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1.
Anal Chim Acta ; 1251: 340983, 2023 Apr 22.
Article in English | MEDLINE | ID: mdl-36925281

ABSTRACT

Dual-signal ratiometric molecularly imprinted polymer (MIP) electrochemical sensors with bimetallic active sites and high-efficiency catalytic activity were fabricated for the sensing of catechol (CC) with high selectivity and sensitivity. The amino-functionalization bimetallic organic framework materials (Fe@Ti-MOF-NH2), coupled with two-dimensional layered titanium carbide (MXene) co-modified glassy carbon electrode provides an expanded surface while amplifying the output signal through the electropolymerization immobilization of polythionine (pTHi) and MIP. The oxidation of CC and pTHi were presented as the response signal and the internal reference signal. The oxidation peak current at +0.42 V rose with increased concentration of CC, while the peak currents of pTHi at -0.20 V remained constant. Compared to the common single-signal sensing system, this one (MIP/pTHi/MXene/Fe@Ti-MOF-NH2/GCE), a novel ratiometric MIP electrochemical sensor exhibited two segments wide dynamic range of 1.0-300 µM (R2 = 0.9924) and 300-4000 µM (R2 = 0.9912), as well as an ultralow detection limit of 0.54 µM (S/N = 3). Due to the specific recognition function of MIPs and the advantages of built-in correction of pTHi, the prepared surface imprinting sensor presented an excellent performance in selectivity and reproducibility. Besides, this sensor possessed superior anti-interference ability with ions and biomolecules, excellent reproducibility, repeatability, and acceptable stability. Furthermore, the proposed sensing system exhibits high specific recognition in the determination of environmental matrices and biological fluids in real samples with satisfactory results. Therefore, this signal-enhanced ratiometric MIP electrochemical sensing strategy can accurately and selectively analyze and detect other substances.


Subject(s)
Molecular Imprinting , Molecular Imprinting/methods , Reproducibility of Results , Carbon , Catechols , Electrochemical Techniques/methods , Limit of Detection , Electrodes
2.
Article in English | MEDLINE | ID: mdl-36750421

ABSTRACT

An optical monitoring device combining a smartphone with a polychromatic ratiometric fluorescence-colorimetric paper sensor was developed to detect Hg2+ and S2- in water and seafood. This monitoring included the detection of food deterioration and was made possible by processing the sensing data with a machine learning algorithm. The polychromatic fluorescence sensor was composed of blue fluorescent carbon quantum dots (CDs) (BU-CDs) and green and red fluorescent CdZnTe quantum dots (QDs) (named GN-QDs and RD-QDs, respectively). The experimental results and density functional theory (DFT) prove that the incorporation of Zn can improve the stability and quantum yield of CdZnTe QDs. According to the dynamic and static quenching mechanisms, GN-QDs and RD-QDs were quenched by Hg2+ and sulfide, respectively, but BU-CDs were not sensitive to them. The system colors change from green to red to blue as the concentration of the two detectors rises, and the limits of detection (LOD) were 0.002 and 1.488 µM, respectively. Meanwhile, the probe was combined with the hydrogel to construct a visual sensing intelligent test strip, which realized the monitoring of food freshness. In addition, a smartphone device assisted by multiple machine learning methods was used to text Hg2+ and sulfide in real samples. It can be concluded that the fabulous stability, sensitivity, and practicality exhibited by this sensing mechanism give it unlimited potential for assessing the contents of toxic and hazardous substances Hg2+ and sulfide.

3.
Food Chem ; 413: 135640, 2023 Jul 01.
Article in English | MEDLINE | ID: mdl-36758385

ABSTRACT

Here, a smartphone-assisted dual-color ratiometric fluorescence smart gel label-based visual sensing platform was constructed for real-time evaluation of the freshness of agro-food based on the biogenic amines responses. Green-emission fluorescence carbon dots (CDs) coupled with blue-emission fluorescence bimetallic metal-organic framework (Fe/Zr-MOF) obtained dual-color CDs@Fe/Zr-MOF fluorescence nanoprobe acts as the response units. With the increase of SP and HIS content, the green fluorescence of CDs was enhanced, while the blue fluorescence of Fe/Zr-MOF was quenched. Therefore, this dual-color probe achieved a clear fluorescence color response to biogenic amines. The nanoprobe possessed sensitive and color-responsive with the LODs of 0.17 µM for SP and 2.95 µM for HIS in a wide range of 0-937.5 µM, respectively. Besides, these fluorescent nanoprobes were immobilized on the hydrogel carrier, and the intelligent fluorescent hydrogel tag can be obtained after freeze-drying, which realizes the real-time qualitative monitoring of SP and HIS in pork and shrimp samples.


