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Spectrochimica acta
Pergamon
Spectrochimica acta

Pergamon

1386-1425

Spectrochimica acta/Journal Spectrochimica acta
正式出版
收录年代

    Insight into structural composition of dissolved organic matter in saline-alkali soil by fluorescence spectroscopy coupled with self-organizing map and structural equation modeling

    Liu, DongpingYu, HuibinGao, HongjieLiu, Xueyu...
    9页
    查看更多>>摘要：Soil salinization has been occurring all over the world, which severely affected crop production and threatened the life of mankind. It is necessary to take serious steps to improve soil fertility for the sustainability and productive capacity of agriculture. Soil samples of different depths were collected from native vegetation communities (Comm. Phragmites communis (CPC) and Comm. Populus alba (CPA)) and irrigated crops (corn fields (CFD) and seed melon fields (SMF)) in Hetao irrigation area of China. Three dimensional excitation-emission matrix (EEM) fluorescence technology combined with self-organizing map were used to analyze the dissolved organic matter (DOM) composition and structural characteristics in saline-alkali soils and its spatial distribution under different vegetation covers. Critical factors were recognized by classification and regression tree (CART) for distinguishing soil samples, and latent factors were revealed with structural equation modeling (SEM) for improving the humification degree of DOM from saline soils in Hetao irrigation area. Five components were obtained in the DOM substances, i.e., tyrosine-like (C1), tryptophan-like (C2), UV fulvic-like (C3), visible fulvic-like (C4) and humic-like (C5). The protein-like peaks were all obvious, and the fulvic-like peaks (600-735 a.u.) were conspicuous in the CPC soil than in others, except CFD1 and SMF1. C1 was the critical factor to distinguish native vegetation from irrigated crops, and C1 and C2 were the critical factors to distinguish CFD from SMF. Contrary to the HA/FA (0.20) and A/C (0.25), the path coefficient (-0.15) of sources with T/H was negative, indicating that the incremental contents of fluorenscense substances were in the sequences of protein-like > visible fulvic-like > UV fulvic-like > humic-like, affecting by the allochthonous. C1 (1.00) and C4 (1.00) were the primary components for improving the humification degree of DOM, which were principally originated from plant debris. EEM combined with self-organizing map, CART and SEM is an efficient way to distinguish different salinized soils and reveal the latent factors for improving the soil fertility. (C) 2022 Published by Elsevier B.V.
      原文链接:
    • NSTL
    • Elsevier

    A new zinc-organic framework with 1D channel for constructing a ratiometric Al3+-selective sensor and four inputs INHIBIT logic gate

    Li, QiXu, SijiHe, LiangyuHuang, Kun...
    7页
    查看更多>>摘要：To develop Al3+ fluorescent sensor is significant because the abnormal levels of Al3+ in environment may pose great threat to human body. Herein, a novel metal-organic framework {Zn(Dpada)(Imdba)center dot H2O}(n) (Dpada = 3, 6-di(1H-imidazol-1-yl) pyridazine and Imdba = 2, 2'-iminodibenzoic acid), named Zn-MOF, has been architected with one-dimensional channel under hydrothermal conditions. Zn-MOF exhibits good thermal and solvent stability and can also keep structural integrity over the pH range of 5.0 - 9.0. Fluorescent experiments show that Zn-MOF has high selectivity and sensitivity towards Al3+ via ratiometric fluorescence signal changes (F-470 nm/F-390 nm) and the detection limit is evaluated to be 0.69 mu M. In addition, Zn-MOF performs good recyclability in sensing of Al3+ with at least 5 cycles. Besides, an INHIBIT logic gate has been constructed with chemical ions (Al3+, Cr3+, Fe3+ and Hg2+) as input signals and emission ratio (F-470 nm/F-390 nm) as output signal. Significantly, Zn-MOF can be applied to tracing Al3+ using real water samples, presenting great potential in water quality monitoring application.
      原文链接:
    • NSTL
    • Elsevier

