A plasmonic hot electron transfer-induced multicolor chromogenic system is described for label-free visual colorimetric determination of silver(I). The chromogenic system consists of plasmonic MoO
...3-x
nanosheets with oxygen vacancies and Ag(I). Under white light-emitting diode (LED) excitation, energetic hot hole-electron pairs are formed on the surface of the blue MoO
3-x
nanosheets. The resulting hot electrons are transferred to Ag(I) upon which it becomes reduced. This results in the generation of yellow silver nanoparticles. Simultaneously, the hot holes lead to the oxidation of the MoO
3-x
nanosheets to yield colorless MoO
3
nanosheets. Similarly, energetic hot hole-electron pairs can also be generated on the surface of AgNPs under white LED irradiation, which contributes to the reduction of Ag(I) and the oxidation of MoO
3-x
. Overall, a colorful transition from blue to green and finally to yellow can be observed. This multicolor chromogenic system was applied to the colorimetric determination of Ag(I) in the 33–200 μM concentration range and a 0.66 μM limit of detection, at analytical wavelengths of 430 and 760 nm. The method also is amenable to semi-quantitative visual determination of Ag(I).
Graphical abstract
Schematic representation of plasmonic hot electron transfer-induced multicolor MoO
3-x
-based chromogenic system for visual and colorimetric determination of silver(I).
There is great interest in detection of the level of 2,4,6-trinitrotoluene (TNT) explosive due to its importance in public security and environmental protection fields. The conventional chemical ...sensors do not simultaneously realize simple, rapid, sensitive, selective, and direct detection of TNT in different medium without sample pretreatment. Here we present a modified wood-based chemical sensor for visual colorimetric detection of TNT in water, air, and soil. The natural wood undergoes a delignified process, which is further functionalized by 3-aminopropyltriethoxysilane (APTES). When TNT solutions are introduced, the wood-based sensor shows a colorimetric transition from light yellow to brown for naked-eye readout because of the generation of Meisenheimer complex between APTES and TNT. The photographs are collected by smartphone camera, and the RGB components are extracted to calculate the adjusted intensity for qualitative detection of TNT. This visual colorimetric sensor for TNT solution displays a linearity in the range of 0.01–5 mM with a limit of detection of 3 μM. In addition, by taking advantage of its inherent mesostructure, the wood-based sensor can be employed for visual detection of TNT vapor as well. Furthermore, it is also able to directly detect TNT in wet soil samples based on capillary action, in which TNT carried by water transports upward along the wood microchannel, triggering the generation of Meisenheimer complex.
Graphical Abstract
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Colla corii asini
(
CCA
) made from donkey-hide has been widely used as a traditional animal-based Chinese medicine. Chondroitin sulfate (CS), dermatan sulfate (DS) and hyaluronic acid (HA) are ...structurally complex classes of glycosaminoglycans (GAGs) that have been implicated in a wide range of biological activities. However, their possible structural characteristics in CCA are not clear. In this study, GAG fractions containing CS/DS and HA were isolated from
CCA
and their disaccharide compositions were analyzed by high sensitivity liquid chromatography-ion trap/time-of-flight mass spectrometry (LC-MS-ITTOF). The result showed that CS/DS/HA disaccharides were detected in the three lower salt fractions from anion-exchange chromatography. The sulfation patterns and densities of CS/DS chains in these fractions differed greatly, while HA chains varied in their chain lengths. The quantitative analysis first revealed that the amount of GAGs in
CCA
varied significantly in total and in each fraction. This novel structural information could help clarify the possible involvement of these polysaccharides in the biological activities of
CCA
.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Despite the implementation of stringent emission reduction measures in China since 2013, ozone (O3) pollution remains a serious concern. Many O3 pollution processes are accompanied by the explosive ...growth of O3 concentration, meanwhile this explosive growth will trigger O3 pollution with a high probability. This study investigates the chemical and physical mechanisms behind the explosive growth of O3 in the summer within the Beijing-Tianjin-Hebei (BTH) region based on the atmospheric circulation clustering and WRF-CMAQ simulation. Ninety-four instances of O3 explosions from the summer of 2014–2021 were selected based on their day-to-day variation in O3 concentration, and the corresponding meteorological conditions were classified into four clusters using K-means analysis. Cluster 1 revealed that large-scale regional transmission of O3 and its precursors from the southern BTH region led to a renewed burst of O3 growth based on mild pollution. Nighttime reduction in NO2 concentration decreases titration consumption, causing a nocturnal rise in O3 concentration, detectable through observed data and progress analysis. In Cluster 2 and Cluster 3, the BTH region is located in the northeast wind area ahead of the ridge and northly wind area of post-trough situation, respectively. The vertical downward motion with the markable increase in surface solar radiation (SSR), 2-m temperature (T2M), and decrease in relative humidity (RH) contribute to photochemical O3 generation. Additionally, enhancements in boundary layer stability and reductions in dry deposition and vertical diffusion are favorable for the O3 accumulation. Cluster 4 showed the explosive growth after rainfall event, with the largest increment. The post-rain increase in SSR and T2M, coupled with decreased RH, promotes photochemical O3 formation. Moreover, progress analysis reveals the reduced cloud cover slows down O3 removal, contributing to O3 accumulation. The dominant mechanism behind the explosive growth of O3 will provide certain guidance for the prediction of O3.
