Liquid Chromatography-mass Spectrometry Techniques Research Articles

One-Pot Synthesis and <i>In Vitro</i> Studies of Calix[4]-2-methylresorcinarene Derivatives as Antimalarial Agents Against <i>Plasmodium falciparum</i> Chloroquine-Resistant Strain FCR-3

Malaria is an endemic disease in Indonesia caused by infection from the Plasmodium parasite. Recently, antimalarial resistance significantly contributed to the decline in the cure rate of malaria sufferers. In this work, three calix[4]resorcinarenes have been synthesized from 2-methylresorcinol and different benzaldehyde derivatives, i.e., 4-chlorobenzaldehyde, 4-methoxybenzaldehyde, and 4-dimethylaminobenzaldehyde through the one-pot synthesis procedure. The calix[4]resorcinarenes synthesis was done through a cyclo-condensation reaction by using HCl 37% as the catalyst and ethanol as the solvent in an one-pot reaction. The structures of the synthesized products were confirmed using Fourier transform infrared, proton-nuclear magnetic resonance, and liquid chromatography-mass spectrometry techniques. The antimalarial activity assay was evaluated against the Plasmodium falciparum FCR-3 strain through an in vitro study. Three synthesized compounds, i.e., C-4-chlorophenylcalix[4]-2-methylresorcinarene, C-4-methoxyphenylcalix[4]-2-methylresorcinarene and C-4-dimethylaminophenylcalix[4]-2-methylresorcinarene have been successfully synthesized in up to 97% yield. The C-4-chlorophenylcalix[4]-2-methylresorcinerene exhibited the most potent antimalarial activity with a half-maximal inhibitory concentration (IC50) value of 2.66 µM against P. falciparum FCR-3 while the C-4-methoxyphenylcalix[4]-2-methylresorcinarene and C-4-dimethylaminophenylcalix[4]-2-methylresorcinarene gave the IC50 values of 23.63 and 13.82 µM, respectively. From the results, it could be concluded that the antimalarial activity of calix[4]-2-methylresorcinarenes was influenced by the type of substituent of aromatic rings at the para position.

Non-targeted Screening and Ecological Risk Assessment of Emerging Contaminants in Beijiang Drinking Water Source of the Pearl River Delta

To investigate the spatial and temporal distribution characteristics and assess the ecological risks associated with emerging contaminants （ECs） in the Beijiang drinking water source, non-targeted screening was conducted using the ultra-high performance liquid chromatography-mass spectrometry technique （UPLC-MS） for one year （June 2022 to May 2023）. This study also involved the quantitative detection of eight typical ECs. The results showed that through the non-targeted screening, a total of 346 pollutants were identified, with industrial materials, pharmaceuticals, and pesticides being the predominant pollutants, collectively accounting for 88.2%. Concentrations of eight representative ECs ranged from n.d （undetected） to 180 ng·L-1, with detection rates exceeding 80% for six of them. Notably, higher concentrations were found in endocrine disruptors such as bisphenol A （BPA） and 4-nonylphenol （4-NP）, along with the pesticides atrazine （ATZ） and propisochlor （PPS）, with median concentrations ranging from 8.12 to 35.58 ng·L-1. The concentrations of ATZ, PPS, roxithromycin （ROX）, and ibuprofen （IBU） were significantly higher in the spring season compared to those in other seasons （P<0.05）. Elevated ecological risk levels （RQ>1） were observed at sampling point 1 （S1） and sampling point 3 （S3） for ATZ and Lomefloxacin （LOM）, while for 4-NP, it was determined to be high only at sampling site 2 （S2）. Given their high detection rates and ecotoxicity, particular attention should be paid to ATZ and 4-NP. The concentration level of ATZ exhibited significant seasonal variation due to its agricultural origin, so it is recommended to strengthen control during spring. Overall, this research provides critical insights into a comprehensive understanding of the presence and impact of ECs in this specific region.

