UV Absorption Research Articles

Smart mathematically filtered UV spectroscopic methods for quality assurance of rosuvastatin and valsartan from formulation

Abstract Valsartan and rosuvastatin together in a binary form have been utilized to reduce hypertension and hyperlipidemia to control cardiovascular complications. This study depicts the simple three mathematically manipulated UV spectroscopic techniques for the estimation of rosuvastatin and valsartan in the formulation. The first method is simple UV absorption at 310 nm by RST and the first derivatization method for VTN. Determining the magnitude difference of a ratio spectrum at two identified wavelengths is the second approach, and determination of the magnitude of the first derivatives of the ratio spectra of RST and VTN constitute the third technique. The selection of wavelengths, divisor concentrations, and peak amplitudes were optimized and validated. The straight line was constructed in the range of 1–30 and 2–25 µg/ml for RST and VST by the normal and first derivatization method. By using the magnitude difference and magnitude of first derivative ratio spectra approaches, the concentrations of 1–12 and 2–25 µg/ml for RST and VTN, respectively, displayed a straight line. The limit of quantification was less than 1 µg/ml for RST and less than 2 µg/ml for VTN. It was eventually found that the accuracy, expressed as a percentage recovery, ranged between 98.94 and 99.55% for RST and 100.36 and 101.08% for VTN. The % RSD did not exceed 1.82 and 1.91 for RST and VTN, respectively. The three techniques were used to accurately measure RST and VTN in their binary formulations and physically mixed solutions, and the results were statistically compared to the previously published HPLC technique. The outstanding recovery achieved by using the authentic standard addition approach validated the methods’ supplemental accurateness. The Analytical Greenness and Red Green Blue procedures verified the eco-friendliness of the suggested UV spectroscopic approaches, which were also found to be superior to the documented HPLC methods.

A Turn‐On Fluorescence Probe Based on a New Salamo‐Co (II) Coordination Polymer for Tyrosine Detection and Its Application in Water Samples

ABSTRACTA novel salamo‐Co (II) coordination polymer probe CP was synthesized firstly, and its crystal structure, [Co3(L)2(PTA)(H2O)2]n·4nDMF, was determined by X‐ray diffraction analysis. The probe has a rare aggregation‐induced luminescence enhancement (AIEE) effect. When applied to amino acid detection, it was found to have a high selective recognition of tyrosine. With the increase of tyrosine, the fluorescent strength of the probe was enhanced in a short period of time. In addition, the binding ratio of probe to Tyr was determined by fluorescence titration experiment, and the detection limit LOD of probe CP for Tyr was calculated to be 2.57 × 10−9 M, and the binding constant Ka was 2.96 × 105 M−1. According to UV absorption spectrum, FT‐IR spectra, ESI mass spectrometry, and DFT calculation, it was speculated that Tyr can bind to the probe after adding Tyr into the probe solution, triggering FRET and ICT effects, resulting in increased fluorescence intensity and blue shift, and finally achieving the specific recognition of tyrosine by probe CP. Finally, the practical application of probe CP was studied. Through strip test and real water sample test, it was found that the probe can be used for qualitative and quantitative analysis of tyrosine.

Molecularly and Structurally Designed Polyimide Nanofiber Radiative Cooling Films for Spacecraft Thermal Management

AbstractRadiative cooling films (RCFs) are crucial for spacecraft thermal management, but their optical performance is currently limited by their structures and intrinsic high absorption at short wavelengths. In this study, a novel RCF using electrospun polyimide nanofibers optimized at both the molecular and microscale levels is developed. The newly designed polyimide molecules significantly decrease visible and ultraviolet (UV) light absorption while maintaining excellent thermal radiation properties in the infrared spectrum. By optimizing the diameter and orientation of the nanofibers using Monte Carlo simulations, the resulting film achieves a solar reflectivity of 99.6% and a mid‐infrared emissivity of 0.93. Its physical structures and optical properties remain stable under exposure to UV light, atomic oxygen, and extreme temperature changes. Further vacuum radiative cooling tests reveal that the thermal equilibrium temperature of this film is approximately 28 °C lower than that of Kapton‐based RCFs currently used in spacecraft. These results provide a new approach for creating efficient thermal management materials for space applications, with potential for broader use in architecture, electronic devices, and outdoor equipment.