Subject(s)
Deep Learning , Quantum Dots , Smartphone , Limit of Detection , Seafood , Hydrogels , Fluorescent Dyes , Carbon
4.
Biosens Bioelectron ; 225: 115108, 2023 Apr 01.
Article in English | MEDLINE | ID: mdl-36709587

ABSTRACT

Aggregation of ß-amyloid (Aß) were considered as a typical pathological feature of Alzheimer's disease (AD). Extensive studies have verified that soluble Aß oligomers (AßO) were more toxic to neurons than plaques. Herein, in this work, a glucose entrapped liposome-based portable aptasensor was fabricated for recognizing and interacting with AßO by specific aptamer on liposome (G-Lip-Apt). Then, a single strand DNA, designed to be partially complementary to AßO aptamer, was modified on amino-functionalized Fe3O4@SiO2 to obtain a magnetic nanocomposite (Fe3O4@SiO2/NH2-DNA). In the presence of AßO, the specific recognition between AßO and its aptamer on G-Lip-Apt made AßO bounded with G-Lip-Apt. With subsequent introduction of Fe3O4@SiO2/NH2-DNA, the unreacted G-Lip-Apt was further linked with Fe3O4@SiO2/NH2-DNA by double stranded complementary pairing interaction. Along with the addition of TritonX-100 into the formed G-Lip-Apt/Fe3O4@SiO2/NH2-DNA complex, the encapsulated glucose was released from liposome and then measured by a personal glucose meter (PGM). Good linear correlation was acquired over concentration of 5.0-1000 nM and the limit of detection (LOD) was calculated to be 2.27 nM for AßO. The developed portable electrochemical strategy integrated magnetic separation, competitive reaction and point of care test (POCT) to achieve high sensitivity, selectivity and accuracy, therefore enabled it successfully applied to the analysis of AßO in the hippocampus and cortex of APP/PS1 transgenic AD mice.


Subject(s)
Alzheimer Disease , Aptamers, Nucleotide , Biosensing Techniques , Mice , Animals , Liposomes , Silicon Dioxide , Alzheimer Disease/diagnosis , Amyloid beta-Peptides/analysis , Mice, Transgenic , DNA
5.
Biosens Bioelectron ; 222: 114996, 2023 Feb 15.
Article in English | MEDLINE | ID: mdl-36521203

ABSTRACT

Here, a novel and portable machine learning-assisted smartphone-based visual molecularly imprinted ratiometric electrochemiluminescence (MIRECL) sensing platform was constructed for highly selective sensitive detection of 2,4-Dichlorophenoxyacetic acid (2,4-D) for the first time. Te doped CdS-coated Mn3O4 (Te-CdS@Mn3O4) with catalase-like activity served as cathode-emitter, while luminol as anode luminophore accompanied H2O2 as co-reactant, and Te-CdS@Mn3O4 decorated molecularly imprinted polymers (MIPs) as recognition unit, respectively. Molecular models were constructed and MIP band and binding energies were calculated to elucidate the luminescence mechanism and select the best functional monomers. The peroxidase activity and the large specific surface area of Mn3O4 and the electrochemical effect can significantly improve the ECL intensity and analytical sensitivity of Te-CdS@Mn3O4. 2,4-D-MIPs were fabricated by in-situ electrochemical polymerization, and the rebinding of 2,4-D inhibits the binding of H2O2 to the anode emitter, and with the increase of the cathode impedance, the ECL response of Te-CdS@Mn3O4 decreases significantly. However, the blocked reaction of luminol on the anode surface also reduces the ECL response. Thus, a double-reduced MIRECL sensing system was designed and exhibited remarkable performance in sensitivity and selectivity due to the specific recognition of MIPs and the inherent ratio correction effect. Wider linear range in the range of 1 nM-100 µM with a detection limit of 0.63 nM for 2,4-D detection. Interestingly, a portable and visual smartphone-based MIRECL analysis system was established based on the capture of luminescence images by smartphones, classification and recognition by convolutional neural networks, and color analysis by self-developed software. Therefore, the developed MIRECL sensor is suitable for integration with portable devices for intelligent, convenient, and fast detection of 2,4-D in real samples.


