查看更多>>摘要：Bisulfite and hydrazine are harmful to the environment safety and human health. Therefore, it is of great value to develop a smart fluorescent probe with high selectivity for detection of bisulfite and hydrazine. In our report, a dual-response fluorescent probe EDBI with high selectivity, rapid response, and low detection limit for discriminative determination HSO3- and N2H4 was exploited. The probe EDBI is capable of distinctive sensing HSO3- and N2H4 based on nucleophilic addition reactions by taking advantage of ratiometric fluorescence and fluorescence "on-off" mode, respectively. The dual-responses behaviors of probe EDBI toward HSO3- and N2H4 were attribute to different reaction sites, which it has been confirmed by HRMS. More importantly, cytotoxicity experiment authenticated that probe possesses low toxicity and good penetration. The probe EDBI with excellent performance, it was successfully employed to distinguishable sense HSO3- and N2H4 in living cells by diverse channel patterns. Therefore, this simple dual-response fluorescence probe is expected to be used for real-time monitoring bisulfite and hydrazine in biological samples. (C) 2021 Published by Elsevier B.V.
查看更多>>摘要：Detection of the mineral constituents in a batch of 310 samples of human urinary calculi (kidney stones235 and bladder stones-75) combined with a semi-quantitative analysis has been presented on the basis of Fourier Transform based IR and Raman spectral measurements. Some of the observed characteristic IR and Raman bands have been proposed as 'Marker Bands' for the most reliable identification of the constituents. A detailed vibrational spectral analysis combined with a DFT level calculation for the functional groups in Calcium Oxalate Monohydrate (COM), Magnesium Ammonium Phosphate Hexahydrate (MAPH), Calcium Hydrogen Phosphate Dihydrate (CHPD), Penta-Calcium Hydroxy-Triphosphate (PCHT) and Uric Acid (UA) has been proposed. It has been shown that the identified mineral constituents as major or minor components can be deduced from the application of Lambert-Beer law of radiation absorption and results are in agreement with quantitative Spectral Data base. This simple method has the potential to be integrated into the management of Urolithiasis, a process of forming renal calculi in the kidney, bladder and/or urethra. Employment of powder XRD, TGA, SEM, TXRF and IR Imaging techniques has provided additional support for the proposed foolproof identification of the mineral constituents. Among the mineral constituents, Calcium Oxalate Monohydrate, Calcium Oxalate Dihydrate or their mixture account for 85% of the total number of samples; the remaining 15% and 5% samples contain Phosphate and Uric acid stones respectively. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this paper, polyvinylpyrrolidone-templated copper nanoclusters (PVP-CuNCs) were synthesised using a hydrothermal method. Through the electrostatic interaction between PVP-CuNCs and rhodamine 6G, a dual-emission ratiometric fluorescent probe was constructed, and two well-separated emission peaks appeared at 420 nm and 570 nm. The selective detection of rutin and picric acid was achieved by fitting the relationship between the ratiometric fluorescence intensity (F-420/F-570) and the concentration of the target detection substance. The limits of detection of rutin and picric acid were 0.84 mu M and 0.27 mu M, respectively. The synthesised material has high stability and successfully allows the determination of rutin content in drugs and picric acid content in water samples with satisfactory recoveries. (C) 2021 Elsevier B.V. All rights reserved.
Grace, Esther Elizabeth C.Mary, Briget M.Vaidyanathan, SeetharamanSrisudha, S....
17页
查看更多>>摘要：Two green microalgae species Monoraphidium contortum (M. contortum) and Chlamydomonas sp. that were identified to accumulate lipids were subjected to four different nutrient treatments (NP1-NP4), ranging in nitrate (0.05-5 mM N) and phosphate (2.8-264 mu M P) concentrations, at a fixed N:P ratio of similar to 18. The effect of nutrient variation on lipid productivity in the species was investigated using second derivative (SD) FTIR and Raman spectroscopy of algal biomass. SD spectral analysis revealed high production of lipid in the form of hydrocarbons (CH) (3000-2800 cm(-1)), triacylglycerides (TAGs)(similar to 1740 cm(-1)), saturated (SFA)(similar to 1440 cm(-1)), and unsaturated fatty acids (UFA)(similar to 3010 cm(-1)) for the nutrient deplete condition (NP1) in both species. Changes in signals attributed to lipids in proportion to other biochemical components were consistent with physiological changes expected from nutrient depletion. Relative signal intensities for lipids showed a significant increase in NP1, in particular, CH, TAGs in relation to protein signals (in SD-FTIR), and SFA, UFA in relation to carotenoid signals (in SD-Raman). PCA performed on the negative spectral values of the SD-FTIR and SD-Raman data for the four NP treatments enabled discrimination not only between the species but also between the NP treatments and the timing of harvest. M. contortum was found to contain a relatively higher proportion of CH, TAGs, SFA, and UFA compared to Chlamydomonas sp. Peak areas from the negative SD spectra, informed by PCA analysis, enabled capturing quantifiable changes in a manner that is consistent with known microalgal physiology. SD-FTIR and SD-Raman spectroscopy have been shown to possess superior potential to capture relevant microalgal physiological changes. (C) 2021 Elsevier B.V. All rights reserved.