The substantial generation of photochemically produced reactive intermediates (PPRIs) in algae-type zones from one large shallow lake promoted the removal of organic pollutants

Photochemically produced reactive intermediates (PPRIs) are ubiquitously present in aquatic systems and hold significant importance in biogeochemical cycles. The photochemical reaction of dissolved organic matter (DOM), known as photosensitizers upon irradiation, is the main pathway for PPRIs generation. However, the PPRIs produced by algal-derived organic matter (ADOM) and their environmental effects remains elusive. This study confirmed that substantial PPRIs were generated by ADOM in the algal-derived areas. UV absorption spectra, fluorescence spectra and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were then indicated a significant correlation between the molecular weight of DOM and the quantum yield of PPRIs, with lower molecular weight of DOM exhibiting a higher potential for PPRIs generation. Orthogonal partial least squares (OPLS) were used to build novel multivariate predictive models for indicating the PPRIs production in algae-type zone. Also, the higher concentrations of PPRIs could significantly removal different kinds of organic pollutants, such as bisphenol A (BPA), sulfadiazine (SDZ) and 17α-ethinylestradiol (EE2). Quenching experiments further elucidated that 3DOM⁎ was the key specie for pollutants degradation, serving as the precursor to generate a series of PPRIs. This study highlighted the importance of PPRIs generated from ADOM in the natural attenuation of pollutants and provided a new insight for understanding the self-purification in aquatic system.

Synthesis, cytotoxicity, docking, MD simulation, drug-likeness, ADMET prediction and multi spectroscopic studies of some novel quinoline-4-carboxamide derivatives as DNA intercalating and anticancer agents

In this study, some new quinoline-carboxamide derivatives possessing a flexible (dimethylamino) ethylcarboxamide side chain were synthesized as DNA intercalating agents. Synthesized compounds displayed potent cytotoxic activities against three human cancer cell lines including colorectal adenocarcinoma cancer cells (HT-29), breast cancer cells (MCF-7) and lung cancer cells (A549). Compound 3d showed promisingantiproliferative activity (IC50= 3.97 to 6.67 µM) against cancer cells. The simplest compound (compound 3a) without substitution displayed the weakest cytotoxic effects ranging from 24.6 to 42.3 μM. The interaction of the most cytotoxic compound 3d with calf thymus DNA (ctDNA) was evaluated by fluorescence, UV absorption, resonance light scattering (RLS), melting studies, viscosity measurements, circular dichroism (CD) spectroscopy, molecular docking and molecular dynamic (MD). Generally, studies displayed a combined quenching via intercalating binding mode of compound 3d to ctDNA.

Biosynthesis of Iron Oxide Nanoparticles by Marine Streptomyces sp. SMGL39 with Antibiofilm Activity: In Vitro and In Silico Study

One of the major global health threats in the present era is antibiotic resistance. Biosynthesized iron oxide nanoparticles (FeNPs) can combat microbial infections and can be synthesized without harmful chemicals. In the present investigation, 16S rRNA gene sequencing was used to discover Streptomyces sp. SMGL39, an actinomycete isolate utilized to reduce ferrous sulfate heptahydrate (FeSO4.7H2O) to biosynthesize FeNPs, which were then characterized using UV–Vis, XRD, FTIR, and TEM analyses. Furthermore, in our current study, the biosynthesized FeNPs were tested for antimicrobial and antibiofilm characteristics against different Gram-negative, Gram-positive, and fungal strains. Additionally, our work examines the biosynthesized FeNPs’ molecular docking and binding affinity to key enzymes, which contributed to bacterial infection cooperation via quorum sensing (QS) processes. A bright yellow to dark brown color shift indicated the production of FeNPs, which have polydispersed forms with particle sizes ranging from 80 to 180 nm and UV absorbance ranging from 220 to 280 nm. Biosynthesized FeNPs from actinobacteria significantly reduced the microbial growth of Fusarium oxysporum and L. monocytogenes, while they showed weak antimicrobial activity against P. aeruginosa and no activity against E. coli, MRSA, or Aspergillus niger. On the other hand, biosynthesized FeNPs showed strong antibiofilm activity against P. aeruginosa while showing mild and weak activity against B. subtilis and E. coli, respectively. The collaboration of biosynthesized FeNPs and key enzymes for bacterial infection exhibits hydrophobic and/or hydrogen bonding, according to this research. These results show that actinobacteria-biosynthesized FeNPs prevent biofilm development in bacteria.