Subject(s)
Biosensing Techniques , Molecular Imprinting , Molecular Imprinting/methods , Smartphone , Luminol/chemistry , Hydrogen Peroxide , Luminescent Measurements/methods , Biosensing Techniques/methods , Limit of Detection , Molecularly Imprinted Polymers , 2,4-Dichlorophenoxyacetic Acid , Electrochemical Techniques/methods
6.
Anal Chem ; 93(41): 13823-13834, 2021 10 19.
Article in English | MEDLINE | ID: mdl-34609144

ABSTRACT

In view of the close association of ß-amyloid oligomers (AßO) with the clinical development of Alzheimer's disease (AD) symptoms, it is urgent to design a promising sensing and therapeutic strategy that can target AßO for preventing or delaying the onset of AD. Herein, a core-shell nanocomposite CeONP-Res-PCM@ZIF-8/polydopamine (PDA) was synthesized through an in situ encapsulated strategy, in which resveratrol (Res), ceria nanoparticles (CeONPs), and PCM (tetradecanol) were embedded into the ZIF-8/PDA matrix via a water-based mild approach. Using the AßO aptamer, the ability of CeONP-Res-PCM@ZIF-8/PDA/Apt as the fluorescent sensing platform for AßO detection and intracellular imaging was demonstrated. The nanocomposite was high in Res loading (27.5%) and could be activated to release the encapsulated Res upon illumination with NIR through PCM regulation. Moreover, due to the synergetic interactions of PDA, CeONPs, and Res in one system, CeONP-Res-PCM@ZIF-8/PDA/Apt nanocomposites exhibited multifunctional effects on inhibiting Aß aggregation, degrading Aß fibrils, and alleviating Aß-induced oxidative stress and neural apoptosis. These therapeutic effects could be enhanced under NIR irradiation by virtue of the excellent photothermal property of PDA. As far as we know, there is no report of using ZIF-8-based materials for simultaneous sensing and therapeutic applications. This work boosted the development of multifunctional nanoagents for biomedical research studies.


Subject(s)
Hyperthermia, Induced , Metal-Organic Frameworks , Nanoparticles , Doxorubicin , Phototherapy
7.
Adv Mater ; 33(24): e2007900, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33960020

ABSTRACT

Self-limited nanoassemblies, such as supraparticles (SPs), can be made from virtually any nanoscale components, but SPs from nanocarbons including graphene quantum dots (GQDs), are hardly known because of the weak van der Waals attraction between them. Here it is shown that highly uniform SPs from GQDs can be successfully assembled when the components are bridged by Tb3+ ions supplementing van der Waals interactions. Furthermore, they can be coassembled with superoxide dismutase, which also has weak attraction to GQDs. Tight structural integration of multilevel components into SPs enables efficient transfer of excitonic energy from GQDs and protein to Tb3+ . This mechanism is activated when Cu2+ is reduced to Cu1+ by nitric oxide (NO)-an important biomarker for viral pulmonary infections and Alzheimer's disease. Due to multipronged fluorescence enhancement, the limit of NO detection improves 200 times reaching 10 × 10-12 m. Furthermore, the uniform size of SPs enables digitization of the NO detection using the single particle detection format resulting in confident registration of as few as 600 molecules mL-1 . The practicality of the SP-based assay is demonstrated by the successful monitoring of NO in human breath. The biocompatible SPs combining proteins, carbonaceous nanostructures, and ionic components provide a general path for engineering uniquely sensitive assays for noninvasive tracking of infections and other diseases.