Silveira, Amanda LemesSanches Barbeira, Paulo Jorge
7页
查看更多>>摘要：Although cachaca and rum are distilled beverages obtained from the same raw material, they present differences in their chemical compositions. In this study, synchronous fluorescence spectroscopy was used combined with supervised classification models based on the partial least squares discriminant analysis to develop a rapid and low-cost model for discriminating between 50 cachaca and 40 rum samples. Partial least squares discriminant analysis models were constructed using synchronous fluorescence spectra recorded at wavelength differences of 10-100 nm. Initially, spectra were preprocessed by the first derivative with the Savitzky-Golay smoothing, and filter width and polynomial order were selected through face-centered central composite designs. For the construction and validation models, the spectra data were split into two datasets: the training and the test sets containing 60 (C, n = 33; R, n = 27) and 30 (C, n = 17; R, n = 13) samples, respectively. The best discrimination was achieved using fluorescence spectra recorded at wavelength difference 10 nm, allowing the discrimination of cachaca and rum with a classification efficiency of 98%. These results indicate that synchronous fluorescence spectroscopy offers a promising approach for the authentication of cachacas and rums. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Keteling capsules (KCs), as a kind of Traditional Chinese Medicine (TCM), have been widely used in curing cough and relieving asthma. However, the complicated compositions make it challenging to evaluate their quality consistency by common methods. Herein, we explored comprehensive and efficient strategies by combining the multiple techniques to monitor and assess the characteristics of KCs. We employed the fingerprints and corresponding quantum fingerprints by fourier transform infrared spectroscopy (FT-IR), ultraviolet (UV), and differential scanning calorimetry (DSC). The antioxidant activity profiles were also studied combined with the result of three-dimensional quantum fingerprints and showed a good correlation with the internal structure and physical-chemical state. Furthermore, the 17 samples were separated and identified simultaneously by HPLC quantitative fingerprint, of which four active ingredients (chlorogenic acid, p-coumaric acid, vitexin and isovitexin) were quantitatively determined. The 17 samples were successfully classified into different grades by the systematically quantified fingerprint method (SQFM) and the quality of the samples was integrated according to the mean algorithm. The mean algorithm fusion of different evaluation techniques was compared to reveal the relationship between them, which indicated the effective improvement in accuracy and integrality. The combination of multiple analytical techniques developed in this study would effectively improve the existing single analytical methods and provide new strategy for drug quality consistency control. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：The fluorescent organic nanoparticles (FONs)-based sensor has been attracting great attention in recent years. There are still big challenges in the preparation and application of FONs-based sensor. In this study, a FONs-based sensor was designed and developed through facile hydrothermal process using 3-perylenecarboxaldehyde (PlCA) as the fluorophore and L-methionine (Met) as the recognition site for mercury ions. According to the experimental results, the fluorescence intensity of the as-prepared PlCA-M would decrease when adding Hg2+ and the mechanism was extrapolated to be photoinduced electron transfer inducing by specific coordination interaction. The acquired PlCA-M-based sensor was used to monitor Hg2+ in several real samples (environmental water, tea, and apple) with the limit of detection being 60 nM. Remarkably, a visual detection device based on FONs, SDS-PAAG (sodium dodecyl sulfate polyacrylamide gel) @PlCA-M was firstly constructed and successfully used to Hg2+ semiquantitation by naked eyes. In addition, the acquired FONs was applied into imaging tool for security information detection and identified as solid-state luminescent material for the first time. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Hexagonal boron nitrides (hBNs) have a very high luminescence efficiency and are promising materials for deep-UV emitters. Although intense deep-UV emissions have been recorded in various forms of hBN excited by photons or energetic electrons, information on the electronic structure of the conduction band has been derived mainly from theoretical works. Therefore, there is a lack of high-resolution absorption data in the far-UV region. In this study, the far-UV absorption spectra of chemical-vapor-deposition-grown mono- and multilayer hBNs were recorded at 10 and 298 K. In addition to the previously reported band at 6.10 eV, two absorption bands at 6.82 and 8.86 eV were observed for the first time in thin-film hBN. Furthermore, excitation of the hBN thin film samples with 6.89-eV photons revealed intense emission peaks at 6.10 (mono) and 5.98 (multi) eV with a bandwidth of similar to 0.7 eV. Comparing the absorption and photoluminescence data, we believe that both direct and indirect transitions occur in the radiative processes. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The excessive content of additives in food is a radical problem that affects human health. However, traditional chemical methods are limited by a long cycle, low accuracy, and strong destructiveness, so a fast and accurate alternative is urgently needed. This paper proposes a prediction model introducing near-infrared spectroscopy and deep learning to perform fast and accurate non-destructive detection of artificial bright blue pigment in cream. The model results show that R-2 is 0.9638, RMSEP is 0.0157, and RPD is 4.4022. In the preprocessing part, this paper compares the traditional preprocessing methods (SNV, MSC, SG) horizontally and innovatively proposes the use of autoencoders to mitigate the dimensionality of data, which has immensely improved the follow-up prediction effect. In addition, it tries to perform regression prediction on spectral data and establish a fully connected convolutional neural network model through deep learning, whose result indicators prove better than those of traditional methods such as PLSR and MLR. When constructing the deep learning model, this paper applies knowledge evolution to compress the model to achieve a lower calculation cost and higher accuracy. Compared with the traditional methods, the model proposed in this paper has greater accuracy and higher speed with samples undamaged, which is worth popularizing. (C) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this work, a fluorescent probe, RhodCl-Hz, with pH-applicative capability and long measuring range, was developed to serve the topic on the enrichment process of hydrazine. It was practical due to the clear acid-base boundary and the sectioned linear ranges. With the excitation wavelength of 515 nm and the emission peak at 565 nm, the detecting system was steady. It exhibited a clear cut-off point at pH 7.0 and steady fluorescence signals within the range of 7.0-10.0. As a whole, the linear range of 10.0-500 mu M (1.0-50.0 equivalent) was long. The Limit of Detection value was calculated as 0.64 mu M. With high selectivity, RhodCl-Hz was applied to suit water samples and biological imaging in both Arabidopsis Thaliana root tips and living MCF-7 cells. The information here might be helpful for revealing the enrichment process of hydrazine. (C) 2021 Elsevier B.V. All rights reserved.
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