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A green, sensitive and rapid spectrofluorimetric method for quantitative assay of an anti-allergic medication composed of montelukast and fexofenadine mixture in raw materials and dosage form was developed. The method was based on measuring the synchronous fluorimetric peak without interference, pre-separation or pre-extraction procedures. Montelukast was analyzed at 360 nm while fexofenadine was measured at 263 nm using Δλ = 20 nm for both drugs using ethanol as diluting solvent and acetate buffer of pH 4. The assay was rectilinear over the concentration range of 1.0-10.0 μg/mL for fexofenadine and 0.1-0.6 μg/mL for montelukast. The method was full validated according to ICH guidelines. The applicability of the method enables the assay of both drugs in raw materials, synthetic mixture as well as combined tablets. Moreover, the greenness of the method was assessed using different methods including; analytical eco-scale, GAPI and AGREE. All of these methods confirm that the proposed method is an eco-friendly method., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Environmental monitoring of mercury (Hg 2+ ) ions has become increasingly important as a result of their detrimental effects on biological organisms at all levels. To recognize toxic metal ions, utmost effort has been devoted to developing new materials that are highly selective, ultra-sensitive, and provide rapid response. In this context, a new chemosensor, 2-imino [N - (N-amido phenyl)]-6-methoxy-3-carbethoxy quinoline (L), has been synthesized by combining 2-formyl-6-methoxy-3-carbethoxy quinoline and benzhydrazide and it has been extensively characterized by NMR, FTIR, ESI-Mass and SCXRD analysis. Probe L has excellent specificity and sensitivity toward Hg 2+ ions in semi-aqueous solutions, with a detection limit of 0.185 μM, regardless of the presence of other interfering cations. Chromogenic behavior was demonstrated by the L when it changed the color of the solution from colorless to light yellow, a change that can be observed visually. The probe L forms a 1:1 stochiometric complex with an estimated association constant (K a ) of 6.74 × 10 4  M -1 . The 1 H NMR change and density functional theory calculations were analyzed to improve our understanding of the sensing mechanism. Also, an inexpensive and simple paper-based test kit has been developed for the on-site detection of mercury ions in water samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In recent years, hemi-cyanine dyes have been widely used as biological probes due to their red-light emission characteristics and high fluorescence quantum yield. In this study, we synthesized a novel hemi-cyanine dye containing a tetrahydropyridine ring. A lysosomal target was introduced into its structure to create a new pH-sensitive near-infrared fluorescent probe that successfully targeted lysosomes. The results showed that when the probe solution was excited at the absorption wavelength of 650 nm, its fluorescence emission wavelength was about 700 nm, and the peak intensity changed with different pH values in a wide range. Therefore, this probe enabled non-invasive detection of changes in the acidic environment of lysosomes in living organisms and showed good imaging capabilities. Moreover, the probe displays high sensitivity and good stability. The theoretical calculation of a probe structure has also been completed to discuss the relationship between structure and property., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A novel multimode colorimetric and fluorescent chemosensor was developed using an 8-hydroxy quinoline carbaldehyde Schiff base with a quinoline hydrazide probe (E)-2-((2-(quinolin-2-yl)hydrazineylidene)methyl)quinolin-8-ol (L). NMR ( 1 H & 13 C), FTIR, and HR-mass spectral characterization techniques confirmed the probe L structural conformation. As Probe L contacts Pb 2+ ions, a color change and turn-off emission can be visually detected in EtOH:H 2 O (1:1, v/v, pH = 7.21) medium. The probe displays a good emission at 440 nm due to the combined ESIPT and ICT process. The Pb 2+ ion interacts with the probe and selectively quenches fluorescence by inhibiting ESIPT and >CN- isomerization. As per Job's plot, L-Pb 2+ complex formation occurred in a 1:1 stoichiometric ratio, with association constant (K a ) and quenching constant (K sv ) estimated at 1.52 × 10 5  M -1 and 4.12 × 10 5  M, respectively. The detection limits of Pb 2+ by spectrophotometric and spectrofluorometric were 1.99 μM (41 ppb) and 23.4 nM (485 ppt), respectively. Additionally, the test paper kit and RGB tool were used to monitor the color changes of L with Pb 2+ and the LOD was found to be 5.99 μM (125 ppb). Its recognition mechanism has been verified by 1 H NMR, ESI-mass, and theoretical studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Recently, the aim of analytical community is to reduce the usage of hazardous chemicals; so eco-friendly, rapid, selective and cost-effective methods were developed for simultaneous determination of montelukast sodium (MKT) and loratadine (LRT). The first method was based on chromatographic separation performed on precoated silica gel 60 GF254 plates with ethyl acetate-ethanol 9: 1 (v/v) as the mobile phase. The developed plates were scanned and quantified at 260 nm. The method gives linear correlation over concentration ranges of 0.3-3.6 μg/spot and 0.2-4.0 μg/spot for MKT and LRT, respectively. It was also successfully applied to analysis of both drugs in their pharmaceutical preparation and human plasma. The other methods are UV-spectrophotometric methods based on smart spectra manipulating to zero order spectrum of each drug. These methods are named response correlation (RC), a-centering and ratio derivative methods. RC and a-centering methods were dependent on the presence of an isosbestic point between the overlapped spectra of both drugs. While ratio derivative method based on manipulation of the ratio spectra of both drugs. The two drugs obey Beer-Lambert law over the concentration ranges of 3.0-30.0 μg/mL in the three spectrophotometric methods. Moreover, the greenness of the developed methods is assessed using suitable analytical Eco-Scale and Green Analytical Procedure Index., (Published by Oxford University Press 2023.)

The global production of textiles utilizes numerous large-volume chemicals that may remain to some extent in the finished garments. Arylamines, quinolines, and halogenated nitrobenzene compounds are possible mutagens, carcinogens and/or skin sensitizers. For prevention, control of clothing and other textiles must be improved, especially those imported from countries without regulations of textile chemicals. An automated analytical methodology with on-line extraction, separation, and detection would largely simplify screening surveys of hazardous chemicals in textiles. Automated thermal desorption-gas chromatography/mass spectrometry (ATD-GC/MS) was developed and evaluated as a solvent-free, direct chemical analysis for screening of textiles. It requires a minimum of sample handling with a total run time of 38 min including sample desorption, chromatographic separation, and mass spectrometric detection. For most of the studied compounds, method quantification limit (MQL) was below 5 µg/g for 5 mg of textile sample, which is sufficiently low for screening and control of quinoline and arylamines regulated by EU. Several chemicals were detected and quantified when the ATD-GC/MS method was applied in a limited pilot screening of synthetic fiber garments. A number of arylamines were detected, where some of the halogenated dinitroanilines were found in concentrations up to 300 µg/g. This is ten times higher than the concentration limit for similar arylamines listed by the EU REACH regulation. Other chemicals detected in the investigated textiles were several quinolines, benzothiazole, naphthalene, and 3,5-dinitrobromobenzene. Based on the present results, we suggest ATD-GC/MS as a screening method for the control of harmful chemicals in clothing garments and other textiles., (© 2023. The Author(s).)

