OH-groups, bounded to the surface adsorbed water molecules by weak hydrogen bonds (5 kcal/mol). During the temperature growth these molecules desorbed, which also resulted in the intensity decreasing of stretching OH-groups vibration IR-bands at 3420 cm⁻¹. The destruction and desorption of surface water complexes led to Ti–O–H bond strengthening. IR bands at 1137 and 1048 cm⁻¹ were attributed to the stronger bounded adsorbed water molecules, which are also characterized with stretching OH-groups vibration bands at 3200 cm⁻¹. These surface structure were additionally stabilized by hydrogen bonds with the neighbouring TiO₂ lattice anions and other OH-groups, and desorbed at higher temperatures.     

Spectrophotometric phosphate determination in urine by ligand exchange extraction

A new spectrophotometric method for the determination of phosphate in urine is proposed, based on the ligand exchange extraction produced by phosphate solution at pH 7.5 when it is shaken with a solution of Fe(III) indole-2-carboxylate iniso-amyl alcohol. The organic layer decoloration is measured at 400 nm and the phosphate indirectly determined. The sensitivity of the method is 1.07 × 10³ 1 mol^–1 cm^–1, the linear working range 1–15 × 10^–5 mol/l of phosphate and the relative standard deviation 5%. It does not require previous treatment of the sample and it is free from interferences by other normal or pathological constituents of the urine samples. The results agreed closely with those obtained by using a Sigma Diagnostics procedure for inorganic phosphorus, based on the Fiske-SubbaRow method. The method does not require special instrumentation and is not expensive.     

Enhanced Static Modulated Fourier Transform Spectrometer for Fast Approximation in Field Application

We discuss the data sampling frequency, the spectral resolution, and the limit for non-aliasing in the static modulated Fourier transform spectrometer based on a modified Sagnac interferometer. The measurement was performed in a very short 4 ms, which is applicable for real time field operation. The improved spectrometer characteristics were used to investigate the spectral properties of an InGaAs light emitting diode. In addition, The measured spectral peak was shifted from 6420 cm⁻¹ to 6365 cm⁻¹, as the temperature increased from 25 °C to 40 °C, when the operating current is fixed to be 0.55 A. As the applied current increased from 0.30 A to 0.55 A at room temperature, the spectral width was broadened from 316 cm⁻¹ to 384 cm⁻¹. Compared to the conventional Fourier transform spectrometer, the measured spectral width by the static modulated Fourier transform spectrometer showed a deviation less than 10%, and the spectral peak shift according to the temperature rise showed a difference within 2%.     

Far-infrared spectrum,barrier to internal rotation,ro structure,and ab initio calculations for acetylacetylene

The far-infrared spectrum has been recorded from 50 to 360 cm^–1 at a resolution of 0.10 cm^–1 for acetyiacetylene (1-butyne-3-one], CH₃C(O)CCH. The fundamental methyl torsion has been observed at 117.94 cm^–1, from which a periodic barrier to internal rotation has been calculated to be 346 cm^–1 (989 cal mol^–1]. Infrared spectra (3500-50 cm^–1] of the gas and solid and the Raman spectra (3500-100 cm^–1) of the gas, liquid, and solid are reported. Utilizing previously reported rotational constants for three isotopic species,r _o structural parameters have been determined for the heavy-atom skeleton. The fundamental vibrational frequencies, barrier to internal rotation, and structural parameters that have been obtained experimentally are compared to those obtained from ab initio Hartree-Fock calculations employing 3-21G, 6-31G, and DZ basis sets and to the corresponding quantities for some similar molecules.     

Construction of a universal model for non-invasive identification of penicillins for injection using near-infrared diffuse reflectance spectroscopy

A universal NIR model for identification of 24 types of penicillins for injection has been developed. A total of 194 batches of 24 products from 87 manufacturers in China were used in the study. The classification model is a principal component analysis (PCA) based model consisting of a primary identification library with four sub-libraries. The spectral frequency regions used were 6000–6400 cm⁻¹ and 8400–8900 cm⁻¹ in the main library, 6000–6800 cm⁻¹ in sub-library 1, 4100–12,000 cm⁻¹ in sub-libraries 2 and 3, and 6200–6400 cm⁻¹ and 4700–5000 cm⁻¹ in sub-library 4. The data preprocessing method is the first derivative with nine-point smoothing followed by vector normalization. The distances between spectra were calculated using factors 2–5 for the primary identification library, factors 4–7 for sub-library 1, and factor 2 for sub-libraries 2–4. The specificity of the model was validated, and it had a correct identification rate of approximately 99%. This study has not only confirmed, but also improved the strategy described in our early report (Chong et al. (2009) [11]) to build such a library for the identification of different medicines by NIR.     

