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Spectrochimica acta
Pergamon
Spectrochimica acta

Pergamon

1386-1425

Spectrochimica acta/Journal Spectrochimica acta
正式出版
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    Effects of azole rings with different chalcogen atoms on ESIPT behavior for benzochalcogenazolyl-substituted hydroxyfluorenes

    Song, LiyingMeng, XuanZhao, JinfengHan, Haiyun...
    11页
    查看更多>>摘要:ESIPT behavior has attracted a lot of eyes of researchers in recent years because of its unique optical properties. Due to its large Stokes shift and double emission fluorescence, white light can be generated in the fluorophore based on the excited state intramolecular proton transfer (ESIPT) principle. The excited state proton transfer behavior of hydroxylated benzoxazole (BO-OH), benzothiazole (BS-OH) and benzoselenazole (BSe-OH) have been investigated in heptane, chloroform and DMF solvents. By comparing the infrared vibration spectra and the variation of bond parameters from the S-0 to S-1 states, and analyzing the frontier molecular orbitals, the influence of hydrogen bond dynamics, the solvent polarity, charge redistribution and the effects of different proton acceptors on proton transfer were observed. The only structural difference among the three substituted hydroxyfluorenes is the heteroatom in the azole ring (oxygen, sulfur and selenium, respectively). We have scanned the potential energy curve of the ESIPT process, and compared the potential barrier, it is found that the heavier chalcogen atoms are more favorable for proton transfer. At the same time, the potential application of changing heteroatoms in the azole ring by walking down the chalcogenic group in crystal luminescence color regulation is also discussed. (C) 2021 Elsevier B.V. All rights reserved.

    Development of novel univariate and multivariate validated chemometric methods for the analysis of dasatinib, sorafenib, and vandetanib in pure form, dosage forms and biological fluids

    Abdelhameed, Ali S.Attwa, Mohamed W.Attia, Mohamed I.Alanazi, Amer M....
    13页
    查看更多>>摘要:New precise, responsive and selective univariate and multivariate chemometric spectrophotometric methods were developed and validated for determination of vandetanib (VTB), dasatinib (DTB), and sorafenib (SFB) in pure form, tablets, spiked human (plasma and urine). Determination of these drugs is essential because of their therapeutic benefits. These methods included double divisor ratio spectra derivative univariate method and chemometric multivariate method including partial least-squares (PLS) and principal component regression (PCR). A novel univariate method was developed for the estimation of these drugs. This method depends on the UV-Spectrophotometric data for simultaneous analysis of a ternary overlapped mixture. The Double divisor ratio spectra derivative absorption minima at 358.4 nm was used for quantification of VTB, absorption maxima at 300.3 nm for quantification of DTB and absorption maxima at 259.8 nm for quantification of SFB. This method shown a linearity in the extent of 2-9 mu g/mL for VTB and DTB and over the concentration range of 3-9 mu g/mL SFB within correlation coefficient (r2) of 0.9999. This method was successfully applied to pure form, tablet dosage form, spiked human (urine and plasma). Chemometric PLS and PCR models were found to be linear in the range of 2-9, 2-9, and 3-9 mu g/mL for VTB, DTB and SFB, respectively. These models were estimated using eighteen mixtures as calibration set and seven mixtures as validation set. In the original data, the minimum root mean square error of prediction (RMSEP) was 0.11, 0.09 and 0.09 for VTB, DTB and SFB by PLS and 0.05, 0.04 and 0.03 by PCR while in the derivative data, the RMSEP was 0.09, 0.10 and 0.09 by PLS and 0.06, 0.06 and 0.03, by PCR for VTB, DTB and SFB, respectively. These methods were applied for the determination of the drugs in pure form and dosage form. Updating PLS model permitted the determination of the VTB, DTB and SFB in spiked human urine, plasma and drug-dissolution test of their tablet. (C) 2021 Elsevier B.V. All rights reserved.

    The excited state behavior of Group IA alkaline-metal phthalocyanines revealed by photoluminescence and singlet oxygen formation

    Liu, LiminZhang, Xian-Fu
    8页
    查看更多>>摘要:Group IA alkaline-metal phthalocyanine (Pc) complexes (Li2Pc, Na2Pc, K2Pc, Rb2Pc, Cs2Pc) have been synthesized and purified to study their excited state behavior. Their UV-Vis electronic absorption spectra, fluorescence emission and excitation spectra, fluorescence quantum yields and lifetimes, as well as singlet oxygen formation quantum yields have been measured in DMF. These photophysical properties are compared with that of H2Pc. The fluorescence and singlet oxygen formation properties reveal that alkaline metal Pcs show weak heavy atom effect. The results also reveal that alkaline-metal Pcs (Na2Pc, K2Pc, Rb2Pc, and Cs2Pc) show very different excited singlet state (S-1) behavior from that of Li2PC and H2Pc. While S-1 decay of Li2PC is mainly via intersystem crossing and fluorescence, the S-1 decay of M2Pc (M = Na, K, Rb, Cs) is mainly metal ion dissociation: M2Pc(S-1) -> 2M(+) + [Pc](2-)(S-1), in addition to the intersystem crossing. (C) 2021 Elsevier B.V. All rights reserved.