Interactions with peanut protein isolate regulate the bioaccessibility of cyanidin-3-O-glucoside: Multispectral analysis, simulated digestion, and molecular dynamic simulation

Anthocyanins are susceptible to degradation owing to environmental factors. Combining them with proteins can improve their stability; however, the interaction mechanism is difficult to elucidate. This study used multispectral and molecular dynamics simulations and molecular docking methods to investigate the interaction mechanism between peanut protein isolate (PPI) and cyanidin-3-O-glucoside (C3G). The UV absorption peak and PPI turbidity increased, while the fluorescence intensity decreased with greater C3G content. Protein secondary structure changes suggested that PPI and C3G coexisted in spontaneous covalent and non-covalent interactions via static quenching. The complex structures were stable over time and C3G stably bound to the peanut globulin Ara h 3 cavity through hydrogen bonding and hydrophobic interactions. Furthermore, PPI enhanced the C3G antioxidant activity and bioaccessibility by increasing its retention rate during in-vitro simulated digestion. This study elucidates the binding mechanism of PPI and C3G and provides insight into applications of the complex in food development.

Far-UVC (UV222) based photolysis, photooxidation, and photoreduction of chlorophenols using a KrCl-excimer lamp: Degradation, dechlorination, and detoxification

The KrCl-excimer lamp, emitting far-UVC light at 222 nm (UV222), offers a promising alternative to conventional UVC light at 254 nm (UV254) for the photolysis of organic pollutants and the activation of radical sensitizers. This study was aimed to investigate the efficiencies of UV222 in the treatment of halogenated aromatics, focusing on its performance in degradation, dechlorination and detoxification. Chlorophenols, representative recalcitrant and toxic halogenated aromatics, were used as target pollutants. The pathways of direct photolysis, photooxidation and photoreduction under UV222 illumination were compared. UV222 outperformed UV254 in photolyzing chlorophenols (1.4−34.1 times faster), especially protonated chlorophenols, due to substantially higher UV absorption (17.1−108.0 times) and quantum yields (2.1−3.4 times). The quantum yields of chlorophenols were influenced by the inducive electron-withdrawing effect of Cl-substitutes. Moreover, UV222 improved the dechlorination of chlorophenols to 95 % compared to 60 % by UV254. The introduction of radical sensitizer (e.g., H2O2, nitrate, and sulfite) reduced 4-chlorophenol photolysis by competing for UV222 absorption, though the sensitizers partially increased radical oxidation via generating •OH or eaq−. UV222 photolysis of 4-chlorophenol increased the toxicity by 88.6 times through forming toxic intermediates (e.g., hydroquinone and resorcinol). Notably, •OH and eaq− (i.e., UV222/H2O2 and UV222/sulfite) increased the dechlorination and •OH (i.e., UV222/H2O2) detoxified the mixture solution. Moreover, UV222 photolysis remained effective for 4-chlorophenol removal in real paper-mill wastewater, indicating the potential application of KrCl* lamp UV222.

Engineering Macrophage-Derived Exosome to Deliver Pirfenidone: A Novel Approach to Combat Silicotic Pulmonary Fibrosis.