In-situ FT-IR studies on cyclic voltammetry of polythiophene

In-situ FT-IR spectra were taken during a cyclic voltammetric study of polythiophene in 1M LiClO₄ in propylene carbonate. The external reflection technique was used in the spectroscopic measurements. A broad band extending from 1500 cm^–1 to higher wave numbers appeared during oxidation of polythiophene with a potential scan from 2.8 V to 4.2 V. Bands due to doping of the polymer at 1330 and 1020 cm^–1 were also found to increase during the same potential scan. The appearance of spectral changes above 3.3 V supports the model of two types of doping processes occurring in the polymer. The observed changes almost disappeared during the reverse scan.     

UV-Visible and IR Spectroelectrochemical Studies of FeVO4 Sol-Gel Films for Electrochromic Applications

The sol-gel synthesis route, in combination with dip-coating deposition, was used for the preparation of FeVO₄ films. TEM measurements of Fe/V (1 : 1)-oxide films heated at 400°C reveal that the films consist of a triclinic FeVO₄-I and an orthorhombic FeVO₄-II phases with a grain size of up to 50 nm. The electrochromic properties of the films were tested in 1 M LiClO₄/propylene carbonate (PC) using various electrochemical techniques and in-situ UV-visible spectroelectrochemical measurements. The best compromise between the charge capacity per film thickness (Qd^–1 = –0.14 mC cm^–2 nm^–1), electrochemical stability (>1000 cycles) and optical modulation (T_vis = 0.15) was achieved in the potential range of 4.80 to 1.80 V vs. Li, which suggests that FeVO₄ films can be used as counter-electrodes in electrochromic devices.Extensive IR-spectroscopy studies of FeVO₄ films in charged/discharged states revealed the following spectra changes: (i) small charging (–0.01 mC cm^–2 nm^–1) leads to a variation in the intensity of all the vibrational bands without shifting their frequencies, (ii) higher chargings bring about the intensity and frequency changes of bridging V—O···Fe and V···O···Fe stretchings showing that vanadium, and probably also iron, are involved in the insertion/extraction processes, (iii) below 500 cm^–1 broad absorption appears due to the Li⁺—O modes, which also remained in the IR spectra of discharged (bleached) states revealing the irreversible lithiation, and (iv) charging to –0.30 and –0.50 mC cm^–2 nm^–1 leads to the amorphisation of the film structure.     

Application of symmetry coupling coefficients in the evaluation of the electronic spectra of d 7 ions

The optical absorption spectrum of cobalt chloride thiourea has been studied at room and liquid air temperatures. The results have been interpreted using group theoretical methods taking into account all the quartet states and several doublet states. Crystal field, electrostatic, and spin-orbit coupling interactions were included to yield the allowed transitions with the relative transition probabilities. The experimental results were interpreted for the following set of parameters: B = 750cm^–1, C = 3100cm^–1, = 7370cm^–1, = -200 cm^–1, = 500cm^–1, and = 450 cm^–1.     

Determination of ultra-trace levels of gold in size-segregated atmospheric particulate samples by laser induced fluorescence: towards an aerosol tracer

A method is described for measuring the gold content of integral and size-segregated samples of atmospheric particulate matter. After acid digestion and a liquid/ liquid extraction, the sample are analysed by Two-Colour Laser Induced Fluorescence in a graphite furnace. An absolute instrumental detection limit of 1 fg is achieved. Assuming a sampled volume of 1 m³, this corresponds to an atmospheric concentration of 50 fg m^–3. Due to blank limited noise, the above limits increase to 20 fg and 1 pg m^–3, respectively. Results of the analysis of filter samples as well as of size-segregated impactor samples are presented.     

Separation and determination of uranium(VI) with calixarene hydroxamic acids

A new calixarene hydroxamic acid, 5,11,17,23-tetra-(N-p-chlorophenyl hydroxamate c-phenyl-25,26,27,28-tetrahydroxycalix[4]arene (CPCHA) was synthesized and used for the extraction and spectrophotometric determination of uranium(VI). The molar absorptivity of the uranium(VI)-CPCHA-thiocyanate complex was 9.9·10³ 1·mol^–1·cm^–1 at 436 nm. The system obeyed Beer's law in the range of 1.78–23.1 ppm of uranium. The uranium(VI)-hydroxamate-ethyl acetate complex was directly aspirated for graphite furnace atomic absorption spectrometry measurements (GFAAS) which increased the sensitivity by about a factor of fifty. Uranium was determined in various standard and environmental samples.     