BIOANALYTICAL METHOD DEVELOPMENT AND VALIDATION FOR THE DETERMINATION OF ASCIMINIB ANTICANCER DRUG IN BIOLOGICAL MATRICES BY LC–ESI-MS/MS

Objective: A unique liquid chromatography-mass spectrometry technique is essential for determining the concentration of asciminib in biological matrices, and its development is of the utmost importance. Methods: The samples that were processed were separated using a Reversed Phase-Phenomenex (100 mm x 4.6 mm, 5 µm) C18 analytical column. The column was equipped with an isocratic moveable phase that consisted of 0.1% (v/v) HCOOH and acetonitrile at a ratio of 18:82% (v/v). The flow rate of the phase was 0.70 ml/min. For asciminib, the multiple reaction monitoring mode was used at m/z 450.23/257.3, while for canagliflozin, it was used at m/z 445.13/267.31. Results: With a correlation coefficient of 0.9998, the method was linear for asciminib throughout the concentration range of 1.0-2100.00 ng/ml. Each day's accuracy percentage relative standard deviation was within 5.74%. For analytes at the low-quality control level, the mean matrix factors ranged from 96.34 to 104.85% with a % Coefficient of Variance (CV) of 4.21; at the high-quality control level, the range was from 94.62 to 103.88% with a %CV of 3.67. Conclusion: The method that has been developed has the potential to be used to examine the pharmacokinetics and toxicokinetics of asciminib in various biological samples for both forensic and clinical purposes.

LC-MS-Based Simultaneous Determination of Biomarkers in Dried Urine Spots for the Detection of Cofactor-Dependent Metabolic Disorders in Neonates.

Deficiency of cofactors for various enzymes can lead to inborn errors of metabolism. These conditions frequently occur as seizures, which lead to permanent brain damage. Newborn screening for biomarkers associated with these disorders can help in early detection and treatment. Our objective was to establish a liquid chromatography mass spectrometry technique for quantifying biomarkers in dried urine spots to detect specific vitamin-responsive inborn errors metabolism. Biomarkers were extracted from dried urine spots using a methanol:0.1% v/v formic acid solution (75:25) containing an internal standard mixture. Separation was achieved using a Luna PFP column (150mm×4.6mm, 3µm) under gradient elution conditions. The LC-MS technique was validated as per ICH M10 guidelines. Urine samples from healthy newborns in Udupi district, South India, were analyzed to establish reference values for these biomarkers. The method demonstrated excellent linearity (R2>0.99) with low limits of quantification: 0.1µg/mL for leucine, isoleucine, valine, proline, hydroxyproline, methylmalonic acid, and 3-hydroxyisovaleric acid; 0.01µg/mL for pipecolic acid and α-aminoadipic semialdehyde; and 0.03µg/mL for piperideine-6-carboxylate. Interconvertibility between urine and dried urine spot assays was observed from the results of the regression and Bland-Altman analyses. Reference intervals for these biomarkers in the Udupi neonatal population were established using the validated dried urine spot method.

Construction of 0-dimensional silver quantum dot/MoSe2@MXene/3-dimensional porous copper foam composite electrodes with heterogeneous interfaces for synergistic electrocatalytic degradation of antibiotics