Mitochondria are the sites of respiration in cells, and they participate in many indispensable biological processes. Because variations in mitochondrial viscosity can lead to dysfunctions of mitochondrial structure and function (and even induce malignant diseases), new sensors that can accurately monitor changes in mitochondrial viscosity are essential. To better investigate these changes, we report the development and evaluation of a novel benzothiophene-quinoline-based fluorescent chemosensor (BQL) that was designed especially for monitoring mitochondrial viscosity. BQL demonstrated a large Stokes shift (minimizing interference from autofluorescence) and a good response to viscosity (using the TICT principle). Moreover, BQL demonstrated little to no pH-dependency, polarity-dependency, or interference from other analytes. Thus, BQL has an excellent specificity for viscosity. BQL was used to monitor viscosity changes in mitochondria induced by ion carriers, and was used to report on viscosity in real time during mitophagy. To sum up, BQL provided a new approach for detecting viscosity in living cells and in vivo. BQL should prove to be an excellent tool for the analysis of viscosity changes in live cells., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Wastewater containing quinoline has become a common pollutant in water and soil environments, which poses a threat to human health due to its carcinogenicity, teratogenicity, and mutagenicity. Quinoline's stability and toxicity hinders its degradation by conventional physicochemical and biological methods. In this contribution, Fe-Co-Bi/kaolin particle electrodes were prepared for the efficient degradation of quinoline in wastewater, and characterized by using scanning electron microscope, X-ray diffraction, pyridine-IR, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, and four-probe resistivity test. Parameters affecting the degradation efficiency were optimized to be the particle electrode dosage of 40 g/L, pH 3.5, H 2 O 2 addition of 67.6 mmol/L, electrical conductivity of 12.7 ms/cm, and voltage of 20 V. The constructed three-dimensional catalytic particle electrode system (3D-CPE) achieved 92.1% removal rate of chemical oxygen demand (COD) under the optimal conditions. Hydroxyl radicals (•OH) generated in the 3D-CPE process were identified by radical scavenging tests and electron spin response analysis. To unravel the degradation mechanism, the intermediate products were identified by using high performance liquid chromatography-mass spectrometry. The degradation mechanism was discussed with the help of theoretical calculation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The global manufacturing of clothing is usually composed of multistep processes, which include a large number of chemicals. However, there is generally no information regarding the chemical content remaining in the finished clothes. Clothes in close and prolonged skin contact may thus be a significant source of daily human exposure to hazardous compounds depending on their ability to migrate from the textiles and be absorbed by the skin. In the present study, twenty-four imported garments on the Swedish market were investigated with respect to their content of organic compounds, using a screening workflow. Reversed-phase liquid chromatography coupled to electrospray ionization/high-resolution mass spectrometry was used for both suspect and non-target screening. The most frequently detected compound was benzothiazole followed by quinoline. Nitroanilines with suspected mutagenic and possible skin sensitization properties, and quinoline, a carcinogenic compound, were among the compounds occurring at the highest concentrations. In some garments, the level of quinoline was estimated to be close to or higher than 50,000 ng/g, the limit set by the REACH regulation. Other detected compounds were acridine, benzotriazoles, benzothiazoles, phthalates, nitrophenols, and organophosphates. Several of the identified compounds have logP and molecular weight values enabling skin uptake. This pilot study indicates which chemicals and compound classes should be prioritized for future quantitative surveys and control of the chemical content in clothing as well as research on skin transfer, skin absorption, and systemic exposure. The results also show that the current control and prevention from chemicals in imported garments on the Swedish market is insufficient., (© 2021. The Author(s).)

Meat and meat products are indispensable part of our diet. Heat processing of these tasty foods such as fried fish causes to form heterocyclic aromatic amines (HAAs). The sources of heating have directly affected on the level and type of HAAs. In this research, 2-amino-1-methyl-6-phenylimidazo [4'5-b] pyridine (PhIP), 2-amino-3-methylimidazo [4,5-f]quinolone (IQ), 2-amino-3,4-dimethylimidazo [4,5-f] quinoline (MeIQ) and 2-amino-3,4-dimethylimidazo [4,5-f] quinoxaline (MeIQx) were determined using an efficient analytical methodology coupled with high-performance liquid chromatography. The effective parameters were optimized by central composite design. The results of this survey demonstrated that rang of relative standard deviation were between 4.5 and 8.2, extraction recoveries were obtained 86-97% and limits of detection were between 0.40 and 0.63 for 4 HAAs. The amounts of HAAs found in 20 different fried fish samples were between 0 and 4.8 ng g-1. PhIP with 1.57 ng g-1 and MeIQ with 2.08 ng g-1 have the lowest and highest average level of HAAs, respectively., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The current study developed a cheap and effective method for the simultaneous extraction of 14 heterocyclic aromatic amines (HAAs) in food matrix. Core-shell Fe 3 O 4 @PDA nanoparticles were constructed and acted as the magnetic solid-phase extraction adsorbent to separate and purify HAAs from meat products for the first time. Then, UPLC-MS/MS technique was employed to identify and quantify the HAAs easily. Fe 3 O 4 @PDA nanoparticles were synthesized and characterized successfully. Totally 14 HAAs were completely separated in 19.99 min with good regression coefficients. LODs and LOQs were in the range of 0.013-0.247 ng/g and 0.056-0.803 ng/g, respectively. The intra-day precisions and inter-day precisions were below 9%. Except for IQ[4,5-b], Phe-p-1, PhIP, other 11 types of HAAs (DMIP, 1,5,6-TMIP, IQ, IQx, MeIQ, MeIQx, 7,8-DiMeIQx, AαC, MeAαC, Harman, Norharman) could acquire relatively high recoveries (71.06%-108.49%). The proposed method was successfully devoted to the evaluation of HAAs levels in 8 commercial meat products to verify the adaptability., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Cryptococcus neoformans is a pathogenic fungus which causes millions of deaths and infections, especially threatening immunocompromised individuals. During the development of new drugs, the ubiquitination has been found to play an important role in the regulation of the virulence and cell cycle of this fungus. Based on this mechanism, ubiquitination-related mutant strains exhibiting cell cycle arrest have been established for drug development for the fungus. However, flow cytometry detection of the cell cycle in fungi is generally difficult because the thick cell wall and capsule of fungi generally contribute to a nonspecific signal of cytometry. In this study, an improved method, derived from Saccharomyces cerevisiae assays, is developed to specifically stain C. neoformans , in whose cell cycle the G1 and G2 peaks are separated enough to be allowed for cell cycle analysis. As a result, the improved method facilitates the detection of the alterations in the cell cycle of C. neoformans with a mutation that results in cell cycle arrest, which distinctly delays the cell division of C. neoformans . Thus, the improved method reported here provides detailed technical information regarding assays on C. neoformans and, more importantly, offers a solution for assessing the cell cycle in other fungi in the future. Abbreviation : PI: propidium iodide.