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•Four types of weather drive ozone surges in Beijing-Tianjin-Hebei, intensifying pollution.•Regional transport causes a rapid rise in ozone, intensifying existing pollution.•Daytime photochemistry rises and nighttime titration weakens causing ozone surges.•Summer rains can easily trigger explosive growth in ozone, leading to ozone pollution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this work, 9-mesityl-10-methylacridinium ion (Acr+-Mes) is found to act as an effective photocatalyst mimicking the function of oxidase. Upon visible light illumination, the excited Acr+-Mes is ...able to exhibit superior enzymatic catalytic activity for small molecular substrates as well as protein biomacromolecule (cytochrome c). The experiment results demonstrate that the Acr+-Mes oxidase mimic shows higher affinity to 3,3′,5,5′-tetramethylbenzidine (TMB) than natural horseradish peroxidase or the reported molecule oxidase mimic. The reaction mechanism is ascribed to the strong oxidation property of the long-lived electron-transfer state (Acr•-Mes•+) and the electron transfer from Acr•-Mes radical to dissolved oxygen to generate superoxide radicals, which can easily oxidize various substrates. On the basis of these observations, the light-activatable Acr+-Mes with an oxidase-like activity as the probe is utilized for cost-effective, sensitive, and highly selective colorimetric detection of two biothiols (L-cysteine and L-glutathione). The lowest detectable concentrations of L-Cys and L-GSH is 100 nM, which is lower than that of most of the reported methods for biothiols. Beyond this, we construct a series of visual molecular logic gates (AND, INH, and NOR) using the oxidase mimic-involved reaction systems.
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IJS, KILJ, NUK, PNG, UL, UM
We report a molybdenum oxide (MoO
3
) nanomaterial-based three-input logic gate that uses Sn
2+
, NO
2
−
, and H
+
ions as inputs. Under acidic conditions, Sn
2+
is able to reduce MoO
3
nanosheets, ...generating oxygen-vacancy-rich MoO
3−
x
nanomaterials along with strong localized surface plasmon resonance (LSPR) and an intense blue solution as the output signal. When NO
2
−
is introduced, the redox reaction between the MoO
3
nanosheets and Sn
2+
is strongly inhibited because the NO
2
−
consumes both H
+
and Sn
2+
. The three-input logic gate was employed for the visual colorimetric detection of Sn
2+
and NO
2
−
under different input states. The colorimetric assay’s limit of detection for Sn
2+
and the lowest concentration of NO
2
−
detectable by the assay were found to be 27.5 nM and 0.1 μM, respectively. The assay permits the visual detection of Sn
2+
and NO
2
−
down to concentrations as low as 2 μM and 25 μM, respectively. The applicability of the logic-gate-based colorimetric assay was demonstrated by using it to detect Sn
2+
and NO
2
−
in several water sources.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Novel polyamide (PA) composite membranes were prepared by conducting interfacial polymerization on the modified carbon nanotube (mCNT)-deposited polyacrylonitrile (PAN) ultrafiltration membranes. ...Based on the characterization using TEM, SEM, FT-IR, and contact angle measurements, more even mCNT stacking could be realized on hydrolyzed PAN (hPAN) substrate. The uniformly stacked mCNT scaffold on hPAN is conducive to the formation of the PA composite membrane with a dense and crumpled texture. The prepared PA composite membrane exhibited dense crumpled texture with high hydrophilicity. The influences of surface morphology, feed temperature, and salt concentration and composition on desalination performances for PA composite membranes were investigated, followed by stability evaluation. Subjected to pervaporation desalination, the water flux attained to an ultrahigh value (104 kg m−2 h−1) with ideal rejection performance (99.99%) using 3.5 wt% NaCl aqueous solution as the feed at 70 °C. Moreover, the prepared PA composite membrane was also competent in hypersaline water desalination and acid brine water treatment. All the results demonstrated that the prepared PA composite membrane with crumpled texture had a great application potential in seawater desalination.