This study proposes a novel and efficient Ag quantum dots (QDs)/MoSe2@two-dimensional transition metal carbide/nitride (MXene)/copper foam (CF) composite electrode to address the challenge of electrocatalytic degradation of antibiotics in water. The electrode formed a unique electron donor–acceptor system by loading Ag QDs and heterostructured nanosheets on CF, significantly facilitating charge transfer and segregation at the interface. The catalytically active sites at the edges and defective locations of MoSe2 in conjunction with the two-dimensional MXene structure, which formed an efficient electron transfer channel, promoted the electron transfer from the interior to the surface and accelerated the hydrogen adsorption and reduction reactions. Moreover, the charge redistribution at the interface of Ag QDs and MoSe2@MXene formed interfacial dipoles, increasing the active sites on the catalyst surface and promoting the generation of cathodic atomic hydrogen (H*). Under optimal conditions, the degradation rate of tigecycline (TGC) reached as high as 90.1 % ± 2.4 % within 60 min. The anode-generated OH and HClO, along with the cathode-generated H, further promoted the degradation of TGC through co-catalysis. The degradation pathways were analyzed using density-functional theory (DFT) calculations and liquid chromatography-mass spectrometry (LC-MS) techniques. Moreover, toxicity analysis of the degradation products was carried out to ensure the safety of the treated wastewater discharge. A reflux continuous effluent reactor was also designed to achieve high degradation efficiency and low energy consumption after stable operation, laying the foundation for industrial applications. This technology provides new ideas for the design of green, efficient, stable, and low-consumption electrocatalytic reactors and contributes to a sustainable future environment.

Comparative Evaluation of the Chemical Components and Anti-Inflammatory Potential of Yellow- and Blue-Flowered Meconopsis Species: M. integrifolia and M. betonicifolia.

Background/Objectives:Meconopsis has long been used in traditional Tibetan medicine to treat various inflammatory and pain-related conditions. However, blue-flowered Meconopsis (M. betonicifolia) is becoming increasingly scarce due to overharvesting. As a potential alternative, yellow-flowered Meconopsis (M. integrifolia) shows promise but requires comprehensive characterization. This study aimed to evaluate and compare the anti-inflammatory potential of yellow- and blue-flowered Meconopsis species. Methods: Liquid chromatography-mass spectrometry (LC-MS) techniques were used to analyze the chemical profiles of yellow- and blue-flowered Meconopsis. Putative targets of shared constituents were subjected to GO and disease enrichment analysis. The LPS-induced RAW264.7 macrophage model was employed to assess anti-inflammatory effects. Metabolomics was applied to gain mechanistic insights. Results: LC-MS revealed over 70% chemical similarity between species. Enrichment analysis associated targets with inflammation-related pathways. In macrophage assays, both species demonstrated dose-dependent antioxidative and anti-inflammatory activities, with yellow Meconopsis exhibiting superior efficacy. Metabolomics showed modulation of key inflammatory metabolic pathways. Conclusions: This integrative study validated yellow-flowered Meconopsis as a credible alternative to its blue-flowered counterpart for anti-inflammatory applications. Metabolic profiling provided initial clues regarding their multi-targeted modes of action, highlighting their potential for sustainable utilization and biodiversity conservation.

Introducing oxygen cacancies to tune Cu2O by Sn ion-doped for high-effective photocatalytic degradation of norfloxacin in wastewater

Photocatalytic materials have attracted considerable attention owing to its positive environmental impact and efficiency in wastewater treatment. Herein, tin (Sn)-doped copper oxide (Cu2O) photocatalysts were successfully synthesized via a facile hydrothermal approach. The doping of Sn ions into the Cu2O lattice promoted the formation of more oxygen vacancies, which increased the separation efficiency of photogenerated carriers and enhanced photocatalytic activity. Moreover, the presence of Sn ions enhanced light absorption and the specific surface area of Cu2O, and reduced photogenerated carriers recombination. The synergistic effect of the abovementioned advantages, induced excellent photocatalytic activity to the as-prepared catalysts. Tin chloride (30 mg)-doped Cu2O showed optimal photocatalytic properties with the highest norfloxacin degradation rate of 83.9 % in 140 min under visible light irradiation. Hydroxy radicals played a major role during degradation as demonstrated by the capturing of active species experiment and EPR testing. Photocatalytic mechanisms and possible degradation pathways were proposed based on Perdew-Burke-Ernzerhof and high-performance liquid chromatography-mass spectrometry techniques. The toxicity analyses of the intermediates proved their low toxicity. Repeated cycling experiments confirmed the excellent stability of the catalysts. This work provides a feasible strategy for fabricating high-performance Cu2O-based photocatalysts.