Rationale: Brain metastases are a common complication in patients with non-small-cell lung cancer (NSCLC). Anlotinib hydrochloride is a novel multi-target tyrosine kinase inhibitor (TKI) exhibiting a superior overall response rate for brain metastases from NSCLC. The penetrability of anlotinib and three generations of epidermal growth factor receptor (EGFR) TKIs (osimertinib, afatinib and gefitinib) into brain microvascular endothelial cells (HBMECs) was compared., Methods: A sensitive quantification method for the four TKIs was developed using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). Anlotinib and the three EGFR TKIs were separated on an ACQUITY BEH C18 column after a direct protein precipitation, and then analyzed using electrospray ionization in positive ion mode. The linearity, accuracy, precision, limit of quantification, specificity and stability were assessed., Results: The four analytes could be efficiently quantified in a single run of 3.8 min. The validation parameters of all analytes satisfy the acceptance criteria of bioanalytical method guidelines. The calibration range was 0.2-200 ng mL -1 for anlotinib and gefitinib, 1-500 ng mL -1 for osimertinib and 1-200 ng mL -1 for afatinib. The penetration of anlotinib across HBMECs was comparable with that of afatinib and gefitinib but less than that of osimertinib., Conclusions: A sensitive LC/MS/MS method to simultaneously measure anlotinib, osimertinib, afatinib and gefitinib in cell extracts was successfully validated and applied to determine their uptake inside HBMECs, which could pave the way for future research on the role of anlotinib in NSCLC brain metastases., (© 2020 John Wiley & Sons, Ltd.)

Fexofenadine hydrochloride is an antihistamine agent used for the treatment of allergic disorders like rhinitis. It is a second generation antihistamine. Montelukast sodium is an anti-asthmatic agent and leukotriene receptor antagonist used in the treatment of respiratory disorders. This article exemplifies the reported analytical methods like electrometric methods, ultraviolet spectroscopy, mass spectroscopy, thin layer chromatography, high performance liquid chromatography, high performance thin layer chromatography and tandem spectroscopy for determination of fexofenadine HCl and montelukast sodium in dosage form and in biological matrices. This review covers almost all the analytical methods for fexofenadine hydrochloride and montelukast sodium form 1968-2018 years. Complete analytical validation parameters reported are discussed in this review for both analytes. Among various analytical methods, HPLC and UV-visible spectrophotometry were found to be the most extensively used methods by the researchers.

We report the formation and characterization of two diastereomeric thiol-ene addition products of the asthma medication Montelukast within chewing tablets. Widespread tin-based thermal stabilizers dioctyltin bis(2-ethylhexyl thioglycolate) and monooctyltin tris(2-ethylhexyl thioglycolate), used in the manufacturing process of the medication's forming foil, were identified as the source of the thiol reactant, showing that these stabilizers may play a part in the degradation of Montelukast and APIs with functionalities similar to those of Montelukast, which should be considered during development of medication. The isolation and analysis of these impurities was performed by HPLC and UV-vis spectroscopy. HRMS and NMR data were collected to characterize and determine the structures of these compounds.

The signal orchestration between legumes and the rhizobia attribute to symbiotic nitrogen fixation through nodule formation. Root nodules serve as a nutrient-rich reservoir and harbor diverse microbial communities. However, the existence of non-rhizobial endophytes (NRE) and their role inside the root nodules are being explored; there is no evidence on yeast microflora inhabiting nodule niche. This study focused on unraveling the presence of yeast in the root nodules and their possible function in either nodulation or signal exchange. From the root nodules of blackgram, two yeast strains were isolated and identified as Candida glabrata VYP1 and Candida tropicalis VYW1 based on 18S rRNA gene sequencing and phylogeny. These strains possessed plant growth-promoting traits viz., IAA, ACC deaminase, siderophore, ammonia, and polyamine production. The functional capacity of endophytic yeast strains, and their interaction with Rhizobium sp. was further unveiled via profiling volatile organic compounds (VOC). Among the VOCs, α-glucopyranoside and pyrroloquinoline pitches a pivotal role in activating lectin pathways and phosphorous metabolism. Further, lectin pathways are crucial for nodulating bacterium, and our study showed that these endophytic yeasts assist nodulation by Rhizobium sp. via activating the nod factors. The plant growth-promoting traits of NRE yeast strains coupled with their metabolite production, could recruit them as potential drivers in the plant-microbe interaction.

Reactions involving reactive carbonyls, creatinine, and ammonia-producing compounds were investigated in order to clarify the formation of the heterocyclic aromatic amine (HAA) 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ). Obtained results showed that MeIQ was only produced when 2-butenal (crotonaldehyde) was present. Reaction yields depended on the pH, with a maximum around pH 6.5, and on concentrations of crotonaldehyde and creatinine. Ammonia was also required for MeIQ formation, but ammonia was produced by creatinine decomposition. The amount of MeIQ formed increased with reaction time, temperature, and oxygen content in the reaction atmosphere. Activation energy for MeIQ formation from crotonaldehyde, creatinine, and glutamine was 72.2 ± 0.4 kJ·mol -1 . A reaction pathway that explains MeIQ formation is proposed. Obtained results suggest a main role of reactive carbonyls formed in foods (the food carbonylome) on HAA formation. In addition, they provide scientific basis for the understanding of how HAAs are formed and could be mitigated., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Interspecies bacterial competition may occur via cell-associated or secreted determinants and is key to successful niche colonization. We previously evolved Pseudomonas aeruginosa in the presence of Staphylococcus aureus and identified mutations in the Wsp surface-sensing signalling system. Surprisingly, a ΔwspF mutant, characterized by increased c-di-GMP levels and biofilm formation capacity, showed potent killing activity towards S. aureus in its culture supernatant. Here, we used an unbiased metabolomic analysis of culture supernatants to identify rhamnolipids, alkyl quinoline N-oxides and two siderophores as members of four chemical clusters, which were more abundant in the ΔwspF mutant supernatants. Killing activities were quorum-sensing controlled but independent of c-di-GMP levels. Based on the metabolomic analysis, we formulated a synthetic cocktail of four compounds, showing broad-spectrum anti-bacterial killing, including both Gram-positive and Gram-negative bacteria. The combination of quorum-sensing-controlled killing and Wsp-system mediated biofilm formation endows P. aeruginosa with capacities essential for niche establishment and host colonization., (© 2020 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.)

Rice is one of the most important foods in the world due to its high nutritional value and production. Quinclorac, a selective herbicide, is one of the most detected pesticide residues in rice crops according to pesticide monitoring studies. Common methods for the determination of quinclorac in rice are very time-consuming and labour-intensive, so it is important to develop alternative sensitive and simple analytical methods able to detect quinclorac in food samples. Here we propose a fluorometric method for the screening of this herbicide at excitation/emission wavelengths of 238/358 nm/nm, respectively. A modified QuEChERS method was selected for sample treatment due to its simplicity and high recovery yields. The proposed method presents a detection limit of 2.5 ng mL -1 and satisfactory precision. Recovery experiments were performed in different kinds of rice (white and brown) at or below the Maximum Residue Limit established in European Union (5 mg kg -1 ), obtaining values close to 100%. All these characteristics ensure that the proposed method fulfils the requirements for its application in food control.

An HPLC method was developed and validated to quantify and identify several statins (atorvastatin, fluvastatin, pitavastatin and pravastatin) that were used during transdermal drug delivery. The method proved to be most effective with a Restek Ultra C 18 , 250 x 4.6 mm, 5 μm column, a flow rate of 1.0 ml/min, UV detection at 240 nm and injection volume of 10 μl. The mobile phase used was acetonitrile/Milli-Q ® water with 0.1% orthophosphoric acid starting with 30% acetonitrile, which increased linearly to 70% (after 4 min) for up to 10 min and then re-equilibrated to start conditions. This HPLC method indicated linearity (correlation coefficient (R²) of 1) within the concentration range of 0.05-200.00 μg/ml and had an average recovery of 98-103%. Limit of detection (LOD) and limit of quantification (LOQ) showed that statins could still be identified at concentrations of 0.004-0.006 μg/ml with the exception of atorvastatin (quantifiable at 0.013-0.035 μg/ml). Specificity performed during method validation, confirmed that the method was suitable for accurate detection and quantification of the statins when included in the transdermal formulations with other excipients.

