Derayea, Sayed M.Madian, HodaSamir, EbtihalHamad, Ahmed A....
7页
查看更多>>摘要：In the present work a new, feasible, and green approach was employed for the analysis of milnacipran. A drug is used in the management of depression in addition to fibromyalgia. It inhibits of the reuptake of two essential neurotransmitters serotonin and nor-adrenaline. In slightly alkaline buffer (pH 8.5) the pri-mary amino group of milnacipran reacted with fluorescamine to give a substituted pyrrolone derivative which exhibited high fluorescence activity. The fluorescence of produced derivative was measured at (lambda(ex) 385 nm, lambda(em) 477 nm), and the experimental factors were cautiously optimized. The measured intensity of fluorescence was plotted versus the respective concentration of milnacipran to setup the calibration plot which has a linear concentration range of 50-300 ng/mL. The ICH guidelines were utilized to totally validate the presented approach. In addition the method could be efficiently incorporated in the analysis of commercial milnacipram tablets with no considerable effect on the results of the assay for milnacipran. The developed approach is characterized by its high simplicity and greenness of the procedure which make it suitable for routine analysis. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In the previous work, the SiBr+ cation is suggested as a candidate molecule for laser cooling, and in this work, on the basis of high-level ab initio calculation, the possibility of SiBr+ cation laser cooling is studied by considering the core-valence electrons correlations and spin-orbit coupling (SOC) effect. The potential energy curves of 12 lambda-S states and 36 omega states considering SOC were obtained by using the multi reference configuration interaction method and Davidson correction. Our computed results show that the Franck-Condon factor f(00) for SiBr+ is only 0.619, which cannot guarantee that the number of the leaked photons is enough small, and more pumping laser beams are needed. Based on the calculated molecular properties, we discuss in detail the feasibility of laser cooling of SiBr+ and the results indicate that it is a challenge for laser cooling of SiBr+. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Histamine (His) is used as an indicator of seafood quality, but it can be toxic at high intakes. A fluorescence (FL)-surface-enhanced Raman scattering (SERS) dual-mode assay system has been developed for His detection. The His detection method was established based on the specific binding capacity of gold nanoparticles (AuNPs) for the FL derivative of His and o-phthalaldehyde (OPA). In this strategy, His reacted with the OPA to form a Schiff base product (O-His) along with a change in FL and SERS activities. The usual nature of AuNPs could display a significant role both enhancement of SERS and quenching of FL signals. The current investigation displayed a good selectivity toward His over all other biogenic amines. Under the optimized analytical conditions, the SERS and FL intensity of the system were linearly proportional to the His concentration in the range of 0.05-4.5 mg/L and 1-20 mg/L with a detection limit of 0.04 mg/L and 0.32 mg/L, respectively. Moreover, the proposed method was successfully applied for His determination in seafood with promising results. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Accurately evaluating the aging state of oil paper insulation in electrical equipment is a key to ensure the safe operation of the power transformer. For achieving highly sensitive in-situ detection of dissolved furfural in transformer oil with good reproducibility, flower-like silver nanoparticles modified with carbon nanotubes (CNTs@Ag-F-AgNPs) was synthesized by a combination of electroless silver plating and redox method. The large specific surface area and strong adsorption capacity of CNTs@Ag promoted the formation of more "hot spots ". CNTs@Ag-F-AgNPs were adsorbed on Si-Au substrate via mercapto groups on the coupling agent 1'4 phenyldimercaptan molecule (BDT). Using rhodamine 6G (R6G) as probe molecule, the enhanced factor reached 6.96 x 10(9). Then, the substrate was used for in-situ SERS detection of transformer oil-dissolved furfural at different concentrations and the detection limit was 2.25 mg/L at 1703 cm(-1) (Stretching vibration of C = O in furfural molecule), fulfilling requirements of furfural content detection after severe aging of transformer (4 mg/L). Besides, the relative standard deviation (RSD) of characteristic peak intensity at ten different positions was only 1.74%. These results exhibite that three-dimensional nanostructure with high sensitivity and good reproducibility exhibited a wide application range for in situ detection of dissolved trace furfural in transformer oil. (C) 2022 Elsevier B.V. All rights reserved.
Saleh, Sarah S. S.Lotfy, Hayam M. M.Tiris, GizemErk, Nevin...
10页
查看更多>>摘要：HIAM technique allows the extraction of the original constant signal of each single component out of interference signals of a mixture and further transformed into basic spectrum (D-0). It includes the methods: ratio subtraction coupled with unified constant subtraction (RS-UCS), constant center (CC) and constant extraction (CE). The technique was introduced for the analysis of two pharmaceutical formulations used to treat cardiovascular diseases. The formulations are binary combinations of Amlodipine (AML) with either Atorvastatin (ATR) or Candesartan (CND) which shows interefernce absorbance signals. The technique was valid over the linearity range of (5.0-35.0 mu g/ml) for AML, ATR and CND with recovery percentage 100.40 +/- 1.88 ,100.00 +/- 0.86 and 99.83 +/- 1.07, respectively . The extracted signals were tested for its purity by spectral contrast angle (cos theta) to illustrate the efficency of the HIAM technique where cos theta values ranges from (0.9902 to 0.9986). The presented technique was fully validated regarding ICH guidelines and were statistically compared using one-way ANOVA at 95% confidence. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In order to better understand the bioavailability, toxicity, migration and transformation behaviors of trace metals in river estuary, this study deeply investigated the interactions between organic matters in sediments and trace metals. The results suggested that both protein-like molecules and marine humic acids could react with trace metals (Cu2+ and Cd2+). These two fluorescent substances fixed trace metals through carboxyl group, hydroxyl group, and phenol hydroxyl group, and protein-like molecules were more sensitive than marine humic acids. Moreover, Cu2+ possessed stronger binding ability and more active sites with both protein-like molecules and marine humic acids. Hence, Cd2+ exhibited higher environmental risks due to the higher migration and transformation. The thermodynamic results revealed that the reaction between WEOM and trace metals was spontaneous and exothermic, and low temperature was favorable for immobilization of Cu2+ or Cd2+.This study could help to understand environmental behaviors and impact of trace metals on the sediments of Yangtze River estuary. (C) 2022 Elsevier B.V. All rights reserved.