Silicosis is a severe lung disease characterized by diffuse pulmonary fibrosis, for which there is currently no effective treatment. Pirfenidone (PFD) shows great antifibrotic potential but is clinically hindered by low bioavailability and gastrointestinal side effects. To address these limitations, this study develops a PFD delivery system (PFD-Exo) using J774A.1 macrophage-derived exosomes. Firstly, PFD is loaded via sonication, then PFD-Exo is characterized using Raman spectral imaging and UV absorption spectroscopy. Finally, in vitro and in vivo silicosis models are established to evaluate its antifibrotic effects. Results show that PFD-Exo outperforms free PFD in inhibiting TGF-β1-induced transdifferentiation of primary lung fibroblasts in vitro. In a mouse model of silicosis, PFD-Exo is found to be accumulated in the lungs following intratracheal administration and significantly ameliorates pulmonary inflammation and fibrosis while minimizing gastrointestinal side effects. Mechanistic studies reveal that PFD-Exo modulates the TGF-β signaling pathway by downregulating SMAD3 and upregulating SMAD7 and NOGGIN. In conclusion, this study provides the first evidence of macrophage-derived exosomes as an effective PFD delivery system for silicosis treatment and offers a promising strategy for other refractory pulmonary diseases.

Overcoming the Strong Sample Solvent Effect for Sustainability Measurement Challenges in Liquid Chromatography. Example for Bisphenol-A.

This paper describes an approach to achieve low parts per billion (ppb) concentration level detection using a reversed-phase ultrahigh-performance liquid chromatographic ultraviolet absorbance detection method with large-volume feed injection (FI) for analytes in dichloromethane (DCM). FI is a novel technology that allows sample injection at a defined speed into the LC mobile phase. We demonstrate this approach for a mixture of bisphenol A and its diglycidyl ether derivatives in DCM. DCM is a very strong injection solvent at reversed-phase LC conditions and is typically immiscible with a starting reversed-phase gradient mobile phase containing a high percentage of water. As a result, reduced separation performance and even peak splitting are seen with classic flow-through injection. The method setup comprised an octyl-bonded core-shell stationary phase (150 × 4.6 mm i.d., 2.7 μm particle size) with a water/acetonitrile mobile phase gradient and an exceptionally high injection volume of 45 μL of DCM solution using FI. Optimization of feed speed (1%) and isocratic hold duration (4 min) was crucial for final separation conditions. FI delivered more than a 20-fold improvement in the limit of detection (LOD) compared to standard flow-through injection while maintaining peak resolution. The LOD of the final method ranged between 1 and 10 ppb in the polymer resin. This methodology has high potential for trace analysis in a large variety of applications that suffer from the "strong solvent effect".

A simplified tutorial on charged aerosol detection: Understanding the basics, optimization, and troubleshooting

The charged aerosol detector (CAD) measures the overall charge deposited on aerosolized particles to produce a signal proportional to the mass of analyte present, which applies to compounds with or without a chromophore. A significant benefit of CAD is the ability to quantitate a wide range of non-volatile compounds in absence of their authentic standards due to uniform response factor for such analytes. CAD is also a valuable tool to help detect and/or quantitate compounds with poor or no UV absorption. These can include salts, impurities, and a variety of other types of analytes.In this tutorial, fundamental principles of CAD and its utilization, troubleshooting, and maintenance will be demonstrated to ensure proper CAD usage. Successful operation of CAD includes optimizing power function value (PFV) to allow for a broader dynamic range and improve uniformity of response. The use of an inverse gradient (admixed post-column) enables more accurate quantitation, when employing a gradient analysis method. Several troubleshooting strategies, including diagnosing inverse gradient pump organic solvent delivery and determining volume match/mismatch between the inverse gradient and system pumps, will be presented along with important aspects of operating a CAD. Lastly, ensuring reliable results involves monitoring the performance of CAD over time to understand whether it is working sufficiently or if maintenance is required.

A Carbazole-based Fluorescent Probe with AIE Performance and a Large Stokes Shift for Peroxynitrite Detection and Imaging in Live Cells.