Subject(s)
Graphite , Nitric Oxide , Spectrometry, Fluorescence
8.
Anal Chim Acta ; 1151: 338250, 2021 Mar 22.
Article in English | MEDLINE | ID: mdl-33608077

ABSTRACT

Clinical vancomycin (Van) treatment is administered over a prolonged period to achieve a sustained therapeutic effect. Accurate, rapid, and continuous Van detection is an unmet medical monitoring need that can provide data-based guidance for doctors to adjust the dosage and treatment plan in real-world settings. In this study, we created a Van-specific, fluorescent biosensor that was combined with a microdialysis sampling technique to develop a rapid, simple, accurate, and sensitive detection method, which was validated for Van in vivo. A Van-specific probe was created by separately conjugating each of the two peptide chains of a dimeric derivative of the Van binding peptide L-Lys-D-Ala-D-Ala to a fluorescent dansyl chloride group. Subject-specific pharmacokinetics of Van was recorded in normal rabbits and rabbits with adenine-induced chronic renal failure (CRF), which indicated the feasibility of therapeutic drug monitoring in vivo. The area under the concentration-time curve (AUC0-last) was 10,715 min µg mL-1 (95% CI = 8,892 to 12,538) in the normal rabbits, and 14,822 and 19,025 min µg mL-1 in two selected CRF rabbits. Furthermore, using pharmacokinetic dosing of Van in a rabbit study, we designed the dosage and drug administration interval to achieve a sustained therapeutic effect. The normal rabbits received three Van doses, 20, 5, and 5 mg kg-1, administered at 0, 500, and 900 min, respectively. The CRF rabbits received two Van doses, 20 and 5 mg kg-1, administered at 0 and 600 min, respectively. Thus, we established an effective method for the continuous monitoring of Van. This method facilitates the detection of Van in clinical treatment and provides the scientific basis for an effective approach to monitor blood drug levels during the clinical treatment of various diseases.


Subject(s)
Biosensing Techniques , Vancomycin , Animals , Anti-Bacterial Agents , Drug Monitoring , Microdialysis , Peptides , Rabbits
9.
J Mater Chem B ; 9(1): 170-175, 2021 01 07.
Article in English | MEDLINE | ID: mdl-33230516

ABSTRACT

The development of non-invasive and sensitive optical probes for in vivo bioimaging of cancer-related enzymes is desirable for early diagnosis and effective cancer therapy. ß-galactosidase (ß-gal) is regarded as a key ovarian cancer biomarker, owing to its overexpression in primary ovarian cancer. Herein, we designed a sensitive near-infrared (NIR) probe (DCMCA-ßgal) for the detection and real-time imaging of ß-gal activity in ovarian tumors, thereby achieving the visualization of ovarian tumors by ß-gal activity detection. DCMCA-ß-gal could be triggered by ß-gal, resulting in the release of a NIR chromophore, DCM-NH2; the linear range of fluorescent response to ß-gal concentration was 0-1.2 U with a low detection limit of 1.26 × 10-3 U mL-1. We used DCMCA-ß-gal to detect and visualize ß-gal activity in SKOV3 human ovarian cancer cells, as well as for real-time imaging of ß-gal activity in ovarian cancer mouse models. DCMCA-ß-gal possessed high sensitivity, "turn-on" NIR emission, a large spectral shift, and high photostability in a dynamic living system and thus could serve as a highly sensitive sensor for real-time tracking of ß-gal activity in vivo and ovarian tumor imaging.


Subject(s)
Fluorescent Dyes/metabolism , Optical Imaging/methods , Ovarian Neoplasms/diagnostic imaging , Ovarian Neoplasms/metabolism , beta-Galactosidase/metabolism , Animals , Cell Line, Tumor , Enzyme Activation/physiology , Female , Fluorescent Dyes/analysis , HEK293 Cells , Humans , Mice , Mice, Nude , Spectroscopy, Near-Infrared/methods , beta-Galactosidase/analysis
10.
Analyst ; 145(19): 6369-6377, 2020 Sep 28.
Article in English | MEDLINE | ID: mdl-32729592