    Selective and sensitive detection of tartrazine in beverages by sulfur quantum dots with high fluorescence quantum yield

    Peng, XiaohuiWang, YaWang, QingyingTang, Jiaojiao...
    8页
    查看更多>>摘要：In this work, sulfur quantum dots (TPA-SQDs) protected by terephthalic acid as a stabilizer were synthesized using a one-pot method. When excited at 310 nm, the synthesized TPA-SQDs solution emitted strong blue fluorescence at 428 nm, and the absolute quantum yield was as high as 85.99%. The proposed SQDs can be used as a fluorescent probe to specifically quench tartrazine (TZ), showing a good linear relationship (R-2 = 0.996) at TZ concentrations of 0.1-20 mu M, with a detection limit of 39 nM. By analysing the fluorescence lifetime, UV-Vis absorption spectrum and zeta potential of the assay system, it can be speculated that the fluorescence quenching mechanism of TZ on TPA-SQDs is the inner filter effect (IFE). The proposed method was applied to the detection of TZ in vitamin water and orange juice, and the results were consistent with the determination results by highperformance liquid chromatography. The recoveries and relative standard deviations were 93.2-102.6% and 1.34-2.88%, respectively, which provided an alternative method for the determination of TZ in beverages or other food samples.
      原文链接:
    • NSTL
    • Elsevier

    High selective spectroelectrochemical biosensor for HCV-RNA detection based on a specific peptide nucleic acid (vol 217, pg 288, 2019)

    El-Said, Waleed A.Choi, Jeong-woo
    1页
      原文链接:
    • NSTL
    • Elsevier

    Olive oil classification with Laser-induced fluorescence (LIF) spectra using 1-dimensional convolutional neural network and dual convolution structure model

    Chen, SiyingDu, XiandaZhao, WenquGuo, Pan...
    8页
    查看更多>>摘要：Laser-induced fluorescence (LIF) spectroscopy is widely used for the analysis and classification of olive oil. This paper proposes the classification of LIF data using a specific 1-dimensional convolutional neural network (1D -CNN) model, which does not require pre-processing steps such as normalisation or denoising and can be flexibly applied to massive data. However, by adding a dual convolution structure (Dual-conv) to the model, the features of the 1-dimensional spectra are more scattered within one convolution-pooling process; thus, the classification effects are improved. The models were validated through an olive oil classification experiment which contained a total of 72,000 sets of LIF spectra data, and the classification accuracy rate reached ~99.69%. Additionally, a common classification approach, the support vector machine (SVM), was utilised for the comparison of the re-sults. The results show that the neural networks perform better than the SVM. The Dual-conv model structure has a faster convergence speed and higher evaluation parameters than those of the 1D-CNN in the same period of iterations, without increasing the data dimension.
      原文链接:
    • NSTL
    • Elsevier

    RhB-encapsulated metal-organic cage as a dual-emission fluorescence sensor for detection of malachite green and glycine

    Wang, Xiao-QingZhang, ManMa, XuehuiYang, Jiandong...
    7页
    查看更多>>摘要：RhB@ZrT-1-OH composite was constructed by introduction of Rhodamine B (RhB) into the cages of zirconiumbased metal-organic cage that had two fluorescence emission peaks at 466 and 612 nm upon excitation at 327 nm. The dual-emission fluorescence sensor exhibits ultra-high sensitive detection for malachite green (MG) and glycine (Gly) in phosphate buffer solution (pH = 6.86). RhB@ZrT-1-OH as a ratiometric fluorescence probe was applied to detect MG with a low LOD of 0.2879 mu M and presented obvious fluorescence visual changes from orange to purple to blue under 254 nm UV-vis lamp. Moreover, RhB@ZrT-1-OH also can be utilized as a "turnon" fluorescence sensor to recognize Gly with a low LOD of 0.3747 mu M and exhibits fluorescence color changes from orange to pink to purple. Notably, the corresponding test papers for sensing MG and Gly were designed for recognize the concentration of MG and Gly. Furthermore, the dual-emission fluorescence sensor can be used to detect MG and Gly in fish and human serum with high sensitivity and reliable. The possible detecting mechanisms of RhB@ZrT-1-OH for sensing MG and Gly were detailedly explored.
      原文链接:
    • NSTL
    • Elsevier