Quinoline Yellow (QY, Colour Index No. 47005) is internationally used as a colour additive in foods, drugs, and cosmetics. The manufacture of QY requires sulphonating quinophthalone, and depending on the degree of sulphonation, various forms of QY result, containing different proportions of quinophthalone mono-, di-, and trisulfonic acid sodium salts (monoSA, diSA, and triSA, respectively). Regulations on the specific composition and uses of QY differ across countries with associated differences in names for QY. The QY form certified for use in the U.S. in drugs and cosmetics is known as D&C Yellow No. 10 (Y10). The Code of Federal Regulations (CFR) specifies that Y10 and its lakes consist of predominantly monoSA's, the sum of whose levels is ≥ 75%, and that the sum level of diSA's is ≤ 15%, with one of them (6'8'diSA) at ≤ 3%. The present work reports the development of an HPLC method for determining those CFR-specified values and the level of a non-CFR-specified component, 6'8'5triSA. The selected analytes, 6'SA, 6'5diSA, 6'8'diSA, and 6'8'5triSA, were quantified by using five-point-calibration curves (R 2  > 0.999) with data-point ranges of 9.96-96.53%, 0.54-21.69%, 0.10-5.00%, and 0.11-5.53% by weight, respectively. The method was found to be precise (relative standard deviation values, 0.55-0.80%) and accurate (recovery values, 91.07-99.45%). LOD and LOQ values, respectively, were as follows: 1.23 and 3.70%, 6'SA; 0.42 and 1.26%, 6'5diSA; 0.11 and 0.34%, 6'8'diSA; and 0.01 and 0.04%, 6'8'5triSA. The HPLC method was applied successfully to the analysis of 20 Y10 and eight Y10 lake samples. It can be extended to other QY forms such as E104 and Yellow 203 because it enables analysis of 6'8'5triSA. This paper also addresses the implications of the varying structure depictions and CAS numbers of the QY components that are due to the existence of three tautomeric forms of quinophthalone.

Quinclorac (QNC) is an effective but environmentally persistent herbicide commonly used in rice production. However, few studies have investigated its environmental behavior and degradation. In the present study, we carried out microbial cultures in the presence of QNC to observe changes in soil microbiota and to identify species capable of QNC degradation by using high-throughput sequencing of the 16S rRNA. Pseudomonas was the dominant genus, and Pseudomonas putida II-2 and other species were found to be capable of mineralizing QNC as a source of carbon and energy. However, this degradation rate was slow, only reaching 51.5 ± 1.6% for 7 days at 30 °C on QNC + minimal salt medium. Achromobacter sp. QC36 co-metabolized QNC when rice straw was added into the mineral salt medium containing QNC, and a mixed culture of both strains could mineralize approximately 92% of the 50 mg/L QNC after 5 days of cultivation in the presence of rice straw, at 25-35 °C and pH 6.0-8.0. Non-phytotoxicity of tobacco after degradation of QNC by mixed strains was evidenced in a pot experiment. These results suggest that this mixed culture may be useful in QNC bioremediation and can be used as a bio-formulation for agro-economical and industrial application., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Two selective and sensitive chromatographic methods were developed for simultaneous determination of new combination of quinfamide and mebendazole in bulk powder and in pharmaceutical formulation. The first method is HPTLC by which separation was obtained using silica gel HPTLC F254 plates and a simple mobile phase consisting of methanol:toluene (2:6, v/v) and the separated bands were scanned at 254 nm. The second method RP-HPLC that comprised isocratic separation of both drugs on a Phenomenex C18 column using a green mobile phase consisting of double distilled water:methanol (30:70, v/v) at a flow rate of 0.8 mL/min and UV detection at 254 nm. The developed methods were validated and proved to meet ICH guidelines. Successful application of the developed methods was carried out for determination of quinfamide and mebendazole in Vermox Plus® tablets. Statistical comparison between the developed chromatographic methods and the reported simultaneous equation spectrophotometric method showed that there was no significant difference between them, proving the ability of applying the proposed methods in quality control testing of the studied drugs. The developed methods are considered the first chromatographic methods for simultaneous determination of quinfamide and mebendazole; moreover, they offered sensitive and selective eco-friendly methods for analysis of the studied drugs., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Although anaerobic membrane bioreactor (AnMBR) has been proposed for the treatment of phenolic wastewater, the membrane fouling is still a major obstacle. The effects of dosing of granular activated carbon (GAC) and polyaluminum chloride (PACl) on the treatment performance and membrane fouling of anaerobic ceramic membrane bioreactor were investigated for treating phenol- and quinoline-containing wastewater. The results suggested that the one-off dosing of GAC resulted in a decrease of protein/carbohydrate ratio, which might account for the aggravation of membrane fouling alongside with the decreased flocs size. Nevertheless, the substrate uptake rates (SUR) of phenol and quinoline, and the specific methanogenic activity of sludge at the GAC dosing stage of experimental reactor (R1) were 8.79 ± 0.63 mg phenol g -1 MLVSS d -1 , 7.01 ± 0.09 mg quinoline g -1 MLVSS d -1 and 0.27 ± 0.01 g COD CH4 g -1 MLVSS d -1 , which were 1.69, 3.59 and 1.93 times higher than that of the control reactor (R2). The dosing of PACl reduced the membrane fouling rate by changing the floc structure of sludge, as well as the component of SMP and EPS. However, the substrate uptake rate of quinoline was declined. This work provides a comprehensive evaluation on the effect of GAC and PACl dosing on membrane fouling and performance of anaerobic ceramic membrane bioreactor treating phenol-and quinoline-containing wastewater.

Dihydroartemisinin (DHA) and piperaquine (PPQ) are two drugs used in an artemisinin-based combination therapy (ACT). The circulation of counterfeit antimalarial drugs demands the development of simple, point-of-care (POC) tests for monitoring drug quality. Here we aimed to design an antibody-based lateral flow dipstick assay for simultaneous quality control of DHA and PPQ. To obtain a monoclonal antibody (mAb) for PPQ, one structural unit of the symmetric PPQ molecule was used to derive a carboxylic acid for linkage to a carrier protein as immunogen. Screening of hybridoma cells identified an mAb 4D112B2 that reacted with the PPQ-based immunogen. A highly-sensitive icELISA was designed based on this mAb, which showed 50% inhibition concentration of PPQ at 1.66 ng/mL and a working range of 0.35 - 7.40 ng/mL. The mAb showed 10.2, 15.9 and 30.4% cross reactivity to hydroxychloroquine sulfate, chloroquine and amodiaquine, respectively. No cross reactivity was observed to lumefantrine, mefloquine artemisinin and its derivatives. Using our previous DHA dipstick design, a lateral flow dipstick for simultaneous analysis of PPQ and DHA was developed. The indicator ranges for PPQ and DHA were 2 - 5 μg/mL and 250 - 500 ng/mL, respectively. The dipstick was used to semi-quantitatively analyze PPQ and DHA content in commercial ACT drugs, which produced agreeable results to those determined by high-performance liquid chromatography. This combination dipstick makes it a potential POC device for quality control of the two active ingredients in a commonly used ACT., (© 2019 John Wiley & Sons, Ltd.)