A carbazole-based fluorescent probe YCN with AIE performance and a large Stokes shift (242nm) shift was synthesized by attaching 4-acetonitrile pyridine to the 3-phenylaldehyde butylcarbazole. Its structure was characterized by 1H NMR, 13C NMR and MS. Probe YCN has high selectivity and sensitivity toward ONOO-. The addition of ONOO- to the probe YCN solution results in a noticeable color change from pale yellow to colorless under natural light, and a fluorescent color change from bright orange-yellow to bright yellow-green under a 365nm UV lamp, which can be distinguished by the naked eye. The research results on the reaction mechanism showed that when YCN reacted with ONOO-, -C = C- was oxidized and broken into -CHO, and the ICT effect was significantly inhibited, resulting in changes in UV absorption and fluorescence emission phenomenon. The recognition mechanism was verified by 1H NMR, mass spectrometry (MS) and density function theory (DFT) calculations. The experiments of live cells imaging suggested that compound YCN can be used as a fluorescent probe for the detection of ONOO- in HeLa cells. This result indicates that YCN has potential application prospects in the biological aspects.

Assessment of the impact of microwave roasting on nutrient content, lipid profile, and oxidative stability of pomegranate seed oil

The pomegranate, Punica granatum L. (Punicaceae), stands as one of the most widely employed oils in the cosmetic industry. However, due to its higher content of conjugated linoleic acid, its susceptibility to oxidation is a major challenge, with the most prominent being punicic acid. This study aimed to evaluate the effects of traditional roasting in a microwave on the lipid content, nutritional value, and oxidative stability of Moroccan pomegranate seed oil. The findings indicated a rise in the amount of oil after 15 min of roasting at 650 W, the amount of oil rose from 27.03 to 30.10 (g/100 g). However, the protein content, UV absorbance values, iodine, and saponification values were not significantly affected by a longer roasting time. The peroxide value increases with roasting (1.00 to 5.00 M.eq. O2/kg oil). The roasting process under 350 W did not significantly alter the fatty acid composition. The total tocopherol content exhibits a decrease with increasing roasting time and power, ranging from 333.36 mg/100 g for unroasted seeds to 316.84 mg/100 g for seeds roasted under the conditions of 650 W for 15 min. The roasting process has proven to be critical for the immediate and long-term preservation of the nutritional and physico-chemical properties of pomegranate seed oil.

Improved body and interface properties of EPDM insulation for HVDC cable accessory by grafted voltage stabilizer

As a key component in HVDC cable accessory, EPDM insulation is prone to breakdown both in body and along interface. To improve the comprehensive electrical strength of EPDM, voltage stabilizer 2-propenyl-4,6-dibenzoylresorcinol (ADR) was simultaneously grafted onto macromolecules through free radical reaction on its vinyl during crosslinking of EPDM. After modification, the mechanical strength and thermal stability of EPDM are improved. In terms of body properties, the injection and rapid transfer of space charge under normal electric field are weakened, the volume conductivity is reduced, the breakdown strength is improved and the growth of electrical tree is suppressed. In terms of interface properties, the normal electric field at the EPDM/XLPE interface is weakened, hence reduced potential risk of deterioration initiated from interface. Moreover, the surface conductivity of EPDM is reduced, the charge accumulation and migration along the EPDM/XLPE interface are suppressed, and the interface breakdown strengths under different interface pressures are significantly increased under tangential electric field. Molecular simulations and UV absorption characteristics indicate that the grafted ADR molecules not only introduce charge traps into EPDM, but also absorb the high energy from trapped electrons and consume it through multiple excitations, thus preventing the electron avalanche and subsequent degradation of EPDM.