Atomic absorption spectrometric determination of indium in gallium arsenide

Summary The determination of indium in heavily doped gallium arsenide (0.2–1.2 mg g^–1 In), by both electrothermal and flame AAS is reported. The sample is first decomposed with nitric acid and the diluted solution is atomized by employing the more convenient technique. The conventional air-acetylene flame is used for samples containing at least 1 mg g^–1 indium. For lower concentrations the electrothermal atomization is required and matrix-matched standards become necessary. Platform sampling is shown to improve both sensitivity and repeatability in comparison with the tube-well sampling. Dependence of the matrix effect on both the signal measurement mode and deterioration of the platform is examined. By increasing the sample mass up to 100 mg, without further dilution of the solution to be injected into the furnace but with the optical correction of the background, a detection limit (6 s) of 4.2 ng g^–1 (1.2×10¹⁴ atoms cm^–3) is achieved. The method was applied to In doped GaAs samples and the results are compared with those independently obtained by differential pulse polarography.

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AAS-Bestimmung von Indium in Galliumarsenid

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This work was presented at the Euroanalysis VI Conference (Paris, September 7–11, 1987)     

Study of a hollow cathode arc discharge in the presence of chromium oxide

A hollow cathode arc discharge in hydrogen has been used for the purpose of chromium oxide reduction, the solid oxide being placed inside the anode. Mass transport from the oxide to the gas phase and excitation conditions in the plasma have been investigated. The results show that a substantial amount of oxide is transferred to the gas phase with subsequent reduction and deposition inside the cathode cavity, in the form of a pure metal. The residual part condenses on the discharge chamber wall as an amorphous substance, containing 50–60% of Cr metal, and on the anode surface under the form of a mixture of chromium oxide and metal crystals (10%). From spectroscopic investigations it follows that, inside the anode zone, total Cr concentration in the gas phase is of the order of 10¹⁴ cm^–3, the excitation temperature of the atoms and ions being 4500 and 5500 K, respectively, and the ionization temperature being about 6000 K.Notation I absolute spectral line intensity (W cm^–2 sr^–1) - emission coefficient (W cm^–3 sr^–1) - A relative absorption - absorption coefficient (cm^–1) - L plasma diameter (mm) - f _tk oscillator strength - _D full Doppler width (cm^–1) - S( ₀ L) Ladenburg-Levy function - wave number (cm^–1) - k _pl mass transport rate (mol cm^–2 s^–1) - k _th thermal reduction rate (mol cm^–2 s^–1) - u ion mobility (mm V^–1 s^–1 ) - E electric field strength (V mm^–1) - drift velocity (cm s^–1)     

Über dieIR-Spektren der dinegativen Ionen einiger polycyclischer Mononitrile und Elektronenübergänge zwischen dinegativen Ionen und neutralen Molekülen

Zusammenfassung Die Nitrilgruppe in den dinegativen Ionen (DA) des mit metall. K in Tetrahydrofuran (THF) erhaltenen 1-Cyanpyrens, 9-Cyananthracens, 4-Cyanbiphenyls und 1- und 2-Cyannaphthalins zeigt sehr breite (50–70 cm^–1) und intensive Bandenv _CN zwischen 2020–2070 cm^–1.DieIR-Spektren im Bereich 2000–2250 cm^–1 wurden zur Untersuchung der Elektronenübergänge zwischenDA und einigen neutralen Molekülen herangezogen.

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IR spectra of some dinegative polycyclic mononitrile ions, and electron transitions between the ions and neutral molecules

The CN group in the dinegative ions of 1-pyrenecarbonitrile, 9-anthracenecarbonitrile, 4-biphenylcarbonitrile, 1- and 2-naphthalenecarbonitriles, resp., obtained with K in tetrahydrofuran (THF), gave rise to very broad (50–70 cm^–1) and intensive bands in the 2020–2070 cm^–1 region.IR spectra in the 2000–2250 cm^–1 region have been used to study the electronic transitions between dinegative ions and some neutral molecules.

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Mit 3 Abbildungen     

A new polymeric chromogenic reagent for dual-wavelength spectrophotometric determination of iron(III)

By condensing chitosan with 7-(4-formyl-phenylazo)-8-quinolinol-5-sulfonic acid (FPAQS), a new polymeric chromogenic reagent C-FPAQS has been synthesized and its properties investigated. In acidic media (pH 2.7), C-FPAQS reacts with iron(III) to yield an orange complex with a molar absorptivity of 2.8 × 10⁴ lmol^–1 cm^–1 at 420 nm, and in the meantime a negative peak at 524 nm. The apparent molar absorptivity (420–524 nm) obtained by dual-wavelength measurements is 7.9 × 10⁴lmol^–1cm^–1 which is about two times higher than that by single-wavelength measurements at 420 nm Beer's law is obeyed in the range of 0–0.8 g ml^–1 for iron(III). The developed method has been satisfactorily used to determine iron at the 0.03 to 3% (ww) level in a nylon-6 and in a soil sample. Compared to the corresponding low-molecular weight FPAQS and other chromogenic reagents, C-FPAQS has not only good sensitivity but also largely increased acid solubility and improved selectivity for iron, which may be explained by the incorporation of FPAQS into an acid-soluble polymer.     