ABSTRACT

A novel and simple "off-to-on" fluorescent sensing platform for ß-amyloid oligomers (Aßo) was developed based on dye (FAM)-labeled single-strand DNA (FAM-ssDNA)-conjugated molybdenum disulfide nanosheets (MoS2 NSs). Due to strong adsorption of ss-DNA to the surface of MoS2 NSs, the fluorescence of FAM was quenched remarkably, leading to a fluorescent "off" state. However, in the presence of Aßo, a hybrid structure between Aßo and FAM-ssDNA resulted in the dissociation of FAM-ssDNA from MoS2 NSs and an obvious fluorescence recovery transformed the fluorescence to an "on" state. The developed fluorescence sensing assay showed a good linear relationship toward Aßo ranging from 0.01 to 20 µM (R2 = 0.994) with a satisfactory detection limit of 3.1 nM. Practical samples of hippocampus and cortex tissues from APP/PS1 double transgenic AD mice were applied to demonstrate feasibility of the assay. Moreover, we found that similar to MoS2 nanoparticles, MoS2 NSs possessed therapeutic effects on Alzheimer's disease (AD) by inhibiting Aß aggregations and degrading the previously formed Aß fibrils. Collectively, the high sensitivity, specificity, and good biocompatibility along with an efficient anti-aggregation ability, the presented fluorescent strategy with MoS2 NSs demonstrated their promising potential for future AD-related research.


Subject(s)
Amyloid beta-Peptides , Molybdenum , Animals , Disulfides , Fluorescence , Mice
11.
Biosci Rep ; 39(6)2019 06 28.
Article in English | MEDLINE | ID: mdl-31142631

ABSTRACT

Allicin can be used as fumigant to protect food and cultural relics from fungal contamination because of its strong antifungal activity and the characteristics of high volatility and no residues. However, the obvious disadvantages such as high minimal inhibitory concentration and instability prevent it from wide application. In this study, a stable derivative of allicin, S-ethyl ethanethiosulfinate (ALE), was synthesized. We further explored its antifungal activity and apoptosis-inducing effect, as well as the underlying mechanism. ALE had an excellent capability of inhibiting spore germination and mycelial growth of Penicillium chrysogenum observed by inverted microscope and scanning electron microscopy. XTT colorimetric assay indicated ALE could reduce the cell viability obviously and IC50 was 0.92 µg/ml, only 1/42 of allicin (38.68 µg/ml). DHR 123 ROS Assay Kit, flow cytometry assay and confocal immunofluorescence revealed intercellular ROS generation and metacaspase-dependent apoptosis triggered by ALE, while antioxidant tocopherol could reverse ALE-induced cytotoxicity effect and metacaspase activation. These results indicate that ALE induces metacaspase-dependent apoptosis through ROS generation, thus possesses an effective antifungal activity. This new derivative of allicin might be developed as a high efficient alternative to the conventional fungicides for food storage and cultural relic protection.


Subject(s)
Apoptosis/drug effects , Oxidative Stress/drug effects , Penicillium chrysogenum/metabolism , Sulfinic Acids/pharmacology , Disulfides
12.
Analyst ; 144(6): 2166-2172, 2019 Mar 21.
Article in English | MEDLINE | ID: mdl-30762055

ABSTRACT

In this study, a functionalized ionic liquid (IL), 3-methyl-1-(ethoxycarbonylmethyl) imidazolium bis(trifluoromethylsulfonyl)-imide ([MimCH2COOCH3][NTf2]), was rationally designed and explored as an extraction solvent in dispersive liquid-liquid microextraction (DLLME) combined with ultra-high performance liquid chromatography (UHPLC) for the sensitive determination of organophosphorus pesticides (OPs). As π-π stacking interaction between the parent imidazolium cation core and the OPs is one of the most important factors, the proposed IL exhibited a high extraction efficiency. Moreover, during the DLLME process, a cloudy solution containing fine drops of [MimCH2COOCH3][NTf2] allowed for a larger contact area between the OPs and the IL, which accelerated the mass transfer, and therefore the enrichment could be realized in a rapid fashion. Under the optimal extraction conditions, the developed method was successfully applied in the analysis of OPs in environmental water samples with a high enrichment factor (more than 400), good recovery and reproducibility.