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•Carbon nanotube (CNT) was partially unzipped to form modified CNT (mCNT).•Polyamide composite membranes were prepared on mCNT-deposited polyacrylonitrile substrates.•Flux reached 104 kg m−2 h−1 with 99.99% rejection to 3.5 wt% NaCl solution at 70 °C.•Prepared composite membranes exhibited long-term stability with acid-resistant ability.•Prepared membranes were competent in hypersaline water desalination by pervaporation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The authors report on a fast chemiluminescence (CL) assay for the food additive sodium tripolyphosphate (STPP). It is based on the use of gold nanoflowers (AuNFs) bifunctionalized with luminol and ...chitosan that act as a CL probe and a molecular recognitions systems because chitosan can bind STPP. In the absence of STPP, the luminol-chitosan-AuNF CL system is triggered by addition of H
2
O
2
and Co(II) ions. However, on addition of STPP, modified AuNFs bind STPP and aggregate. This suppresses CL. Under optimized conditions, the system responds to STPP in the 0.7 to 700 μM concentration range, and the limit of concentration is as low as 0.5 μM. This is lower than that of other analytical techniques for STPP. The method was applied to the determination of STPP in (spiked) ham samples, and recoveries ranged from 98% to 107% with a relative standard deviation of <5.0%.
Graphical abstract
A fast chemiluminescent strategy is described for the detection of sodium tripolyphosphate (STPP). The method is based on the luminol-chitosan bifunctionalized gold nanoflower (AuNF)-H
2
O
2
-Co
2+
system. It can be completed within 7 min and is capable of detecting STPP in real samples such as commercial ham.
We report a single 9-mesityl-10-methylacridinium ion (Acr
+
-Mes) as a solvatochromic sensor array for multicolor visual discrimination of solvents. The composite fluorescent response of Acr
+
-Mes ...to polarity, dispersed state, and lone-pair-π interactions produces different colors when it is dissolved in various solvents. The corresponding RGB values as sensing elements are extracted to create distinct fluorescence response patterns for each solvent. With the help of principal component analysis, common solvents, such as water (H
2
O), absolute ethanol (EtOH), acetonitrile (MeCN), dimethyl sulfoxide (DMSO), acetone (CO(Me)
2
), dichloromethane (DCM), trichloromethane (TCM), tetrahydrofuran (THF), toluene (PhMe), and tetrachloromethane (CCl
4
), are successfully discriminated and identified with an accuracy of 100%. What's more, this sensor array can also discriminate binary solvent mixtures and quantitatively detect DMSO in organic and inorganic solvents.
We report a single 9-mesityl-10-methylacridinium ion (Acr
+
-Mes) as a solvatochromic sensor array for multicolor visual discrimination of solvents.
Logic systems that yield two or more signal outputs in the presence of the input are scarce. A universal logic system consisting of plasmonic MoO
3-x
nanodots and 3,3′-diaminobenzidine (DAB) for ...fabrication of visual contrary logic pairs and circuits are presented here. They do not require the use of expensive instrumentation but can be visually read. It is based on the facts that the blue dispersion of MoO
3-x
nanodots turns to colorless after oxidation, while the colorless reagent DAB is oxidized by various oxidants to generate a brown color. On this basis, the complete contrary logic pairs and circuits such as YES-NOT, AND-NAND, OR-NOR, XOR-XNOR, INH-IMH, and MAJ-MIN can be fabricated. Various oxidants serve as inputs, and absorbances as outputs. A smart logic voting system with “one-vote deny” function is also described that is based on the cascade of MAJ logic circuit and INH logic gate using ascorbic acid (AA) as the superior denier. All the logic operations can visually read due to the appearance of distinct color changes.
Graphical abstract
Schematic presentation of the contrary logic pairs and circuits using a visually and colorimetrically detectable redox system consisting of MoO
3-x
nanodots and 3,3′-diaminobenzidine.