Studies on the structure of the urea-orthoboric acid complex

Thermal and infrared spectral studies of the urea-orthoboric acid complex are reported. The complex is formed through the elimination of 0.5 H₂O molecule. Infrared spectral data show the presence of hydrogen-bonding and the force constant calculated for the N ... HO bond is found to be 4–5×10^–5 dyne cm^–1, which is for the order of a single bond and indicates strong hydrogen-bonding in the complex. A tentative structure for the complex is proposed.     

Raman and Infrared Spectra, Ab Initio Calculations, Normal Coordinate Analysis, and Conformational Stability of 2-Methoxypropene

The Raman (3500–40 cm^–1) and infrared (3500–70 cm^–1) spectra of gaseous and solid 2-methoxypropene, CH₃O(CH₃)C=CH₂, and the isotopomers, CD₃O(CH₃)C=CH₂ and CH₃O(CD₃)C=CD₂ have been recorded. In addition, the Raman spectra of the liquids have been recorded with qualitative depolarization measurements. All of these data indicate that only one conformer is present in the fluid phases at ambient temperature and this form is the cis conformer, which remains in the solid. Assignments are provided for the fundamentals of all three isotopomers for the cis conformer with C_s symmetry. The far-infrared spectra of all three isotopic species have been recorded at a resolution of 0.1 cm^–1 in the gas and 1.0 cm^–1 in the solid. The parameters of the potential function governing the asymmetric torsion are determined to be V₃ = 1485 ± 9 cm^–1 and V₆ = –55 ± 4 cm^–1 for the d₀ compound, where only two terms were determined, since a second conformer was not evident. The barrier to internal rotation for the methyl group attached to the oxygen atom is 1370 ± 8 cm^–1 and the C—CH₃ barrier is 772 ± 5 cm^–1. Ab initio calculations with full electron correlation have been carried out by the perturbation method to second order to obtain the equilibrium structural parameters, harmonic force constants, fundamental frequencies, infrared intensities, Raman activities, depolarization values, and conformational stability. The predicted values have been compared to the experimental values where appropriate.     

Far infrared spectrum,conformational stability,barriers to internal rotation,vibrational assignment,and ab initio calculations of 2-chloro-3-fluoropropene

The far infrared spectrum (375 to 30 cm^–1) of gaseous 2-chloro-3-fluoropropene, CH₂=C(CH₂F)CI, has been recorded at a resolution of 0.10 cm^–1. The fundamental asymmetric torsional mode is observed at 117.5 cm^–1 with ten excited states falling to low frequency for thes-cis (fluorine atom eclipsing the double bond) conformer. For the higher energy gauche conformer, the asymmetric torsion is estimated to be at 94 cm^–1. From these data the asymmetric torsional potential function has been calculated. The potential function coefficients are calculated to be in cm^–1):V ₁=803±21,V ₂=–94±21,V ₃= 1025±10,V ₄=95±10, andV ₆=2±1, with an enthalpy difference between the more stables-cis and gauche conformera of 550±100 cm^–1 (1.57±0.29 kcal/mol). This function gives values of 1227±50cm^–1(3.51±0.14kcal/mol), 1266±200 cm^–1 (3.62±0.57 kcal/mol), and 665±100 cm^–1 (1.90±0.29 kcal/mol), for thes-cis to gauche, gauche to gauche, and gauche tos-cis barriers, respectively. From the relative intensities of the Raman lines of the gas at 652 cm^–1 (gauche) and 731 cm^–1 (s-cis) as a function temperature, the enthalpy difference is found to be 565±96 cm^–1 (1.62±0.27 kcal/mol). However, the more polar gauche conformer remains in the crystalline solid. The Raman spectrum of the gas has been recorded from 3500 to 70 cm^–1 and, utilizing these data and the previously reported infrared data, a complete vibrational analysis is proposed for both conformers. The conformational stability, barriers to internal rotation, fundamental vibrational frequencies, and structural parameters that have been determined experimentally are compared to those obtained from ab initio Hartree-Fock gradient calculations employing both the 3–21 G^* and 6–31G^* basis sets and to the corresponding quantities for some similar molecules.