    Turn-on fluorescence ferrous ions detection based on MnO2 nanosheets modified upconverion nanoparticles

    Jiang, MuhanXu, SaiYu, YangGao, Yuefeng...
    8页
    查看更多>>摘要:A turn on upconversion fluorescence probe based on the combination of similar to 32 nm NaYF4: Yb/Tm nanoparticles and MnO2 nanosheets has been established for rapid, sensitive detection of Fe2+ ions levels in aqueous solutions and serum. X-ray diffraction (XRD), transmission electron microscopy (TEM), absorption and emission spectra have been used to characterize the crystal structure, morphology and optical properties of the samples. MnO2 nanosheets on the surface of UCNPs act as a fluorescence quencher, resulting in the quenching of the blue fluorescence (with excitation/emission maximum of 980/476 nm) via fluorescence resonance energy transfer from upconversion nanoparticles to MnO2 nanosheets. With the adding of Fe2+, upconversion fluorescence of the nanocomposites recovers due to the reduction of MnO2 to Mn2+. Because of the low background of the probe offered by upconversion fluorescence, this probe can be used for detecting Fe2+ in aqueous solutions in the range of 0.1-22 mu M with detection limit of 0.113 mu M. The developed method has also been applied to detect 10 mu M Fe2+ ions in serum with recoveries ranging from 97.6 to 105.3% for the five serum samples. Significantly, the probe shows fast response and stable signal, which is beneficial for long-time dynamic sensing. Thus, the proposed strategy holds great potential for disease diagnosis and treatment. (C) 2021 Elsevier B.V. All rights reserved.

    Identification of myocardial fibrosis by ATR-FTIR spectroscopy combined with chemometrics

    Yang, XiaorongWei, XinYu, KaiWan, Changwu...
    8页
    查看更多>>摘要:Different degrees of myocardial fibrosis can often be observed in sudden cardiac death cases, so that the identification of myocardial fibrosis is an important step in forensics to identify cardiac death. Previous methods are restricted by complex algorithms, high cost, low sensitivity and high requirements. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy is an efficient and rapid method to identify tissue types, which has been used increasingly in forensics. This study aims to identify novel biophysical biomarkers of myocardial fibrosis and establish a prediction model by using ATR-FTIR analysis combined with chemometrics. A total of 129 tissue blocks taken from human hearts were cut into slices, and then ATR-FTIR spectroscopy and hematoxylin and eosin (HE) staining were performed. By using HE staining, the samples were divided into the experimental group (with myocardial fibrosis) and the control group (without myocardial fibrosis). The chemometrics classification results showed that the sensitivity and specificity of the training dataset were 0.91 and 1.0 respectively, and the sensitivity and specificity of the predictive dataset were 0.862 and 0.900. This study demonstrated that ATR-FTIR spectroscopy combined with chemometrics is a novel method for identifying myocardial fibrosis. (c) 2021 Elsevier B.V. All rights reserved.

    Improve the precision of platelet spectrum quantitative analysis based on "M plus N" theory

    Li, GangWang, DanZhao, JingZhou, Mei...
    7页
    查看更多>>摘要:Platelets have the functions of promoting blood coagulation and accelerating hemostasis, playing an important role in human body. It is of great medical significance to realize clinical rapid micro detection of platelets by spectral analysis, which is the development direction of clinical detection in the future. However, due to the problem of unobvious characteristic of platelet absorption spectrum, the results of modeling and analysis cannot meet the clinical accuracy requirements. In order to improve the analysis accuracy, based on the "M+N" theory, this paper comprehensively considers the influence of the concentrations of measured component platelet and non-measured component hemoglobin on modeling analysis, and uses the method of selecting training set based on the concentration distribution of two components. At the same time, considering the characteristic of the linear model, the samples at both ends of the concentration of two components are selected as the training set, and the cubic term fitting method is combined to model and predict the concentration of platelet. The following experiments were designed: the training sets were selected by four different methods and used for modeling to predict the platelet concentration, and compared the modeling results of different methods. Through the modeling and prediction of 222 samples, the result showed that the method of selecting the training set with the concentration distribution of two components could effectively improve the prediction accuracy of the established model, and got a better model with better performance, the correlation coefficient Rc reached 0.63, which was 24.98% higher than the result of full modeling for all samples, and RMSE decreased by 10.02%. Considering the influence of non-measured components in modeling is of great significance to improve the prediction accuracy of measured components, and selecting samples from both ends of the concentration values of two components as the training set can further improve the performance and accuracy of the model. (c) 2021 Elsevier B.V. All rights reserved.