Shorter DNA probes provide better specificity for hybridization, but they may not form stable duplexes at room temperature. In this study, we used thiazole orange to follow DNA hybridization upon freezing and achieved stable 5-mer duplex DNA. Using multiple short probes in tandem, long DNA could also be studied. This study provides insights into DNA hybridization in the frozen state and expands the application of freezing for nucleic acid chemistry.

In this study, CuFe 2 O 4 nanocomposite loaded on natural sepiolite (CuFe 2 O 4 /SEP) was prepared by the citrate sol-gel method. CuFe 2 O 4 /SEP was characterized by X-ray diffraction, Brunauer-Emmett-Teller adsorption analysis, scanning electron microscopy, and energy dispersive spectroscopy. The CuFe 2 O 4 /SEP composite was stable and showed an excellent catalytic activity for ozonation. The efficiency of quinoline mineralization in the catalytic ozonation with CuFe 2 O 4 /SEP was 90.3%, and this value was 5.4 times higher than that of the uncatalyzed ozonation (16.8%). The quinoline mineralization followed a pseudo first-order kinetics with all the catalysts. The rate constant for the mineralization of quinoline by ozonation in the presence of CuFe 2 O 4 /SEP was 0.0885 min -1 , which was 16.7 times higher than that in ozone alone (0.0053 min -1 ). Radical scavenging tests revealed that hydroxyl radical (OH) and superoxide radical (O 2 - ) were the reactive oxygen species (ROS) in the quinoline degradation. In the presence of CuFe 2 O 4 /SEP, ozone and hydrogen peroxide were rapidly converted into the ROS. Although neutral and alkaline pH were more beneficial for the quinoline mineralization, CuFe 2 O 4 /SEP exhibited significant catalytic activity even under acidic conditions. Meanwhile, five-cycle successive tests suggested that CuFe 2 O 4 /SEP was recyclable and hence, stable. Furthermore, the feasibility of the catalytic ozonation for the treatment of biologically treated coking wastewater was evaluated. The catalytic ozonation resulted in 57.81% total organic carbon removal efficiency at 60 min, which was 2.9 times higher than that in the uncatalyzed ozonation (19.99%)., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Synthetic colorants are largely used in the pharmaceutical products to increase the attractiveness of products and to help patients distinguish between pharmaceuticals. Despite their commercial advantages, synthetic colorants may, in some cases, have a negative impact on the human body. It is therefore imperative to measure the quantities in food products and pharmaceuticals with a fast, reliable, and sensitive method. Objective: The analyzed synthetic colorants in this study are Erythrosine [(E) E127], Quinoline Yellow [(QY) E104], and Indigo Carmine [(IC) E132]. The aim of this study was to develop and validate a new method for the preconcentration and simultaneous determination of these colorants in pharmaceutical preparations. Method: The developed method has many advantages such as novelty, sensitivity, cost effectiveness, speed, and environmental friendliness. This method is based on the cloud-point extraction (CPE) method coupled with first-derivative spectrophotometry (FDS). In the proposed method, QY, E, and IC were extracted from an aqueous solution by using mixed micelles of TritonX-100 and cetyltrimethylammonium bromide. The effect of the main parameters such as solution pH, surfactant and salt concentration, incubation time, and temperature on the CPE of colorants were investigated and optimized. Under the optimal conditions, the extracted surfactant-rich phase was diluted with acetone, and the first-derivative absorbance values were measured at wavelengths 408, 497, and 637 nm for QY, E, and IC, respectively. The CPE-FDS method was applied in the range of 1.0-6.0 μg/mL for E and QY, and 0.3-1.8 μg/mL for IC. Results: The results showed higher correlation coefficients of 0.9990-0.9993 for each colorant. Furthermore, the method was validated for precision and accuracy and assessed the colorants' contents in the synthetic mixtures that contained different ratios of colorants and pharmaceutical samples. The LOD and LOQ values were 31.0 and 103.0 ng/mL for E, 57.0 and 190.0 ng/mL for QY, and 48.0 and 160.0 ng/mL for IC, respectively. The RSDs at the intermediate concentration level (1.2 μg/mL for IC and 3 μg/mL for QY and for E) were <5%. The recovery values in different ratios of colorants were in the ranges of 90.42-101.14, 92.40-105.54, and 96.15-101.25% for E, IC, and QY, respectively. CPE-FDS was also successfully applied to the simultaneous analysis of the QY, IC, and E contents in the various pharmaceutical samples. The obtained results were statistically compared with those obtained by the green HPLC method that was previously reported by Yoshioka et al. and modified by us in this study. Conclusions: The data observed indicated that the CPE-FDS method does not require use of great samples for determination of trace amounts of E, IC, and QY and allows for the determination of analytes in high matrix effect samples such as suspension and syrup. The study concludes that the proposed CPE-FDS method could be considered an alternative to the existing chromatographical methods for the simultaneous determination of trace amounts of E, IC, and QY in pharmaceutical dosage forms for routine analysis. Highlights: A new and effective procedure, simultaneous determination, trace amounts of E, QY, and IC was developed. This is the first report that uses CPE coupled with FDS for the analysis of E, QY, and IC. CPE avoids the use of costly, hazardous, and flammable solvents in large quantities. FDS resolves two or three overlapping spectra and eliminates matrix interferences. CPE-FDS did not require use of large samples for determination of trace colorants.

Activated carbon made from agricultural waste (walnut shells) was investigated as a suitable adsorbent for effectively removing quinoline from industrial wastewater. The activated carbon was treated with phosphoric acid and oxidized by ammonium persulfate and its ability to adsorb pyridine and quinoline in aqueous solution was investigated. Kinetic parameters for the adsorption process were determined through pseudo-first-order and pseudo-second-order kinetic models and intraparticle diffusion models. Equilibrium experiments and adsorption isotherms were analyzed using Langmuir and Freundlich adsorption isotherms. After reaching equilibrium, the activated carbon adsorbed quinoline in preference to pyridine: the equilibrium adsorptions from individual aqueous solutions (200 μL L -1 ) of quinoline and pyridine were 166.907 mg g -1 and 72.165 mg g -1 , respectively. Thermodynamic studies of quinoline adsorption were conducted at different temperatures and indicated that quinoline adsorption was an endothermic and spontaneous process. The column-adsorption of quinoline and pyridine was consistent with the Thomas model and the Yoon-Nelson model. The removal efficiency of quinoline reached more than 97% for a velocity of 6 mL min -1 at the initial adsorption stage.

Fluorescence quenching behavior of artificial food colorant quinoline yellow (QY), on interaction with l-cysteine stabilized copper nanoclusters (l-Cys-CuNCs) is investigated in this work. For this purpose, l-cysteine stabilized CuNCs were synthesized and characterized using various analytical techniques. Results demonstrated that the synthesized probe (size ~2 nm) had very promising optical features such as bright blue fluorescence, significant quantum yield and excellent photostability. l-Cys-CuNCs can function as a fluorescence sensor by selectively sensing QY among other yellow colorants, giving a detection limit as low as 0.11 μM. The developed sensor exhibited a linear concentration range from 5.50 to 0.20 μM. The developed fluorescence assay was successfully applied for testing commercial samples, thereby making this sensing strategy significant for quality control of food stuffs., (© 2019 John Wiley & Sons, Ltd.)