Mechanistic study on 4, 4'-sulfonylbis removal with CO2/Ar gas-liquid DBD plasma

In this study, a single dielectric barrier discharge (DBD) coaxial reactor was used to degrade 4, 4'-sulfonylbis (TBBPS) in water using greenhouse gas (CO2) and argon as the carrier gases. The investigation focused on CO2 conversion, reactive species formation, gas-liquid mass transfer mechanism, and degradation mechanism of TBBPS during the discharge plasma process. With the decrease of CO2/Ar ratio in the process of plasma discharge, the emission spectrum intensity of Ar, CO2 and excited reactive species was enhanced. This increase promoted collision and dissociation of CO2, resulting in a series of chemical reactions that improved the production of reactive species such as ·OH, 1O2, H2O2 and O3. These reactive species initiated a sequence of reactions with TBBPS. Results indicated that at a gas flow rate of 240 mL/min with a CO2/Ar ratio of 1:5, both the highest CO2 conversion rate (17.76%) and TBBPS degradation rate (94.24%) were achieved. The degradation mechanism was elucidated by determining types and contents of reactive species present in treatment liquid along with analysis of intermediate products using liquid chromatography-mass spectrometry techniques. This research provides novel insights into carbon dioxide utilization and water pollution control through dielectric barrier discharge plasma technology.

Comparative Metabolomics Analysis of 3 New Potato Varieties against the Atlantic Cultivar; Bioinformatics based Experimental Study

Background: Varietal differences in metabolite composition play a crucial role in determining agronomic traits, nutritional quality and stress resilience in Solanum tuberosum. Methods: Three potatoes varieties; Longshu 7, Longshu 10 and Longshu 14 were selected and bred by the at the Potato Research Institute of Gansu Academy of Agricultural Sciences between December 2021 to December 2023. Thereafter, comparative metabolomics analysis of three new potato varieties (LS7, LS10 and LS14) was undertaken against the well-established Atlantic cultivar. We employed a bioinformatics-based experimental approach to analyze the metabolomic data obtained from the three new potato varieties (LS7, LS10 and LS14) and the Atlantic cultivar. Metabolite profiling was performed using high-throughput liquid chromatography-mass spectrometry (LC-MS) techniques. Differential metabolite analysis and pathway enrichment analysis were conducted to identify significant metabolic differences and enriched pathways among the varieties. Result: Results revealed substantial differences in metabolite composition and pathway enrichment between the new potato varieties and the Atlantic cultivar. Metabolites involved in diverse metabolic pathways, including glucoside and hydroxyproline in LS7, kaempferol and ascorbic acid in LS10 and phenyl-butyryl-glutamine and ascorbic acid in LS14, exhibited significant upregulation or downregulation compared to the Atlantic cultivar. Pathway enrichment analysis highlighted the prominence of ABC transporters across all comparisons, suggesting their universal role in mediating cellular processes and stress responses in potato varieties. In conclusion, these findings contribute to our understanding of potato metabolism and pave the way for the development of novel breeding approaches to meet the evolving demands of global agriculture and food security.

Constructing cascade electric fields and sulfur vacancies in Ni3S4/NiS2/v-Zn3In2S6 photocatalyst for efficient degradation of contaminants and H2 production

The increasing environmental pollution and looming energy crisis necessitate the development of advanced photocatalysts that demonstrate efficient separation and transfer of the photo-generated holes and electrons, as well as multiple functions to address the above issues. Herein, a bifunctional Ni3S4/NiS2/v-Zn3In2S6 photocatalyst has been constructed to degrade environmental hormones and antibiotics with simultaneous H2 production. Sulfur vacancies have been engineered in the Zn3In2S6 from a kinetic point of view to accelerate the separation of photogenerated charge carriers and act as active sites. Ni3S4 and NiS2 are introduced to construct cascade electric fields with Zn3In2S6 via ohmic junctions for spatially separated charge carriers and reduced hydrogen evolution potential. As a result, the composite exhibits enhanced photocatalytic H2 production and efficient degradation of bisphenol A, norfloxacin, and tetracycline, respectively. Specifically, the degradation pathways of BPA have been investigated based on Fukui calculations and liquid chromatography-mass spectrometry techniques. This work may shed new light on the design and construction of dual-function photocatalysts for wastewater treatment and H2 production.