    Intelligent and thermo-responsive Au-pluronic? F127 nanocapsules for Raman-enhancing detection of biomolecules

    Juang, Ruey-ShinWang, Kuan-SyunCheng, Yu-WeiWu, Wei-En...
    6页
    查看更多>>摘要：Thermo-responsive Raman-enhanced nanocapsules were successfully fabricated by Pluronic (R) F127 (F127) decorated with gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) detection of biomolecules. F127 nanocapsules changes from hydrophilicity (swelling) to hydrophobicity (de-swelling) when the temperature increases from 15 degrees C to 37 degrees C, owing to the lower critical solution temperature (LCST) of F127 is about 26.5 degrees C. The size of nanocapsules would be enormous shrinking from 160 nm to 20 nm, resulting in a significant decrease in the distance between AuNPs to enhance hot spot effect, which increases the sensitivity of SERS detection. Based on the thermo-sensitive behavior, the ratio of AuNPs and F127 would be manipulated to find the optimal SERS enhancement effect. SERS nanocapsules can rapidly detect biomolecules (adenine and R6G) with limit of detection (LOD) lower than 10-6 M. In addition, the relatively difficult to detect clinical samples, carboxyl-terminal parathyroid hormone fragments (C-PTH), can also be measured by the thermoresponsive SERS nanocapsules developed in this work. It is expected the biomolecules can be adsorbed at low temperature (15 degrees C), as well as collected and concentrated at high temperature (37 degrees C) for SERS detection, to increase the sensitivity and stability of SERS detection.
      原文链接:
    • NSTL
    • Elsevier

    Spectrophotometric determination of Zr(IV), Hg(II) and U(VI) in solution with their analytical applications: Structural characterization and molecular docking of the solid complexes

    El-Shwiniy, Walaa H.El-Desoky, Sameh I.Alrabie, AliAbd El-wahaab, Badr...
    15页
    查看更多>>摘要：Spectrophotometry was used to determine trace amounts of Zirconium(IV), Mercury(II) and Uranium(VI) in environmental, biological, pharmaceutical and industrial samples. The determination depend on the complexation reactions between albendazole reagent and metal ions [Zr(IV), Hg(II) and U(VI)] at 555 nm, 485 nm and 510 nm, respectively. The experimental conditions were explored to reach the optimum conditions for albendazole-metal ions interaction, including detection of a suitable wavelength, medium (pH), reagent concentration, surfactants effect, reaction time and temperature. Under optimum conditions, the complexes displayed apparent molar absorptivities of 0.8350 x 10(4), 0.6210 x 10(4) and 0.7012 x 10(4) L mol(-1) cm(-1); Sandell's sensitivity of 0.01092, 0.03230 and 0.03394 mu g cm(-2) and with linearity ranges of 1.0-120.0, 3.0-200.0 and 1.0-150.0 mu g mL(-1) for the developed methods, respectively. Furthermore, Elemental analysis, thermal analysis (TGA, DTG), IR, (HNMR)-H-1, spectroscopies, electrical molar conductivity and magnetic moment measurements were used to determine the structures and characteristics of the complexes. A careful examination of the IR spectra revealed that the ligand interacted with all of the metal ions described as a bidentate via the oxygen of the carbonyl of the ester moiety and the nitrogen atom of the heterocyclic -C=N- group. An octahedral geometry for Zr(IV), Hg(II) and U (VI) complexes has been postulated based on magnetic and electronic spectrum data. The band gap values indicated that these complexes were semi-conductors and belong to the same class of extremely effective solar materials. The albendazole ligand and its complexes have been biologically tested against a variety of bacterial and fungal strains, and molecular docking studies have been conducted to evaluate the optimal binding site and its inhibitory action. (C) 2022 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Chemiluminescence of doped carbon dots with H2O2-KMnO4 system for the detection of Cu2+ and tannin