    An optosensor based on a hybrid sensing probe of mesoporous carbon and quantum dots embedded in imprinted polymer for ultrasensitive detection of thiamphenicol in milk

    Sa-nguanprang, SurisaPhuruangrat, AnukornBunkoed, Opas
    10页
    查看更多>>摘要:A hybrid fluorescent sensing probe was developed and used to quantitatively analyse thiamphenicol. The probe was constructed by entrapping mesoporous carbon and CdTe*CdS*ZnS quantum dots in molecularly imprinted polymer. The probe was characterized, and the construction and detection conditions were optimized. In the optimized conditions, the recognition sites of the nanoprobe were ultrasensitive and highly selective toward thiamphenicol. The quantitative analysis of thiamphenicol was based on the fluorescence quenching of the hybrid nanoprobe by thiamphenicol. Fluorescence emission was quenched linearly from 0.10 to 100 mu g L-1 with a coefficient of determination (R-2) of 0.9979. The limit of detection was 0.04 mu g L-1. The accuracy of an optosensor based on the hybrid probe was evaluated by analyzing spiked milk samples. The results obtained were compared with the results of high-performance liquid chromatography (HPLC) analysis. The quantitative analysis of the spiked samples with the optosensor agreed well with HPLC analysis. Recoveries were in the range of 93.5 to 100.1 % with good precision (RSD < 5%). The accuracy, speed and convenience of the developed optosensor make it a powerful tool for the detection of thiamphenicol in milk. (C) 2021 Elsevier B.V. All rights reserved.

    Synthesis of gold nanoparticles@reduced porous graphene-modified ITO electrode for spectroelectrochemical detection of SARS-CoV-2 spike protein

    El-Said, Waleed A.Al-Bogami, Abdullah S.Alshitari, Wael
    8页
    查看更多>>摘要:Here, we reported the synthesis of reduced porous graphene oxide (rPGO) decorated with gold nanopar-ticles (Au NPs) to modify the ITO electrode. Then we used this highly uniform Au NPs@rPGO modified ITO electrode as a surface-enhanced Raman spectroscopy-active surface and a working electrode. The uses of the Au nanoparticles and porous graphene enhance the Raman signals and the electrochemical conduc-tivity. COVID-19 protein-based biosensor was developed based on immobilization of anti-COVID-19 anti-bodies onto the modified electrode and its uses as a probe for capturing the COVID-19 protein. The developed biosensor showed the capability of monitoring the COVID-19 protein within a concentration range from 100 nmol/L to 1 pmol/L with a limit of detection (LOD) of 75 fmol/L. Furthermore, COVID-19 protein was detected based on electrochemical techniques within a concentration range from 100 nmol/L to 500 fmol/L that showed a LOD of 39.5 fmol/L. Finally, three concentrations of COVID-19 protein spiked in human serum were investigated. Thus, the present sensor showed high efficiency towards the detection of COVID-19. (c) 2021 Elsevier B.V. All rights reserved.

    Sandwich optoplasmonic hybrid structure for surface enhanced Raman spectroscopy

    Hou, SuxiaWang, JihaoWang, ChenyangYuan, Yuan...
    6页
    查看更多>>摘要:Combined with photonic microstructure and plasmonic nanostructure, the optoplasmonic hybrid structure with fantastic optical properties attracts lots of attentions in recent years. With the help of light enrichment by dielectric photonic microenvironment, the embedded plasmonic nanoantennas generate much greater electromagnetic field enhancement at surface for light harvesting compared to conventional plasmonic nanostructures. In this work, a sandwich optoplasmonic hybrid structure is developed for surface enhanced Raman spectroscopy (SERS) detection, which is consisted of polymethyl methacrylate (PMMA) microspheres array, self-assembled Ag nanoparticles (AgNPs) film and SiO2 microsphere (PMMA@AgNPs@SiO2). The SERS spectra collected on this optoplasmonic substrate point out it has high sensitivity with limit of detection (LOD) at 10 fM. The experimental data demonstrate both the PMMA microarray and SiO2 microsphere play important roles in enrichment of light illuminating at AgNPs for SERS detection, which is confirmed by the simulated electric field distributions. This sandwich optoplasmonic hybrid structure not only enlarges research field of surface plasmon, but also provides a novel SERS subtract for sensitive analysis in chem/bio-field. (C) 2021 Elsevier B.V. All rights reserved.

    Fock-space relativistic coupled cluster study on the RaF molecule promising for the laser cooling

    Osika, YuliyaShundalau, Maksim
    9页
    查看更多>>摘要:The potential energy curves of the ground and five low-lying excited terms of the RaF molecule are calculated using the Fock-space relativistic coupled theory. The electronic term energies, equilibrium inter nuclear distances, transition and permanent dipole moments, sequences of vibrational energies, harmonic vibrational frequencies, Franck-Condon factors, and radiative lifetimes are predicted. The calculated spectroscopic constants are in good agreement with the available theoretical and experimental data. The scheme for the direct laser cooling involving the first excited A(2)Pi(1/2) state is proposed. The data obtained in this study suggests the A(2)Pi(1/2) -> X-2 Sigma(+) channel in the RaF molecule is the almost ideal case for direct laser cooling. It is quite possible that the effective cooling scheme for the RaF molecule can be realized using only one pump laser. (C) 2021 Elsevier B.V. All rights reserved.