Metabolomic Profiles in Jamaican Children With and Without Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with a wide range of behavioral and cognitive impairments. While genetic and environmental factors are known to contribute to its etiology, metabolic perturbations associated with ASD, which can potentially connect genetic and environmental factors, remain poorly understood. Therefore, we conducted a metabolomic case-control study and performed a comprehensive analysis to identify significant alterations in metabolite profiles between children with ASD and typically developing (TD) controls in order to identify specific metabolites that may serve as biomarkers for the disorder. We conducted metabolomic profiling on plasma samples from participants in the second phase of Epidemiological Research on Autism in Jamaica, an age and sex-matched cohort of 200 children with ASD and 200 TD controls (2-8years old). Using high-throughput liquid chromatography-mass spectrometry techniques, we performed a targeted metabolite analysis, encompassing amino acids, lipids, carbohydrates, and other key metabolic compounds. After quality control and missing data imputation, we performed univariable and multivariable analysis using normalized metabolites while adjusting for covariates, age, sex, socioeconomic status, and child's parish of birth. Our findings revealed unique metabolic patterns in children with ASD for four metabolites compared to TD controls. Notably, three metabolites were fatty acids, including myristoleic acid, eicosatetraenoic acid, and octadecenoic acid. The amino acid sarcosine exhibited a significant association with ASD. These findings highlight the role of metabolites in the etiology of ASD and suggest opportunities for the development of targeted interventions.

Development and Validation of Stability Indicating Liquid Chromatographic Method for Vandetanib: Application to Degradation Studies by LC-MS

Objective: The central goal of this research was to formulate and validate a stability-demonstrating assay approach using reverse-phase high-performance liquid chromatography (RP-HPLC) for the assessment of vandetanib, its primary degradation products, and their respective degradation pathways, which were identified and characterized using liquid chromatography-electrophore spray ionization-mass spectrometry (LC-ESI-MS).Methods: The method was designed and developed by employing a Grace C18 column (250 x 4.6 mm x4.0 μm) and deploying a mixture of methanol and 0.1% formic acid in H2O (in a proportion of 90:10, v/v) as the mobile phase, with a flow rate maintained at 1-mL/min. The analytes were detected at a wavelength of 249 nm. Additionally, vandetanib was subjected to various stress conditions, including acidic, alkaline, oxidative, thermal, and photolytic degradation, to unearth the degradation paths for the principal degradation products.Results: The approach was meticulously formulated and validated to ensure robustness, linearity, precision, accuracy, and linear regression analysis data. A high correlation coefficient of 0.9985 was obtained in the 2 to 12 μg/mL concentration range, demonstrating a robust linear relationship. Moreover, the limit of detection (LoD) and the limit of quantification (LoQ) were found to be 0.166 and 0.503 μg/mL, respectively. In the stress degradation studies, we noticed that vandetanib degraded in alkaline and acidic mediums. The liquid chromatography-mass spectrometry (LC-MS) technique was used to characterize the degradation products.Conclusion: The devised method demonstrated itself to be quick, sensitive, precise, accurate, and robust for the vandetanib analysis, thereby facilitating its routine testing.

Data-independent acquisition combined with liquid chromatography mass spectrometry technique to detect prognostic protein markers in type I gastric neuroendocrine neoplasm.

