Journal of Applied Spectroscopy最新文献

Developments of molecular resolution spectroscopy have been key in environmental sensing, where the specificity and accuracy of analysis of the molecules in the atmosphere have been identified with high precision. An experimental analysis of the uses of molecular spectroscopy for the detection and measurement of minor compounds, emissions, and other climatic occurrences is discussed. Thanks to the analysis of changes in the spectra of different molecules, the environmental conditions and evaluation of the dynamics of pollutants with high accuracy is also possible. To track carbon dioxide, methane, nitrous oxide, and other greenhouse gases, aerosols, and toxic chemicals, we have carried out experiments with Fourier-transform infrared spectroscopy, cavity ring-down spectroscopy, and laserinduced fluorescence. It is also demonstrated that the integration of these technologies with drone-based remote sensing is being tested to explore new ways for real-time global environment monitoring. This paper shows how high-resolution spectroscopy revolutionized environmental studies have given policy-makers essential information on sustainable environment management.

Tadalafil and alfuzosin hydrochloride are frequently used together to treat benign prostatic hyperplasia. Recent approved combination of these medications was selected because only one study has investigated their synthetic mixture, and no research has examined the pharmaceutical dosage form using UV analysis. The purpose of this study is to create and verify a green UV spectrophotometric technique for the simultaneous measurement of tadalafil and alfuzosin hydrochloride in their combination dose form by developing two methods to ensure the lowest environmental impact, i.e., absorption correction method (method A) and the simultaneous equation method (method B). Tadalafil exhibited zero absorbance at 340 nm in method A, whereas alfuzosin hydrochloride exhibited absorption at 290 and 340 nm. Absorption maxima of 244 nm for alfuzosin hydrochloride and 283 nm for tadalafil are used in method B. A linear relationship in method A was found with correlation coefficient value of 0.999 for alfuzosin hydrochloride and 0.999 for tadalafil. While in method B, correlation coefficient of 0.999 and 0.996, respectively. All the validation parameters for the developed methods were found to be within the ICH guidelines' limits. The developed UV spectrophotometric method received an AGREEprep score of 0.81, MoGAPI score of 77 and BAGI score of 72.5. For routine quality monitoring of alfuzosin hydrochloride and tadalafil, this approach offers a straightforward, affordable, and environmentally friendly substitute that preserves analytical performance while promoting sustainable pharmaceutical analysis. If successfully implemented, it can help labs lessen their environmental impact without compromising the accuracy of their analyses.

The effect of UV-irradiated phosphatidylcholine (or oleic acid) on a number of heme-containing proteins (human hemoglobin, equine myoglobin, horseradish peroxidase, and bovine cytochrome C) manifested as the development of a differential spectrum in the Soret band (ΔD) during their interaction that was found to be characteristic for hemoproteins of both animal and plant origin based on an analysis of spectral changes in the 403–423 nm wavelength range. It was shown that the intensity of the spectral response under the specified conditions was distributed in the following order: peroxidase ≥ myoglobin ≥ hemoglobin ≥ cytochrome C. The determination of peroxidase as the best indicator for the detection of peroxidized lipids by a spectroscopic method can be used while conducting clinical and biochemical studies involving it and for developing new methods of diagnosing the body's ability to protect against oxidative stress and predicting its ability to recover from diseases of varying severity.

Peculiarities of acousto-optical modulation of annular light beams with the wavelength of 532 nm on longitudinal ultrasound waves in paratellurite crystals are theoretically and experimentally investigated. The dependence of the diffraction efficiency of annular beams on the acousto-optical interaction length and ultrasound power is calculated using the two-dimensional coupled wave theory. The bandwidth of modulator frequency tuning on annular beams of ~42–45 MHz is achieved at the level of 3 dB for a central ultrasound frequency of 100 MHz. It is shown that the bandwidth differs insignificantly for an incident light beam of annular and Gaussian shape.