13.
Environ Sci Pollut Res Int ; 25(35): 35109-35129, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30328039

ABSTRACT

Storing and exhibiting cultural heritages are the basic social functions of museum. Since it is impossible to store or display objects without using containers, cases, or holders, the equipment quality is of great importance. Evaluating the suitability of the equipment should not only learn the mechanical behavior but also focus on the materials because some of them (such as woods) may do harm to the objects due to contaminants released. A convenient test by the deposited metal film method has been proposed previously in order to evaluate more potential museum materials in limited time. The conformance between this method and the Oddy test, the classic method for evaluating and selecting museum materials, is mainly studied in this work. The two testing systems were compared from several aspects such as sample appearance, corrosion product, surface morphology, and metallic content by naked eye and modern characterization measures like X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The corrosion mechanisms were deduced according to the corrosion products, including Cu → Cu2O → CuO and Cu → Cu2O → Cu(OH)2·H2O → Cu(HCOO)(OH). The suitability of potential materials for the conservation of metal objects was defined according to the metallic contents of coupons (calculated by atomic ratio) which were classified by the Oddy test. The critical values distinguishing permanently usable from temporarily usable are approximately determined as 70% for copper and 75% for silver, and those distinguishing temporarily usable from unusable are approximately determined as 55% for copper and 60% for silver. The corresponding metal films were classified based on the metallic content standard derived, and then typical appearances of the films assigned to different suitability levels were suggested. Special phenomena, such as the failure in detecting some corrosion products, is attributed to low yield and uneven distribution of ultrafine corrosion products on the films, the covering effect caused by other corrosion products on the copper coupons, and the weakening effect resulted from intensive metal peaks, while some unexpected corrosion conditions on the coupons and the films, are related to the characteristics of general corrosion and pitting corrosion. The results indicate the potential application of the deposited metal film method, giving an optional choice to evaluate and select museum materials with less time. The evaluation methods were preliminarily established from three aspects, such as artificial judgment, metallic content analysis, and corrosion product identification. The artificial judgment is generally applicable, and the other two are useful for verifying the result if possible. More actual cases and further calibration work are essential for further development of the deposited metal film method.


Subject(s)
Copper/chemistry , Models, Chemical , Museums , Copper/analysis , Corrosion , Microscopy, Electron, Scanning , Silver/analysis , Spectrometry, X-Ray Emission , X-Ray Diffraction
14.
Sci Rep ; 6: 38417, 2016 12 02.
Article in English | MEDLINE | ID: mdl-27910926

ABSTRACT

In 2015, more than 30% of erasers were found to contain a PAE content that exceeded the 0.1% limit established by the Quality and Technology Supervision Bureau of Jiangsu Province in China. Thus, strengthening the supervision and regulation of the PAE content in foods and supplies, in particular, remains necessary. Graphene oxide (GO) and its composites have drawn great interests as promising adsorbents for polar and nonpolar compounds. However, GO-based adsorbents are typically restricted by the difficult separation after treatment because of the high pressure in filtration and low density in centrifugation. Herein, a series of novel ionic liquids modified graphene oxide composites (GO-ILs) were prepared as adsorbents for phthalates (PAEs) in eraser samples, which overcame the conventional drawbacks. These novel composites have a combination of the high surface area of graphene oxide and the tunability of the ionic liquids. It is expected that the GO-ILs composites can be used as efficient adsorbents for PAEs from aqueous solution. This work also demonstrated a new technique for GO-based materials applied in sample preparation.

15.
J Chromatogr A ; 1409: 125-31, 2015 Aug 28.
Article in English | MEDLINE | ID: mdl-26206631

ABSTRACT

Concentration of blood catecholamines (CAs) is linked to a host of cardiovascular diseases, including hypertension and stenocardia. The matrix interferences and low concentration require tedious sample pretreatment methods before quantitative analysis by the gold standard method of high-performance liquid chromatography-electrochemical detector (HPLC-ECD). Solid phase extraction (SPE) has been widely used as the pretreatment technique. Here, a facile polymeric ionic liquid (PIL)-diphenylboric acid (DPBA)-packed capillary column was prepared to selectively extract dopamine (DA), noradrenaline (NE) and epinephrine (E) prior to their quantitative analysis by a fast separation in HPLC-ECD method, while microdialysis sampling method was applied to get the analysis sample. Parameters that influenced desorption efficiency, such as pH, salt concentration, acetonitrile content and wash time, were examined and optimized. The proposed method, combining microdialysis sampling technique, SPE and HPLC-ECD system, was successfully applied to detect CAs in rat blood microdialysate with high sensitivity and selectivity in small sample volumes (5-40µl) and a short analysis time (8min), yielding good reproducibility (RSD 6.5-7.7%) and spiked recovery (91-104.4%).