    Yang, YaqiongJiang, YameiWang, XiaoweiHan, Suqin...
    6页
    查看更多>>摘要：The carbon dots doped with chlorine and phosphorus (CDs-Cl,P) were used as chemiluminescence (CL) reagent for the sensitive detection of copper ions (Cu2+) and tannin (TA). The CDs-Cl,P was found to strongly enhance the reaction of H2O2 and KMnO4 in alkaline medium. The enhanced CL behavior of CDs-Cl,P was investigated and it was found that some radicals such as center dot OH, center dot O2- and 1O2 appeared in the CL reaction process. The participation of Cu2+ could result in an enhanced CL intensity of the CDs-Cl,P-H2O2-KMnO4 system due to the Cu2+-catalyzed decomposition of H2O2 resulting in more center dot OH generation. Therefore, the CDs-Cl,P-H2O2-KMnO4 system was used to selectively quantify Cu2+ in solution by CL emission. A linear increase was observed between CL intensity and Cu2+ concentration. The CDs-Cl,P-H2O2-KMnO4 system allowed the detection of Cu2+ down to lower concentration of 0.1 mu M with a linear range of 0.2-60.0 mu M. Moreover, TA as a common polyphenolic compound, could selectively decrease the CL signal of the CDs-Cl,P-H2O2-KMnO4-Cu2+ system due to its complexation with Cu2+. On this basis, the CL assay for TA was also developed. The detection limit was 0.14 mu M and the linear range was from 5.0 mu M to 100.0 mu M. The proposed method was successfully applied to the determination of Cu2+ and TA in water, rice dumplings leaves, sodium copper chlorophyllin and wine samples with satisfactory results.
      原文链接:
    • NSTL
    • Elsevier

    A new technology for rapid determination of isomers of hydroxybenzoic acid by terahertz spectroscopy

    Tu, ShanWang, ZhigangZhang, WentaoShe, Yulai...
    12页
    查看更多>>摘要：This study investigated the feasibility of using terahertz (THz) technology for the rapid identification of isomers. The time-domain spectra of 2-hydroxybenzoic acid (2-HA), 3-hydroxybenzoic acid (3-HA), and 4-hydroxybenzoic acid (4-HA) were measured by a THz time-domain spectroscopy system (THz-TDS) in the range of 0.3-1.8 THz. Aiming at the isomer classification problem, a THz spectral data classification model based on a variational mode decomposition-particle swarm optimization-support vector machine (VMD-PSO-SVM) method was proposed. Empirical mode decomposition (EMD) and variational mode decomposition (VMD) were used to extract the first eight intrinsic mode functions (IMFs) of the time domain signal. Principal component analysis (PCA) was used to extract the first 80 principal components of each modal component as the classification feature vector. The particle swarm optimization (PSO) and support vector machine (SVM) algorithms were used to construct 2-, 3-, and 4-HA classification models. We found that the prediction accuracy of the VMD-PSO-SVM model was significantly higher than that of EMD-PSO-SVM model regardless of the modal components. For both EMD and VMD, with the increase in the IMF number, the corresponding classification recognition accuracy tended to decrease. The results showed that the rapid identification model of hydroxybenzoic acid isomers based on THz spectroscopy and SVM was effective and feasible, providing an accurate and rapid method for the chemical synthesis and quality monitoring of biomedicine. (c) 2022 Published by Elsevier B.V.
      原文链接:
    • NSTL
    • Elsevier