查看更多>>摘要：Citrate salts are widely used as food additives and medicines for health and treatment. Accurate and fast detection of citrate salts is most important in food industry and medicine health. In this work, terahertz (THz) time-domain spectroscopy was used to detect and analyze different citrate salts and differentiate their crystalline hydrates. Effects of the crystalline state, the crystallization water and the metal cation on the THz spectra of citrate salts were investigated. Results indicate the crystalline states of the citrate salt samples strongly influence their THz featuring absorption peaks and citrate salts with crystallization water have larger absorption coefficients at the same frequency and higher possibility of existing featur-ing absorption peaks in comparison with citrate salts without crystallization water. Size of the metal cation also influences the THz absorption peak of the citrate salt and a small cation radius results in a large absorption peak frequency. This work illustrates the terahertz spectroscopy can be well used as a new technique to detect the citrate salts and differentiate their crystalline hydrates.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Tetracyclines (TCs), a type of antibiotics, are widely used in human therapy and animal husbandry. Public concerns about tetracyclines residues have been raised due to their negative impact on the environment and food, causing bacterias drug resistance and human health concerns. In this work, a luminescent europium MOF (EuUCBA) is constructed via post-synthetic attachment of Eu3+ into a UiO-66 type MOF. The luminescent of EuUCBA exhibits high stability in aqueous media in the pH range of 4-11. Among 36 common veterinary drugs, the synthesized probe is highly selective and sensitive to six tetracyclines with low detection limits of 0.118 mu M, 0.228 mu M, 0.102 mu M, 0.138 mu M, 0.206 mu M, and 0.078 mu M for oxytetracycline (OTC), chlortetracycline (CTC), methylenetetracycline (MTC), minocycline (MOC), tetracycline (TC), and doxycycline (DOXY), respectively. Furthermore, the probe shows good anti-interference ability and fast response. Finally, EuUCBA was successfully to detect DOXY in swine wastewater and pig kidney with good recoveries. This work provides an excellent fluorescent sensor for highly selective and rapid detection of TCs residues in wastewater and complex biological samples. (c) 2022 Elsevier B.V. All rights reserved.
Michalowska, AleksandraKudelski, AndrzejKrajczewski, Jan
12页
查看更多>>摘要：Nanostructures made of magnetic cores (Fe3O4) with many smaller plasmonic (Au) nanostructures attached were covered with a very thin layer of silica. The first example of the application of this type of material for surface-enhanced Raman scattering (SERS) measurements is presented. (Fe3O4@Au) @SiO2 nanoparticles turned out to be very efficient substrates for SERS measurements. Moreover, due to the nanomaterial's strong magnetic properties, it can be easily manipulated using a magnetic field, and it is therefore possible to form homogeneous layers (with no significant 'coffee-ring' effect) of (Fe3O4@Au)@SiO2 nanoparticles using a very simple procedure: depositing a drop of a sol of such nanoparticles and evaporating the solvent after placing the sample in a strong magnetic field. Synthesised (Fe3O4@Au)@SiO2 nanostructures have been used for the SERS detection of penicillin G in milk. Good quality SERS spectra of penicillin G were obtained even at a concentration of penicillin G in milk of 1 nmol/l - this means that the SERS detection of penicillin G in milk is possible at a concentration lower than the maximum residue limit of penicillin G in milk established by the European Commission. . (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
查看更多>>摘要：Screening for microbial contaminants in fresh produce is a lengthy process relative to their short shelf life. The aim of this study is to develop a comprehensive assay which employs FTIR and spectral classification algorithm for detection of bacterial contamination of fresh produce.The procedure starts by soaking a sample of the fresh produce in broth for 5 h. Then, magnetic nanoparticles are added to capture bacteria which are then collected and prepared for FTIR scanning. The generated FTIR spectra are compared against an in-house database of different bacterial species (n = 6). The ability of the database to discriminate contaminated and uncontaminated samples and to identify the bacterial species was assessed. The compatibility of the FTIR procedures with subsequent DNA extraction and PCR was tested. The developed procedure was applied for assessment of bacterial contamination in fresh produce samples from the market (n = 78). Results were compared to the conventional culture methods.The generated FTIR database coupled to spectral classification was able to detect bacterial contamination with overall accuracy exceeding 90%. The sample processing did not alter the integrity of the bacterial DNA which was suitable for PCR. On application to fresh produce samples collected from the market, the developed method was able to detect bacterial contamination with 94% concordance with the culture method.In conclusion, the developed procedure can be applied for fast detection of microbial contamination in fresh produce with comparable accuracy to conventional microbiological assays and is compatible with subsequent molecular assays.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Computational studies introduce an integral approach for finding greener methods through testing solvents for reactions and extractions. Lesinurad is a novel selective uric acid reabsorption inhibitor prescribed for the treatment of chronic gout. Computational calculations were achieved to choose the best acid dye used for sensitive visible spectrophotometric determination of lesinurad. The calculations were performed using Gaussian 03 software based on density functional theory method with B3LYP/631G(d) basis set. The obtained results revealed that bromophenol blue was preferred for lesinurad than other acid dyes based on the higher calculated interaction energy. The described method was based on the reaction of lesinurad with the theoretically selected acid dye bromophenol blue to form a yellow ion-pair complex. The absorption spectra showed maximum sharp peaks at 418 nm. Different factors affecting the reaction were optimized. Beer's law was demonstrated over the concentration range of 2-12 lg/mL lesinurad. The described reaction was utilized for the spectrophotometric determination of lesinurad in pure form and in the pharmaceutical preparation. The greenness of the described method was assessed using four different tools namely, the national environmental method index, the analytical eco-scale, the green analytical procedure index and the novel analytical greenness metric. The proposed method seemed to be superior to the reported HPLC method with respect to the metrics of the greenness characters.