This study used proteomics-based data-independent acquisition (DIA) technology with the aim of screening for differential expression proteins in type I gastric neuroendocrine neoplasm (g-NEN). Differential expression proteins in type I g-NEN and peritumoral tissues were screened using DIA with liquid chromatography/tandem mass spectrometry (DIA-LC/MS/MS). The identified proteins were then functionally analysed using bioinformatics methods. We selected the three most highly expressed proteins, combined with patients' clinical data, for prognostic analysis. Compared with peritumoral tissues, 224 proteins were up-regulated, and 70 were down-regulated. The most significantly enriched biological processes and pathways were vacuolar proton-transporting V-type ATPase complex assembly and metabolism-related pathways. PCSK1, FBXO2, ACSL1, IRS2, and PTPRZ1 expression was markedly up-regulated in type I g-NENs. High IRS2 expression significantly correlated with a shorter time to recurrence. Our study provides a comprehensive proteomic signature based on DIA-LC/MS/MS and highlights high IRS2 expression as a potential prognostic marker for type I gNENs.

Identification of Phenolic Compounds Present in Three Speedwell (Veronica L.) Species and Their Antioxidant Potential.

Extracts from Veronica species (speedwells) are known for the various biological activities they show, such as cytotoxic, antimicrobial, anti-inflammatory, and antioxidant activities. Also, the plants from this genus are known as medicinal plants used in traditional medicine worldwide. Phenolic compounds are specialized metabolites that contribute to biological activity the most. Therefore, the aim of this research is identification and quantification of phenolic compounds present in three Veronica species (Veronica anagallis-aquatica L., Veronica persica Poir., and Veronica polita Fr.) using the liquid chromatography-mass spectrometry (LC-MS/MS) technique. All extracts were tested for antioxidant activity with two methods: DPPH (2,2-diphenyl-1-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity). Also, standards for compounds that were detected in the highest amount in all species were also tested for antioxidant activity. Three different solvents (pure methanol, 80% ethanol, and water) were used for the extraction of phenolic components and their comparison in order to test their antioxidant activity as a final goal. The main compounds present in the tested Veronica extracts were: p-hydroxybenzoic acid, vanillic acid, caffeic acid, gentisic acid, and apigenin. V. anagallis-aquatica contained the highest amount of phenolic components in comparison with the two other tested species, V. persica and V. polita. Caffeic acid showed the highest antioxidant activity in both studied methods with an IC50 value for DPPH activity of 1.99 µg/mL. For the plant extracts, in general, methanolic/ethanolic extracts showed higher activity than water extracts in both methods which was expected, as organic solutions extract more phenolic compounds. This research points to the potential application of extracts of different Veronica species for antioxidant activity.

A novel peony-shaped ZnO/biochar nanocomposites with dominant {100} facets for efficient adsorption and photocatalytic removal of refractory contaminants

Herein, a peony-shaped nanocomposite (P-ZnO/BC) was facilely developed by incorporating ZnO with Hemp stalk derived biochar (BC) via two-step sequential solvothermal procedure and used for photocatalytic degradation of organic contaminants. The as-prepared P-ZnO/BC presents preferential (100) crystal orientation, suitable electronic energy level, and distinct mesoporous distribution as well as large specific surface area. Thereby, the optimal P-ZnO0.3/BC (weight ratio of 3:7 for ZnO:BC) shows higher photocatalytic activity with degradation efficiency as high as 94.5 % toward methylene blue (MB) within 120 min, whereas the ZnO and BC merely deliver 6.3 % and 63.5 %, respectively. Obviously, the superior contaminants removal properties of P-ZnO0.3/BC can be attributed to the synergistic effect of adsorption of BC and photocatalysis of ZnO. Also, this can be associated with the improved adsorption, accelerated charges (e-/h+ pairs) transportation and reduced e-/h+ pairs recombination of P-ZnO0.3/BC. The reactive radicals scavenging experiments and ESR measurements confirm that the main reactive species are hydroxyl radicals (•OH) and holes (h+). Furthermore, P-ZnO0.3/BC displays desirable reusability and better universal applicability toward other organic dyes and antibiotics removal. Moreover, the possible degradation mechanism and pathway were also inferred by analyzing the intermediates via liquid chromatography mass spectrometry (LC-MS) technique. In conclusion, this work provides a fundamental insight via integrating ZnO with low-cost BC for efficient removal of the refractory organic pollutants.