Diffuse interstellar bands as dust indicators: The contribution from 3D maps

Three-dimensional (3D) distributions of the 862 nm diffuse interstellar band (DIB) carrier have been computed based on Gaia parallaxes and DIB catalogues, in parallel with 3D maps of dust extinction density. Three-dimensional maps provide local diagnostics and information on the distribution of structures in addition to line-of-sight (LOS) integrated quantities, and allow us to focus on poorly studied low-extinction areas. They make cross-matching with other catalogues possible through estimates of the DIB and extinction along any given path. We re-examined the relationships between the density of DIB carriers and the absorption and emission properties of spatially co-located dust. Along with laboratory identifications of carriers, these properties may shed light on the formation and evolution of this organic matter. They may also help to model dust emission and absorption properties in a more detailed way. We used the 3D maps of 862 nm DIBs and of dust extinction, as well as available DIB equivalent width (EW) catalogues and published measurements of parameters characterizing the dust extinction law and the dust emission. We studied the relationships between the extinction-normalized 862 nm DIB EW and the extinction level, the total-to-selective extinction ratio $R_V$, and the dust far-IR emission spectral index beta . We re-visited the link between several DIBs and the UV absorption bump at 220 nm. The ratio of the 862 nm DIB carrier density to the optical extinction density (DIB$_ norm $) is increasing in low-density clouds, confirming with local values the trend seen in the LOS data. In both cases, the coefficients of a fitted power law fall within the range of those measured towards SDSS high-latitude targets for 20 different bands, ranking this DIB among those with a high increase, above that of the broad 4430 DIB. This is consistent with the recent measurement of a larger scale height above the Plane for the 862 nm DIB compared to that of the 4430 DIB. Using map-integrated 862 nm DIB EWs and extinctions along the paths to APOGEE targets with published proxies $R'_V$ for the total-to-selective extinction ratio, we found that, despite a large scatter, DIB$_ norm $ is positively correlated with $R'_V$ for those stars with low to moderate extinctions ($A_V$= 0.2 to 2--3 mag). Independently, using stars from the 862 nm DIB catalogue located outside the disk and for the same regime of extinction, DIB$_ norm $ is found to be globally anti-correlated with the Planck opacity spectral index beta . This is consistent with the observed anti-correlation between beta and $R'_ V $. In the light of a recent result on the variability of the carbon/silicate ratio in dust grains as a source of this anti-correlation, it suggests that DIB$_ norm $ increases with the fraction of carbonaceous to silicate grains in the co-located dust, in agreement with the carbonaceous nature of DIB carriers and recent evidences for a spatial correlation between DIB$_ norm $ and the fluxes of carbon-rich ejecta of asymptotic giant branch (AGB) stars. At higher extinction both trends disappear, and there is evidence for a trend reversal. Regarding the link between the height of the 220 nm UV absorption bump and extinction-normalized EWs of DIBs, we found that two factors explain the absence of previous clear results: the correlation disappears when we move from sigma -type to zeta -type DIBs and/or from single-cloud LOSs to paths crossing multiple clouds distant from each other; zeta -type bands can be used to predict low and high values of the bump height, provided one adds a correcting factor linked to the ambient radiation field (e.g. the 5780/5797 DIB ratio). We show examples of simple models of the bump height based on the 5780 band, the 5850 band and the 5780/5797 DIB ratio. We also found an anti-correlation between DIB$_ norm $ and the width of the bump, which similarly disappears from sigma -type to zeta -type DIBs. This suggests that a fraction of the bump is generated outside the dense molecular clouds. There are complex relationships between DIBs and dust; however, massive measurements of DIBs and extinction and the derived 3D maps may provide some constraints on the density, the nature, and the contribution to extinction and emission of the co-located dust. This requires large stellar spectroscopic surveys and space-based measurements of UV extinction.

Photocatalytic removal of aldrin and dieldrin using graphene oxide and TiO2‐doped CuFe2O4