Introduction: Breast implants are associated with complications such as capsular contracture, implant rupture and leakage often necessitating further corrective surgery. Re-operation rates have been reported to occur in up to 15.4% of primary augmentation patients and up to 27% in primary reconstructions patients within the first three years (Cunningham, 2007). The aim of this study was to examine the mechanical and surface chemical properties as well as the fibroblast response of retrieved breast implants in our unit to determine the in vivo changes which occur over time., Methods: Ethical approval was obtained. 47 implants were retrieved. Implantation time ranged from 1 month to 388 months (Mean 106.1 months). Tensile strength, elongation, Young's modulus and tear strength properties were measured using Instron 5565 tensiometer on anterior and posterior aspects of the implant. Attenuated total reflectance-fourier transform infra-red spectroscopy (ATR-FTIR), wettability and scanning electron microscopy (SEM) analysis was performed on the shell surfaces. Bicinchoninic acid assay was performed to determine shell protein content. The fibroblast response was determined by seeding HDFa cells on the retrieved implants and cell metabolism measured using Alamar Blue™ assay., Results: Mechanical properties fall with increasing duration of implantation. There were no significant changes in ATR-FTIR spectra between ruptured and intact implants nor significant changes in wettability in implants grouped into 5 year categories. SEM imaging reveals surface degradation changes with increasing duration of implantation., Conclusions: With increasing duration of implantation, mechanical properties of the breast implants fall. However this was not associated with surface chemical changes as determined by ATR-FTIR and wettability nor protein content of the shells. Thus the reduction in mechanical properties is associated with breast implant failure but further research is required to elucidate the mechanisms., (Copyright © 2018. Published by Elsevier Ltd.)

Stable isotope labeled (SIL) compounds have been commonly used as internal standards (IS) to ensure the accuracy and quality of liquid chromatography-mass spectrometry (LC-MS) bioanalytical assays. Recently, the application of SIL drugs and LC-MS assays to microdose absolute bioavailability (BA) studies has gained increasing attention. This approach can provide significant cost and time saving, and higher data quality compared to the accelerator mass spectrometry (AMS)-based method, since it avoids the use of radioactive drug, high-cost AMS instrumentation and complex measurement processes. It also eliminates potential metabolite interference with AMS-based assay. However, one major challenge in the application of this approach is the potential interference between the unlabeled drug, the microdose SIL drug, and the SIL-IS during LC-MS analysis. Here we report a convenient and cost-effective strategy to overcome the interference by monitoring the isotopic ion (instead of the commonly used monoisotopic ion) of the interfered compound in MS analysis. For the BMS-986205 absolute BA case study presented, significant interference was observed from the microdose IV drug [ 13 C 7, 15 N]-BMS-986205 to its SIL-IS, [ 13 C 7, 15 N, D 3 ]-BMS-986205, since the difference of nominal molecular mass between the two compounds is only 3 mu, and there is a Cl atom in the molecules. By applying this strategy (monitoring the 37 Cl ion for the analysis of the IS), a 90-fold reduction of interference was achieved, which allowed the use of a synthetically accessible SIL compound and enabled the fast progress of the absolute BA study. This strategy minimizes the number of stable isotope labels used for avoiding interference, which greatly reduces the difficulty in synthesizing the SIL compounds and generates significant time and cost savings. In addition, this strategy can also be used to reduce the MS response of the analyte, therefore, avoiding the detector saturation issue of LC-MS/MS assay for high concentration BMS-986205. A LC-MS/MS assay utilizing this strategy was successfully developed for the simultaneous analysis of BMS-986205 and [ 13 C 7 , 15 N]-BMS-986205 in dog plasma using [ 13 C 7, 15 N, D 3 ]-BMS-986205 as the IS. The assay was successfully applied to a microdose absolute BA study of BMS-986205 in dogs. The assay was also validated in human plasma and used to support a human absolute BA study. The same strategy can also be applied to other compounds, including those not containing Cl or other elements with abundant isotopes, or other applications (e.g. selection of internal standard), and the applications were presented., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In 2013, quinoxyfen was included in the list of priority hazard pollutants of the European Water Framework Directive due to its toxicity to aquatic organisms. However, few analytical methods for the analysis of this fungicide have been reported and no rapid immunochemical methods have been published so far. In the present study, immunoreagents for quinoxyfen analysis were generated for the first time and an enzyme-linked immunosorbent assay was developed. Two carboxylated derivatives of quinoxyfen were designed on the basis of the minimum energy conformation of the target compound. Active esters of those novel compounds were prepared using N,N'-disuccinimidyl carbonate, and purified for covalent coupling to proteins. Matrix-assisted laser desorption mass spectrometry of the prepared bioconjugates showed optimum hapten-to-protein molar ratios. Moreover, high-affinity antibodies specific of quinoxyfen were raised. As proof of concept, an immunoassay was evaluated using a heterologous conjugate, which afforded sensitivity values in the low nanomolar range. Moreover, excellent recoveries and coefficients of variation were obtained from the analysis of environmental water samples fortified with quinoxyfen. A limit of quantification of 60 μg/L was determined. The prepared bioconjugates and antibodies could be valuable immunoreagents for the development of a variety of rapid immunosensors for quinoxyfen determination in environmental samples., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Quinclorac is a selective herbicide commonly used in China to control monocotyledonous weeds in paddy fields. A field experiment was conducted to quantify the environmental behavior of quinclorac in acidic paddy soil under rice (Oryza sativa L.) field conditions, and to evaluate the risk of its residues to the subsequent crop of tobacco (Nicotiana tabacum L.). Rice was sprayed once with quinclorac 50% WP at 562.5, 375.0, or 187.5 g a.i. ha -1 at 7 days after transplanting the seedlings. Decay of quinclorac in paddy field soil followed first-order kinetics, with a half-life of 28.29-30.27 days. At harvest time, 0.090, 0.074 and 0.034 mg kg -1 of quinclorac were found in soils following the above-described treatments, respectively. Leaves of the subsequent crop, tobacco, sown the year after the quinclorac treatments, exhibited different dose-dependent degrees of visible phytotoxicity symptoms.