Antifungal mechanisms investigation of lactic acid bacteria against Aspergillus flavus: through combining microbial metabolomics and co-culture system.

To develop antifungal lactic acid bacteria (LAB) and investigate their antifungal mechanisms against Aspergillus flavus in aflatoxin (AF) production. We isolated 179 LABs from cereal-based fermentation starters and investigated their antifungal mechanism against Aspergillus flavus through liquid chromatography-mass spectrometry and co-culture analysis techniques. Of the 179 isolates, antifungal activity was identified in Pediococcus pentosaceus, Lactobacillus crustorum, and Weissella paramesenteroides. These LABs reduced AF concentration by i) inhibiting mycelial growth, ii) binding AF to the cell wall, and iii) producing antifungal compounds. Species-specific activities were also observed, with P. pentosaceus inhibiting AF production and W. paramesenteroides showing AF B1 binding activity. In addition, crucial extracellular metabolites for selecting antifungal LAB were involved in the 2',3'-cAMP-adenosine and nucleoside pathways. This study demonstrates that P. pentosaceus, L. crustorum, and W. paramesenteroides are key LAB strains with distinct antifungal mechanisms against A. flavus, suggesting their potential as biological agents to reduce AF in food materials.

Electron transfer mediated photo-Fenton-like synergistic catalysis of Fe,Cu-doped MIL-101 coupled with Ag3PO4: Quantitative evaluation and DFT calculations

Widespread use of tetracycline (TC) results in its persistent residue and bioaccumulation in aquatic environments, posing a high toxicity to non-target organisms. In this study, a bimetal-doped composite material Ag3PO4/MIL-101(Fe,Cu) has been designed for the treatment of TC in aqueous solutions. As the molar ratio of Fe/Cu in composite is 1:1, the obtained material AP/MFe1Cu1 is placed in an aqueous environment under visible light irradiation in the presence of 3 mM peroxydisulfate (PDS), which forms a photo-Fenton-like catalytic system that can completely degrade TC (10 mg/L) within 60 min. Further, the degradation rate constant (0.0668 min−1) is 5.66 and 7.34 times higher than that of AP/MFe and AP/MCu, respectively, demonstrating a significant advantage over single metal-doped catalysts. DFT calculations confirm the strong adsorption capacity and activation advantage of PDS on the composite surface. Therefore, the continuous photogenerated electrons (e−) accelerate the activation of PDS and the production of SO4•−, resulting in the stripping of abundant photogenerated h + for TC oxidation. Meanwhile, the internal circulation of FeⅢ/FeⅡ and CuⅡ/CuⅢ in composite also greatly enhances the photo-Fenton-like catalytic stability. According to the competitive dynamic experiments, SO4•− have the greatest contribution to TC degradation (58.93%), followed by 1O2 (23.80%). The degradation intermediates (products) identified by high-performance liquid chromatography-mass spectrometry (HPLC/MS) technique indicate the involvement of various processes in TC degradation, such as dehydroxylation, deamination, N-demethylation, and ring opening. Furthermore, as the reaction proceeds, the toxicity of the intermediates produced during TC degradation gradually decreases, which can ensure the safety of the aquatic ecosystem. Overall, this work reveals the synergy mechanism of PDS catalysis and photocatalysis, as well as provides technical support for removal of TC-contaminated wastewater.

Rapid analysis of the chemical constituents of traditional Tibetan medicine Sbyor-bzo-ghi-wang using ballpoint electrospray ionization technique.