Subject(s)
Boron Compounds/chemistry , Catecholamines/blood , Imidazoles/chemistry , Polystyrenes/chemistry , Animals , Chromatography, High Pressure Liquid/methods , Dopamine/blood , Electrochemical Techniques , Epinephrine/blood , Ionic Liquids , Microdialysis , Norepinephrine/blood , Polymers , Rats , Reproducibility of Results , Solid Phase Extraction/methods
16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(1): 60-4, 2015 Jan.
Article in Chinese | MEDLINE | ID: mdl-25993821

ABSTRACT

Cultural fibrous material includes both important categories, i. e. textile and paper, consisting of precious cultural materials in museum, such as costume, painting, and manuscript. In recent years more and more connoisseur and conservator's concerns are, through nondestructive method, the authenticity and the ageing identification of these cultural relics especially made from fragile materials. In this research, we used attenuated total reflection infrared spectroscopy to identify five traditional textile fibers, alongside cotton, linen, wool, mulberry silk and tussah silk, and another five paper fibers alongside straw, wheat straw, long qisong, Chinese alpine rush and mulberry bar, which are commonly used for making Chinese traditional xuan paper. The research result showed that the animal fiber (wool, mulberry silk and tussah silk) and plant fiber (cotton and linen) were easier to be distinguished by comparing the peaks at 3 280 cm-1 belonging to NH stretching vibration and a serious peaks related to amide I to amide III. In the spectrum of wool, the peak at 1 076 cm-1 was assigned to the S-O stretching vibration absorption of cystine in wool structure and can be used to tell wool from silk. The spectrum of mulberry silk and tussah silk seems somewhat difficult to be identified, as well as the spectrum of cotton and linen. Five rural paper fibers all have obvious characteristic peaks at 3 330, 2 900 cm-1 which are related to OH and CH stretching vibration. In the fingerprint wavenumber range of 1 600 - 800 cm, the similar peaks also appeared at 1 370, 1 320 cm-1 and 1 162, 1 050 cm-1, both group peaks respectively are related to CH and CO vibration in the structure of cellulose and hemicellulose in paper fibers. Although there is more similarity of the infrared spectroscopy of these 5 paper fibers, some tiny difference in absorbance also can be found at 3 300 cm-1 and in the fingerprint range at 1 332, 1 203, and 1 050 cm-1 which are related to C-O-C vibration in cellulose. Moreover, in order to explore direct and simple method to identify different materials with similar spectrum,. the principal component analysis (PCA) was applied to separate cotton and linen, mulberry silk and tussah silk, as well as five paper fibers. To eliminate and reduce the spectral scattering caused by sample uneven surface roughness, the multiplicative scatter correction (MSC) has been applied based on total spectral data. The result showed that the score plot using the first two principal components can effectively categorize both group textiles of cotton and linen, as well as mulberry silk and tussah silk, and they have similar chemical structure. For five paper fibers, the PCA was applied in different spectral range (918-550, 1 280-918, 1 700-1 280 and 3 800-2 800 cm-1), and the best result appeared in the range from 3 800 to 2 800 cm-1, in which the five paper fibers can be well categorized. This research showed that infrared spectroscopy combined with principal component analysis has great potential advantage on identifying fibrous materials with similar structure.


Subject(s)
Cellulose/analysis , Silk/analysis , Spectrophotometry, Infrared , Textiles/analysis , Wool/chemistry , Animals , Bedding and Linens , Cotton Fiber , Paper
17.
Chem Commun (Camb) ; 49(84): 9830-2, 2013 Oct 28.
Article in English | MEDLINE | ID: mdl-24030709

ABSTRACT

3-Aminobenzeneboronic acid functionalized graphene quantum dots (APBA-GQDs) were synthesized and used as a selective and sensitive sensing system for glucose. Combined with microdialysis, glucose was monitored successfully in vivo in the striatum of rat.


Subject(s)
Boronic Acids/chemistry , Fluorescent Dyes/chemistry , Glucose/analysis , Graphite/chemistry , Microdialysis , Quantum Dots , Animals , Corpus Striatum/chemistry , Rats , Spectrometry, Fluorescence
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