The compounds of N-Methylanhydrotetrahydroberberrubine A, dictamnine and eudesmin were the primary bioactive components in the roots of Zanthoxylum armatum DC (Z. armatum). To clarify the pharmacokinetics and distribution of these three compounds, an ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was employed to determine the contents of these three compounds in rat plasma and seven tissues. The separation was achieved on a Kinetex XB-C18 100A column (2.1 × 50 mm, 2.6 μm, Phenomenex). The optimized mobile phase system was set with 0.1‰ formic acid aqueous solution (A) and acetonitrile (containing 0.1‰ formic acid) (B) with a programmed elution of 0.00 to 0.50 min, 2% B; 0.51-4.00 min, 30%-60% B; and 4.01-5.00 min, 2% B. All analytes were measured with optimized multiple reaction monitoring (MRM) in the positive ion ESI mode. Berberine hydrochloride was selected as the internal standard (IS). The MS/MS transitions of N-Methylanhydrotetrahydroberberrubine A, dictamnine, eudesmin and IS were 339.9135.1, 200.1 → 129.1, 387.4 → 369.0 and 337.1 → 321.1, respectively. The lower limits quantification (LLOQ) of the three analytes was 0.5-20 ng/ml. The linear ranges were 0.5-400 ng/ml for N-Methylanhydrotetrahydroberberrubine A and dictamnine and 20-4000 ng/ml for eudesmin. The present analysis showed that the two alkaloids were quickly absorbed, with T max in 0.167-0.292 h, and eudesmin was absorbed in 2.5 h. Moreover, all compounds were found at high concentrations in the gastrointestinal track. These results are helpful for further investigation of the clinical application of Z. armatum., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Quinclorac, a widely used herbicide in agriculture, has been recognized as an emerging environmental pollutant owing to its long persistence and potential risk to humans. However, no related information is available on the degradation of quinclorac by employing oxidants. Herein, the reactivity of quinclorac with permanganate was systematically investigated in water by combining experimental and computational approaches. The reaction followed overall second-order kinetics pointing to a bimolecular rate-limiting step. The second-order rate constant was found to be 3.47 × 10-3 M-1 s-1 at 25 °C, which was independent of pH over the range from 5 to 9 and was dependent on temperature over the range from 19 to 35 °C. The initial product was identified by UPLC-Q-TOF-MS to be mono-hydroxylated quinclorac, which was more susceptible to further oxidation. The result could be supported by the complete simulation of the reaction process in DFT calculations, indicating the [3 + 2] cycloaddition oxidation of the benzene ring in the rate-limiting step. The plausible mechanism was then proposed, accompanied by the analysis of the HOMO indicating the hydroxylation position and of the ESP suggesting a more electron-rich moiety. Considering the high effectiveness and low toxicity, permanganate oxidation was considered to be a very promising technique for removing quinclorac from aquatic environments.

Quinclorac, a highly selective auxin herbicide, is widely used for controlling weeds in rice field. However, the residual quinclorac is toxic to many crops, vegetables, and aquatic animals, resulting in one of the major problems in crop rotation. Here, we investigated the degradation of quinclorac by strain AH-B, which was isolated from long-term quinclorac-contaminated soil using continuous circulating fluidized bed reactor and subjected to atmospheric and room temperature plasma mutation. Morphological examination, 16S rRNA gene sequencing, and phylogenetic analysis revealed that strain AH-B was Streptomyces sp. The quinclorac degradation efficiency of AH-B in liquid medium was 97.2% after 18 days when the initial quinclorac concentration was 20 mg L -1 . The degradation products were 3-chloro-7-methoxy-8-quinoline-carboxylic, 3-chloro-7-methyl-8-quinoline-carboxylic, 3-chloro-7-oxyethyl-8-quinoline-carboxylic, and 3,7-dichloro-6-methyl-8-quinoline-carboxylic. The inoculum size, initial quinclorac concentration, pH, and temperature were found to affect quinclorac degradation efficiency of AH-B. High-performance liquid chromatography-electrospray ionization tandem mass spectrometry analysis revealed that quinclorac degradation by AH-B produced many products. In soil with initial quinclorac content of 1 mg kg -1 dry soil, addition of AH-B resulted in 87.5% quinclorac degradation after 42 days, while that in the control (without AH-B) was 22.4%. Furthermore, microecological analysis using next-generation sequencing of 16S rRNA geneshowed that some bacterial species, such as Bacterioides and Proteobacteria, could survive in quinclorac-contaminated soil, while some bacteria, such as Firmicutes, were very sensitive to quinclorac. Besides, some fungal species, such as Basidiomycota, could also survive quinclorac-contamination. After 42 days, the diversity of bacteria and fungi in soil treated with AH-B was higher than that in the control, implying that bioaugmentation with strain AH-B could reduce quinclorac toxicity to microorganisms in soil., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

After several decades of widespread use for mapping elemental ions and small molecular fragments in surface science, secondary ion mass spectrometry (SIMS) has emerged as a powerful analytical tool for molecular imaging in biology. Biomolecular SIMS imaging has primarily been used as a qualitative technique; although the distribution of a single analyte can be accurately determined, it is difficult to map the absolute quantity of a compound or even to compare the relative abundance of one molecular species to that of another. We describe a method for quantitative SIMS imaging of small molecules in agar-based microbial communities. The microbes are cultivated on a thin film of agar, dried under nitrogen, and imaged directly with SIMS. By use of optical microscopy, we show that the area of the agar is reduced by 26 ± 2% (standard deviation) during dehydration, but the overall biofilm morphology and analyte distribution are largely retained. We detail a quantitative imaging methodology, in which the ion intensity of each analyte is (1) normalized to an external quadratic regression curve, (2) corrected for isomeric interference, and (3) filtered for sample-specific noise and lower and upper limits of quantitation. The end result is a two-dimensional surface density image for each analyte. The sample preparation and quantitation methods are validated by quantitatively imaging four alkyl-quinolone and alkyl-quinoline N-oxide signaling molecules (including Pseudomonas quinolone signal) in Pseudomonas aeruginosa colony biofilms. We show that the relative surface densities of the target biomolecules are substantially different from values inferred through direct intensity comparison and that the developed methodologies can be used to quantitatively compare as many ions as there are available standards.

A specific, sensitive and stable high-performance liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitative determination of methyl 3-amino-6-methoxythieno [2,3-b]quinoline-2-carboxylate (PU-48), a novel diuretic thienoquinolin urea transporter inhibitor in rat plasma. In this method, the chromatographic separation of PU-48 was achieved with a reversed-phase C 18 column (100 × 2.1 mm, 3 μm) at 35°C. The mobile phase consisted of acetonitrile and water with 0.05% formic acid added with a gradient elution at flow rate of 0.3 mL/min. Samples were detected with the triple-quadrupole tandem mass spectrometer with multiple reaction monitoring mode via electrospray ionization source in positive mode. The retention time were 6.2 min for PU-48 and 7.2 min for megestrol acetate (internal standard, IS). The monitored ion transitions were mass-to-charge ratio (m/z) 289.1 → 229.2 for PU-48 and m/z 385.3 → 267.1 for the internal standard. The calibration curve for PU-48 was linear over the concentration range of 0.1-1000 ng/mL (r 2 > 0.99), and the lower limit of quantitation was 0.1 ng/mL. The precision, accuracy and stability of the method were validated adequately. The developed and validated method was successfully applied to the pharmacokinetic study of PU-48 in rats., (Copyright © 2017 John Wiley & Sons, Ltd.)

The standard method for detecting triple-stranded DNA over the last 1.5 decades has been immune detection using antibodies raised against non-canonical nucleic acid structures. Many fluorescent dyes bind differentially to nucleic acids and often exhibit distinctive staining patterns along metaphase chromosomes dependent upon features, including binding to the major and minor DNA grooves, level of chromatin compaction, nucleotide specificity, and level of dye stacking. Relatively recently, the fluorochrome Thiazole Orange (TO) was shown to preferentially bind to triplex DNA in gels. Here, we demonstrate that TO also detects triplex DNA in salivary gland chromosomes of Drosophila melanogaster and Rhynchosciara americana identical in location and specificity to observations using antibodies. This finding may enable triple-stranded DNA investigations to be carried out on a much broader and reproducible scale than hitherto possible using antibodies, where a frequently encountered problem is the difference in detection specificity and sensitivity between one antibody and another.