The chemical constituents of traditional Tibetan medicines (TTM) can be identified using high-performance liquid chromatography and high-resolution mass spectrometry (HPLC-MS/MS) technique. However, the HPLC-MS/MS technique requires the sample to be pretreated and then separated using the specific liquid chromatography method, which is time consuming. This study developed a ballpoint electrospray ionization (BPESI) technique for analyzing the chemical constituents of Sbyor-bzo-ghi-wang. This technique is a simple and inexpensive method for the rapid identification of the chemical constituents of TTMs. After the important parameters of the homemade BPESI device were optimized, the chemical constituents of Sbyor-bzo-ghi-wang were quickly identified without sample pretreatment. The raw data were converted to mzML file using MSConvert and then identified using SIRIUS 5 software. The results showed that 30 compounds were identified from Sbyor-bzo-ghi-wang, namely eight bile acids, six flavonoids, four alkaloids, three amino acids, and nine others. Compared to the ultra-high-performance liquid chromatography-Q/Orbitrap and high-resolution mass spectrometry (UHPLC-Q/Orbitrap HRMS) technique, the BPESI technique identified almost similar types of compounds and also a comparable number of compounds. Compared with the traditional HPLC-MS/MS methods, the BPESI technique does not require complex sample pretreatment and subsequent chromatographic separation steps; also it consumes a small quantity of samples. Therefore, BPESI can be used for the qualitative analysis of the chemical constituents of Sbyor-bzo-ghi-wang.

Optical CuAl2O4 used as photocatalyst for IC dye degradation

ABSTRACT The nanocrystalline copper aluminate (CuAl2O4) has been successfully synthesized by a simple, economical, and environmentally friendly solid-state mechanochemical (MCH) method. The prepared sample was characterized by a variety of suitable methods employed, including scanning electron microscopy (SEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS), Fourier transform infrared spectroscopy (FT-IR), and X-ray powder diffraction (XRD). The material's average particle size was 55 nm and stoichiometric. CuAl2O4 has been found to exhibit potent photocatalytic activity toward indigo carmine (IC) when subjected to UV light. Under UV radiation, 10 mg CuAl2O4 leads to 99 ± 1% degradation of an 8 ppm IC dye solution among 2 ppm, 4 ppm, 6 ppm, 8 ppm, and 10 ppm in 25 min. In addition, a prospective liquid chromatography-mass spectrometry (LC-MS) technique is identified in the current work, which provides potential routes for the photocatalytic breakdown of IC. Even after five consecutive cycles, the photocatalyst showed remarkable reusability and stability.

Dissipation kinetics, dietary risk assessment and decontamination studies of tolfenpyrad in okra

QuEChERS method with liquid chromatography-mass spectrometry (LC-MS/MS) technique was employed for the estimation of tolfenpyrad residues in okra crop. The method was validated in terms of linearity, matrix effect, limit of quantification (LOQ), limit of detection, recovery, repeatability and reproducibility as per SANTE (2021) guidelines. After two applications of tolfenpyrad @150 (X), 187.5 (1.25X), 300 g a.i. ha−1 (2X), the mean initial residues were found to be 0.57, 0.78, and 1.21 mg kg −1. The residues reached below limit of quantification of 0.01 mg kg−1 after 10th, 15th, and 20th day at all the three doses, respectively. Dissipation kinetics of tolfenpyrad in okra was calculated to follow first order kinetics with half-life (T1/2) values of 2.10, 2.16, and 2.24 days at X, 1.25X and 2X dosages, respectively. Risk assessment in terms of hazard quotient (HQ) revealed that the application of tolfenpyrad was safe for safe consumption. Decontamination processes involved tap water wash, soaking in 2% salt solution, soaking in 2% salt solution along with boiling, soaking in 0.1% sodium bicarbonate solution, soaking in 0.01% potassium permanganate solution, boiling and frying. Frying followed by soaking in 2 per cent salt solution along with boiling proved to be highly effective in reducing tolfenpyrad residues by 80–85 and 76–79 per cent, respectively at all the three treatments.