AbstractBACKGROUNDConventional treatment processes and existing photocatalysts have proven insufficient in efficiently removing aldrin and dieldrin. Consequently, this study aimed to investigate the removal of aldrin and dieldrin from surface water using a titanium dioxide/graphene oxide/copper ferrite (TiO₂/GO/CuFe₂O₄) nanocomposite.RESULTSThe highest photodegradation efficiencies for aldrin (100%) and dieldrin (99%) were achieved with a TiO₂/GO/CuFe₂O₄ nanocomposite dosage of 1.3 mg L−1, at a sunlight intensity of 9 W m−2 and an optimal photodegradation time of 25 min. The maximum UV absorption wavelength of the TiO₂/GO/CuFe₂O₄ nanocomposite was observed at 365 nm. The quantum yield of the nanocomposite was recorded as 2.69 × 102 mol einstein−1, and its bandgap energy was determined to be 3.31 eV. The first‐order kinetic rate constants for aldrin and dieldrin were calculated as 0.05 and 0.047 min−1, respectively. X‐ray diffraction analysis confirmed the crystal structure of CuFe₂O₄/TiO₂, while Fourier transform infrared spectroscopy detected carboxylic, epoxy, carbonyl and other oxygenated groups within the TiO₂/GO/CuFe₂O₄ nanocomposite. Scanning electron microscopy and transmission electron microscopy images revealed that CuFe₂O₄ was situated on the outer layer of GO. Energy‐dispersive X‐ray analysis identified the elemental composition of the TiO₂/GO/CuFe₂O₄ nanocomposite as comprising GO, C, Cu, Fe, Ti and O. A reusability study demonstrated that the nanocomposite maintained excellent performance, achieving 99% removal efficiency after 79 cycles and 97% after 100 cycles.CONCLUSIONSThe TiO₂/GO/CuFe₂O₄ nanocomposite effectively removed aldrin and dieldrin from surface water. This nanocomposite holds promise for the remediation of other aquatic ecosystems, such as bays, rivers and ocean waters. © 2024 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Distribution characteristics and sources of ultraviolet absorbents in facility agricultural soils in China

The environmental contamination of ultraviolet absorbents (UVAs) has attracted global attention for the persistence, bioaccumulation and ecotoxicity. However, little is known about the content and distribution characteristics of UVAs in agricultural soils, especially in facility agricultural soils. In this study, the contents and distribution characteristics of 16 UVAs were surveyed in agricultural facility soils (N = 61) and field soil samples (N = 61) from 27 provinces in China. The total content of 16 UVAs (Σ16UVAs) in facility soils (mean 64.2 ± 55.4 ng/g) was higher than that in field soils (mean 9.66 ± 7.66 ng/g), suggesting that UVAs in facility soils are associated with mulch film. The Σ16UVAs content in the soil mulched with biodegradable (PBAT) film was higher than that in the soil mulched with polyethylene (PE) film, which indicated that the UVA pollution in the soil mulched with biodegradable film was more serious. With the continuous promotion of the use of biodegradable films may pose a threat to soil and ecological health. Therefore, studies on the content and distribution characteristics of UVAs in facility soils are needed to provide scientific basis for the controlling and monitoring of novel pollutants.

A highly sensitive dual-mode detection platform based on the novel copper/molybdenum bimetallic nanoclusters and Co–Fe layered doubled hydroxide nanozyme for butyrylcholinesterase activity sensing

Herein, a novel copper/molybdenum bimetallic nanoclusters (Cu/Mo NCs) with intense blue emission were synthesized by using polyvinylpyrrolidone (PVP) as template and ascorbic acid as reducing agent. Owing to the synergistic effect between Cu and Mo, the fluorescence intensity of Cu/Mo NCs was significantly improved about 6-time than monometallic copper nanoclusters. A novel and sensitive ratiometric fluorescence and colorimetric dual-mode sensing platform for monitoring butyrylcholinesterase (BChE) was strategically constructed by the integration of Cu/Mo NCs with excellent optical properties and Co–Fe layered doubled hydroxide (CoFe-LDH) with superior peroxidase-like activity for the first time. In the presence of H2O2, nonfluorescent and colorless o-phenylenediamine (OPD) was oxidized to fluorescent and yellow 2,3-diaminophenazine (DAP) with maximum fluorescence emission peak at 564 nm and ultraviolet absorption peak at 418 nm by CoFe-LDH with peroxidase-like activity. Simultaneously, the generation of DAP could effectively quench Cu/Mo NCs fluorescence at 444 nm through the inner-filter effect (IFE). The hydrolysis of S-butyrylthiocholine iodide (BTCh) can be catalyzed by butyrylcholinesterase (BChE) to generate thiocholine (TCh) that could hinder the oxidation of OPD, leading to the fluorescence and ultraviolet absorption of DAP decreased, meanwhile, the fluorescence of Cu/Mo NCs recovered. The ratiometric fluorescence signal F564/F444 and colorimetric system both performed a satisfactory response to the concentration of BChE in the range 0.5 to 90 U L−1 and 1 to 100 U L−1 with the LOD of 0.18 U L−1 and 0.36 U L−1, respectively. The dual-mode sensing for BChE exhibited outstanding application potential in biosensing.