Alumina (Al₂O₃) added to the cryolite (Na₃AlF₆) melt in an electrolysis bath to produce metallic aluminum often partially remains in the melt and leads to an increase in energy costs. Therefore, monitoring the aluminum oxide content in cryolite is an important analytical task in aluminum production. The present paper proposed using bands of the aluminum monoxide AlO green system to estimate the alumina content in cryolites using laser-induced breakdown spectroscopy. For this, a series of samples of the NaF–Na₃AlF₆–Al₂O₃ system with a constant cryolite ratio (1.7) were used. It was found that focusing the radiation below the sample surface by a depth of 3–6 mm provided the minimum RSDs (4–8% for the 0–0 band and 6–10% for the 1–1 band) and the maximum signal-tobackground ratio (80–120 for the 0–0 band and 40–75 for the 1–1 band) in the time window of 4–16 μs after the laser pulse. The selected focusing and time window conditions made it possible to detect a dependence between the intensities of the 0–0 and 1–1 bands of AlO and the alumina content, which was characterized by a high background and relatively low sensitivity. Normalization to the background allowed this dependence to be used for qualitative separation of cryolite systems with high and low alumina contents.

Single-bubble sonoluminescence spectra were recorded in the mode of a bubble moving near the center of levitation in a liquid for the analysis of water samples contaminated with commercial gasoline. These spectra contained characteristic bands of emitters representing gasoline components, i.e., xylenes, terphenyls, anthracene, and C₂ as a decomposition product of other gasoline components (namely benzene, pentane, and hexane) in the bubble plasma. Recording the bands of these emitters against the background of the spectral continuum of water sonoluminescence allowed gasoline in water to be determined from the strongest band of terphenyls as a function of the amount of gasoline. A relationship between the intensity of this band and the amount of gasoline in water was constructed. The experimental data obtained in this work can be used to detect and determine gasoline polluting water.

The freshness of pork is a critical factor in determining its quality and value, impacting its economic worth and suitability for consumption. Near-infrared spectroscopy was employed to collect the spectra of pork from day 1 to 9 at 18 ± 2°C. The backpropagation neural network (BPNN) algorithm, in conjunction with the previously mentioned near-infrared (NIR) spectral data, was utilized to construct a predictive model for the assessment of pork freshness, with the duration of storage serving as the primary variable. The model was evaluated in comparison to more traditional approaches, including partial least squares (PLS) and random forest (RF) models. The experimental results demonstrated that the BPNN model exhibited the most optimal test performance, with a determination coeffi cient (R²) of 0.93; the root-mean-square error of prediction (RMSEP) was 0.62 days. Furthermore, the mean absolute error of the test set (MAE) for the BPNN model was 0.48 days, indicating satisfactory prediction results. The experimental data demonstrated the feasibility of the proposed method in accurately estimating pork freshness, thus providing a novel technological reference for meat detection.

The electronic structure and binding energy of adducts and ternary systems of carboplatin, aminolevulinic acid, and fullerenol, both hydrogen-bonded and ester-bonded bioconjugates, were studied using the HF-3c/MINIS/def2-SV(P)/ECP(Pt) quantum-chemical modeling method considering intermolecular interactions and the ORCA 5.03 software package. An analysis of the total energies of the systems and the calculated energy diagrams of the highest occupied and lowest unoccupied molecular orbitals of both the starting components and the molecular assemblies formed by them allowed conclusions to be drawn regarding the most likely stable combinations. Synergistic eff ects of the three-component system carboplatin–aminolevulinic-acid–fullerenol-C₆₀(OH)₂₄ were identifi ed. Potential applications for chemotherapy in oncology were outlined.

The possibility of employing a method for determining the pure electronic transition (E₀₀) in molecular electronic spectra using the quantum fluctuation theorem (QFT) with perturbations decreasing the elementary transition intensity and acting as its screening is considered. For this, a screening coefficient, i.e., a coefficient for decreasing the spectral intensity because of screening to a value satisfying the QFT, is introduced into the main QFT relation for the electronic transition. Examples of molecular electronic spectra from the visible, UV, and x-ray regions are used to show that introduction of a screening coefficient brings the spectrum into conformity with QFT conditions and, consequently, with the conditions for determining the pure electronic transition using it. E₀₀ in the proposed model is shown to depend on the screening coefficient, with E₀₀ closest to the true value corresponding to the lowest screening coefficient.

The ultrasound-induced nucleation and growth of molybdenum, vanadium, and hydrated tungsten oxide particles in aqueous solutions of the corresponding oxo-acids have been studied by dynamic light scattering. The sono-induced polycondensation of oxo-anions can be catalyzed by nickel and iron through a redox mechanism, which permits the generation of medium-size monodispersed oxide particles varying in diameter from 2 to 526 nm for MoO₃, 15 to 664 nm for V₂O₅, and from 40 to 1098 nm for WO₃ depending on the ultrasound exposure dose.