查看更多>>摘要：A dansyl derivative-based fluorescent probe, namely, DGly, was developed for relay detection of Cu2+ and bovine serum albumin (BSA) with high selectivity and sensitivity. The fluorescence intensity of DGly at 540 nm displayed "on-off-on " phenomenon after Cu2+ and BSA were added in sequence. Correspondingly, the solution color changed from yellow to dark and then to yellowish white under 365 nm UV light irradiation; thus, the solution could be detected by the naked eye. The association constant of DGly-Cu2+ was stronger than that of DGly-BSA and DGly-Cu2+-BSA. Hence, BSA was detected after a complex was formed between DGly and Cu2+. The relay detection of Cu2+ and BSA was not influenced by other competitive interferents, and the detection limits of Cu2+ and BSA were 1.32 and 0.26 lM, respectively. Analysis of Cu2+ in real water samples validated the detection performance of the method proposed herein; it achieved satisfactory recovery and relative standard deviation values. This work demonstrated that introducing metal ions can be an effective way to improve the sensitivity of BSA detection. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：A colorimetric and fluorescent chemosensor (CS1) for Cu2+ based on the mechanism of internal charge transfer (ICT) has been successfully designed and prepared by simple condensation of 4_(diethylamino) salicylaldehyde and oxalyl dihydrazide. Cu2+ in solution (DMSO/H2O = 7:3, v/v) by 5 mM NaAc-HAc at pH 7.0 was determined through dual channels: (1) "naked-eye " observation, a visually dramatic color change from light green to orange, which can be used for qualitative determination of Cu2+; (2) spectrofluorometry, which can quantificationally assay Cu2+. It provides a simple-to-use platform for reliable detection of Cu2+ at concentrations ranging from 5.0 x 10-7 to 1.1 x 10(-5) M with detection limit of 1.2 x 10(-7) M, which is nearly 2 x 10(2) times lower than the maximum allowable level of inorganic Cu2+ in drinking water (1.3 ppm,-20 lM) permitted by the EPA (Environmental Protection Agency), and the sensing detection of Cu2+ ions was reversible.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Diabetic cardiomyopathy (DbCM) is a serious complication of diabetes that affects about 12% of the diabetic population. Sensitive detection of diabetes-induced biochemical changes in the heart before symptoms appear can assist clinicians in developing targeted treatment plans and forensic pathologists in making accurate postmortem diagnoses. The Fourier transform infrared (FTIR) spectroscopy-based approach allows for the analysis of the sample biomolecular composition and variations. In the current study, the myocardial tissues of mouse models of type 2 diabetes mellitus (T2DM) at various ages (7, 12, and 21 weeks) were analyzed using FTIR microspectroscopy (FTIRM) in combination with machine learning algorithms. The carbonyl esters, olefinic=CH and CH2 groups of lipids, total lipids, saccharides, and beta-sheet to alpha-helix conformational transition in proteins increased significantly in diabetic mice myocardial tissues compared to healthy mice. Furthermore, partial least-squares discriminant analysis and random forest-guided partial least-squares discriminant analysis revealed the time-dependent progression of the spectral lipidomic profiles during the development of DbCM. Finally, a random forest classifier was developed for diagnosing DbCM, with 97.1% accuracy. This study demonstrates that FTIRM is a novel method for monitoring early biochemical changes in the myocardia of mice with T2DM. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Fourier transform-based algorithms were investigated to resolve UV spectral overlapping of spiramycin and metronidazole in binary mixtures. UV spectra and ratio spectra were both subjected to fast Fourier transform-based first-order differentiation and discrete Fourier transform {i.e. using trigonometric functions such as sin xi - sin (x(i) + 45(0)), cos x(i) + cos (x(i)+ 45(0))), sin 2x(i) - sin 2(x(i) + 450), cos 2x(i) + cos 2(x(i) + 45(0))), sin xi - sin (x(i) + 60(0))), cos x(i) + cos (x(i) + 60(0)))} that followed by 3 passes of 17-point triangular smooth. Such signal transforms generated linear calibration graphs for either drug in the concentration range of 6.25 - 25 mg/L with R-2 > 0.990. In comparison with the RP-HPLC reference method, the developed UV spectrophotometric methods had no significant difference in terms of accuracy and precision (p > 0.05) when quantifying spiramycin and metronidazole in their coated tablets. They are suggested as analytical quality control methods for their being environmentally friendly, technically simple, quick and economic. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：We developed a dual-wavelength-excitation aerosol fluorescence spectra detection device prototype. In our system, the 263 nm and 355 nm lasers are used to sequentially excite the fluorescence of aerosol stream, which is located spatially and temporally by two crossed infrared lasers; a bifurcated fiber bundle is applied to receive the fluorescence spectra of 274-463 nm and 374-565 nm. Besides, with a 32 channel photomultiplier tube as detector, a self-developed combined spectrometer with Czerny-Turner design is employed to detect the two band spectra in a preset timing sequence. Experiments show that the system can detect the fluorescence spectra, after dual-wavelength-excitation, of three intrinsic fluorophore samples and three bioaerosol samples. CO 2022 Published by Elsevier B.V.
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