Acoustoelectric Effect due to an In-Depth Inhomogeneous Conductivity Change in ZnO/Fused Silica Substrates

The acoustoelectric (AE) effect induced by the absorption of ultraviolet (UV) light at 365 nm in piezoelectric ZnO films was theoretically and experimentally studied. c-ZnO films 4.0 µm thick were grown by the RF reactive magnetron sputtering technique onto fused silica substrates at 200 °C. A surface acoustic wave (SAW) delay line was fabricated with two split-finger Al interdigital transducers (IDTs) photolithographically implemented onto the ZnO-free surface to excite and reveal the propagation of the fundamental Rayleigh wave and its third harmonic at about 39 and 104 MHz. A small area of a few square millimeters on the surface of the ZnO layer, in between the two IDTs, was illuminated by UV light at different light power values (from about 10 mW up to 1.2 W) through the back surface of the SiO2 substrate, which is optically transparent. The UV absorption caused a change of the ZnO electrical conductivity, which in turn affected the velocity and insertion loss (IL) of the two waves. It was experimentally observed that the phase velocity of the fundamental and third harmonic waves decreased with an increase in the UV power, while the IL vs. UV power behavior differed at large UV power values: the Rayleigh wave underwent a single peak in attenuation, while its third harmonic underwent a further peak. A two-dimensional finite element study was performed to simulate the waves IL and phase velocity vs. the ZnO electrical conductivity, under the assumption that the ZnO layer conductivity undergoes an in-depth inhomogeneous change according to an exponential decay law, with a penetration depth of 325 nm. The theoretical results predicted single- and double-peak IL behavior for the fundamental and harmonic wave due to volume conductivity changes, as opposed to the AE effect induced by surface conductivity changes for which a single-peak IL behavior is expected. The phenomena predicted by the theoretical models were confirmed by the experimental results.

Three spectrophotometric quantitative analysis of bisoprolol fumarate and telmisartan in fixed-dose combination utilizing ratio spectra manipulation methods

Hypertension is a chronic condition with multiple drug regimens. Limiting these medicines is critical to patient compliance. Therefore, bisoprolol and telmisartan were recently developed in a fixed-dose combination to control blood pressure. The UV absorption spectra of bisoprolol and telmisartan overlapped significantly. Thus, three spectrophotometric methods have been developed for simultaneous determination of bisoprolol and telmisartan without prior separation. Method A is ratio difference of ratio spectra (RD), which measures the amplitude difference between (210–224) nm for bisoprolol and between (255–365) nm for telmisartan. Method B, the first derivative of ratio spectra (1DD), measures amplitude signals at 232 and 243 nm for bisoprolol and telmisartan, respectively. Method C is the mean centering of ratio spectra (MC), which measures the mean-centered ratio spectra's values at 223 nm for bisoprolol and 245 nm for telmisartan. The applied methods showed good linearity 2–20 µg/mL for bisoprolol, 4–32 µg/mL for telmisartan, with sufficient accuracy and precision. The methods were sensitive, with LOD values of 0.243 µg/mL and 0.596 µg/mL in RD method, 0.313 µg/mL and 0.914 µg/mL in 1DD method, and 0.406 and 0.707 µg/mL in MC method for bisoprolol and telmisartan, respectively, the methods were validated per ICH criteria. The novel methods are precise and accurate and can be used for routine analysis and quality control of bisoprolol and telmisartan in pure and dosage form. Furthermore, the greenness of the approaches was evaluated using Analytical Greenness assessment (AGREE), and the suggested method received a high greenness score.