Augusto de Castro, Pedro ArthurDias, Derly Augustodel-Valle, MatheusVeloso, Marcelo Noronha...
7页
查看更多>>摘要：The health care application of ionizing radiation has expanded worldwide during the last several decades. While the health impacts of ionizing radiation improved patient care, inaccurate handling of radiation technology is more prone to potential health risks. Therefore, the present study characterizes the bone dose response using bovine femurs from a slaughterhouse. The gamma irradiation was designed into low-doses (0.002, 0.004 and 0.007 kGy) and high-doses (1, 10, 15, 25, 35, 50 and 60 kGy), all samples received independent doses. The combination of FTIR spectroscopy and PLS-DA allows the detection of differences in the control group and the ionizing dose, as well as distinguishing between high and low radiation doses. In this way, our findings contribute to future studies of the dose response to track ionizing radiation effects on biological systems. (C) 2022 Published by Elsevier B.V.
de Matos, Caroline S.Petersen, Philippe A. D.Constantino, Vera R. L.Magri, Vagner R. R....
13页
查看更多>>摘要：Folic acid (FA; vitamin B9) and its associated sodium salts, strongly relevant for many scientific and technological applications from nutrition to pharmacology and nanomedicine, suffer from a lack of characterization combining experimental and theoretical. In this work, a spectroscopic investigation of FA and its synthesized sodium salts in the form of dianion (Na2HFol) or trianion (Na(3)Fol) was scrutinized in their solid state. The spectroscopic (infrared, Raman, and solid state C-13-nuclear magnetic resonance) data interpretation was supported by theoretical calculations using the Density Functional Theory (DFT). Additionally, the compounds were characterized by UV-VIS diffuse-reflectance spectroscopy, combined thermal analysis (TG/DTG-DSC) coupled to mass spectrometry, and X-ray diffractometry. The main signatures of each species were identified, as well as the influence of the protonation level on their physicochemical properties. These distinct properties for the three compounds are mainly based on signals assigned to glutamic acid (glutamate) and pterin (neutral or anionic) moieties. This work should help developing new products based on FA or its anionic forms, such as theragnostic/drug delivery systems, supramolecular structures, nanocarbons, or metal complexes. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：This study is concerned with assessing the bulk and tablet dosage forms of Dolutegravir (DTG) by means of a novel yet simple environmentally friendly spectrofluorimetric method that features fast response and high sensitivity compared to the time consuming HPLC methods and the lower sensitivity spectrophotometric ones. The method relies mainly on measuring the native fluorescence of Dolutegravir in water at an emission of 415 nm after excitation at 262 nm. The method shows rectilinear fluorescence-concentration relation over Dolutegravir concentration range of 0.2-1.2 mu g/mL at the emission maxima, with detection limit of 0.020 mu g/mL and quantification limit of 0.061 mu g/mL. The results of the proposed method were compared with those obtained by applying the comparison method and the two sets coincided harmoniously. In addition, the method was validated in accordance with ICH guidelines for linearity, accuracy, precision, specificity, and robustness. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this work, the spectroscopic properties of scutellarein (6-hydroxyapigenin) were studied in three organic solvents (methanol, acetonitrile and N,N-dimethylformamide) taking into account possible ionization and isomerization (tautomerization) processes. Significant visible colour changes were reported in the case of scutellarein in N,N-dimethylformamide. It was shown that isomerization processes can be one of the reasons for the observed changes in absorption spectrum, because some scutellarein isomers have an absorption band at about 623 nm while other forms of scutellarein show no absorption in this region. Moreover, spectroscopic properties were studied for cases of scutellarein in acetonitrile and methanol. The molar extinction coefficient has been found in the case of methanol solution which could be used to determine scutellarein concentration in this solvent using spectroscopic methods in future studies. The quantum-chemical calculations were performed for neutral and anionic forms and for two types of possible isomers of scutellarein in each solvent. The results help explain the experimentally observed rising absorption in the 500-750 nm wavelength range. Another important result of the quantum-chemical calculations is a prediction of excited state intramolecular proton transfer (ESIPT) in scutellarein. This result has been obtained for free molecule in vacuum and in the cases of methanol, acetonitrile and N, N-dimethylformamide solution. It was found that the excited state energy of the normal molecular form is higher than the excited state energy of the tautomer form of scutellarein.(c) 2022 Elsevier B.V. All rights reserved.
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