Methylated chromenoquinoline dyes were designed and synthesized, and their photophysical properties were investigated. These new fluorescent dyes exhibited relatively high quantum yields, long wavelength emissions, large Stokes shifts, large absorption extinction coefficients and good water-solubility. Importantly, these methylated cation dyes showed a specific staining ability for mitochondria in living cells with low cytotoxicity.

High-performance liquid chromatography (HPLC) coupled in-line with mass spectrometry (MS) permits rapid and specific identification and quantification of N-acyl-L-homoserine lactones (AHLs) and 4-hydroxy-2-alkylquinolines (HAQs). We are presenting here methods for the analysis of these molecules directly from biological samples using LC/MS.

Styryl and/or quinoline structural fragments, present in a large number of bioactive substances, inspired the design of various new drug candidates. In this paper, we describe the photophysical behavior of trans-[2-(4-methoxystyryl)]quinoline-1-oxide (trans-MSQNO) on the basis of X-ray analysis data, theoretical calculations as well as steady state and time-resolved spectroscopy experiments in various media. The molecule crystallizes in orthorhombic unit cell containing eight molecules of N-oxide, space group Pbca. The NO bond is substantially shorter in comparison with the NO bond in the ZnTPP unit [1.3052(11) Å vs. 1.335(2) Å]. Variation of emission colors from the violet (~450nm) through blue (480nm), green (525nm) and yellow (575nm) is observed in different environments. Comparable values of lifetimes estimated both at ambient temperature and at 77K suggest that excited state dynamics in this case is viscosity independent. DFT and TD DFT B3LYP/6-31G(d, p) calculations performed for four different trans-MSQNO rotamers in the gas phase, as well as nonpolar and polar media (PCM model) suggest that an equilibrium between them can be significantly altered even by a relatively weak interactions with the environment. It is suggested that varying intensity ratios of experimental absorption bands in different media may be due to the dominant share of one or more rotamers of the excited trans-MSQNO molecule. Gas phase calculations show also that the vertical ππ*, S 0 →S 1 , transition resulting from the HOMO→LUMO electronic configuration exhibits only a partial CT nature. On the other hand, in polar media, a substantial increment of excited state dipole moment of all rotamers compared to the ground state, its increase with increasing solvent polarity and a significant red shift in the absorption and emission spectra, point to the enhanced CT nature of the S 1 excited state. Hence, the trans-MSQNO molecule may be considered a subsequent styrylquinoline drug candidate where the CT drug-receptor interactions are of a high importance., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The use of synthetic cannabinoids (SC) has been widespread in certain groups of drug users for many years. In the scientific literature many intoxication cases and a number of fatalities after the use of synthetic cannabinoids were reported. In this paper three death cases are described with involvement of the synthetic cannabinoids 5F-PB-22, AB-CHMINACA, and 5F-ADB. The three cases occurred in the eastern region of Germany, which is known as a region of high methamphetamine abuse. All decedents were male, between 25 and 41 years old, and had a known history of drug use. Femoral blood concentrations of the synthetic cannabinoids were measured using a validated LC-MS/MS method. The concentration of 5F-PB-22 in the first case was 0.37ng/mL, the concentration of AB-CHMINACA in the second case was approximately 4.1ng/mL (extrapolated) and the 5F-ADB concentration in the third case was 0.38ng/mL. Compared to other published cases the concentrations in the here presented cases seem to be in the lower range. However, taking into account the scene of death, the results of the forensic autopsy and the full toxicological analysis, the deaths can be explained as a direct consequence of consumption of synthetic cannabinoids, although in case one and two relevant amounts of ethanol were found, and in case three trimipramine and olanzapine were present in non-toxic concentrations. It has to be noted that concentrations of synthetic cannabinoids in femoral blood cannot directly be judged as toxic or lethal due to the possibility of postmortem redistribution and the development of tolerance after frequent use. Therefore, all available information has to be considered carefully before stating SC use as the cause of death., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The lipophilicity of a series of anticancer propargylquinoline derivatives is investigated using both chromatographic and computational methods. The parameters of the tested compounds' relative lipophilicity (logkw) are determined experimentally by the high-performance liquid chromatographic method (RP-HPLC, Accucore C18 column), using mixtures of acetonitrile and water as mobile phases. Mobile phase acetonitrile concentrations range between 50 and 80%. The logk values of the investigated compounds are linearly dependent upon the acetonitrile concentration. The analysis led to the calculation of the logkw parameter values for each of the tested compounds. The parameter logkw is discussed in terms of the relationship between structure and lipophilicity and consequently, transformed into the parameter logPHPLC using the calibration curve. The partition coefficients of the tested compounds (logPcalc) are also calculated by selected computer programs. A regression analysis and the sum of ranking differences are used to compare the lipophilic parameters of 15 acetylenequinoline derivatives, which were experimentally obtained (logPHPLC) and calculated using different mathematical methods (logPcalc). The 13C NMR spectra are used to examine the electronic relationships between properties and lipophilicity for the studied compounds. A regression study conducted on 15 compounds exhibits a linear correlation between lipophilicity and electronic properties, expressed as the 13C NMR chemical shift (R2 = 0.98)., (© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Novel benzimidazoquinoline derivative (AVT) was synthesized through a substitution reaction and characterized by various spectral techniques. Analyzing the optical properties of AVT under absorption and emission spectral studies in different environments exclusively with respect to solvents and pH, intriguing characteristics viz. aggregation induced emission enhancement (AIEE) in the THF solvent and 'On-Off' pH sensing were found at neutral pH. Sensing nature of AVT with diverse metal ions and bovine serum albumin (BSA) was also studied. Among the metal ions, Fe 3+ ion alone tunes the fluorescence intensity of AVT probe in aqueous medium from "turn-on" to "turn-off" through ligand (probe) to metal charge transfer (LMCT) mechanism. The probe AVT in aqueous medium interacts strongly with BSA due to Fluorescence Resonance Energy Transfer (FRET) and the conformational change in BSA was further analyzed using synchronous fluorescence techniques. Docking study of AVT with BSA reveals that the active site of binding is tryptophan residue which is also supported by the experimental results. Interestingly, fluorescent AVT probe in cells was examined through cellular imaging studies using BT-549 and MDA-MB-231 cells. Thus, the single molecule probe based detection of multiple species and stimuli were described., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Quinoxyfen has been recently identified as a priority hazardous substance in the field of the European water policy. In this work, its fate in aqueous samples and solid supports under UV and solar radiation is investigated. Diverse degradation experiments were carried out, at lab scale, using spiked aliquots of different aqueous matrices (ultrapure, treated wastewater and river water) irradiated at different wavelengths (λ = 254 nm, λ = 365 nm and solar light). Half-lives of quinoxyfen (2-26 min) depended on the wavelength and the intensity of radiation whilst the nature of the aqueous matrix did not play an important role in degradation kinetics. Moreover, experiments under solar radiation of doped silicone tubes were performed to simulate degradation when quinoxyfen is adsorbed on plant leaves or soil. As the compound is not completely mineralized, the identification of quinoxyfen transformation products (TPs) was performed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) injection of different irradiated time aliquots. The full-fragment ion spectra, at different collision energies, allowed the elucidation of the chemical structure of TPs formed by hydroxylation, cyclization or cleavage reactions. Five out of seven identified TPs have not been reported previously. The ecotoxicity simulation by software (TEST and ECOSAR) for TPs revealed that some of them could cause harmful effects to organisms such as Daphnia magna or Fathead minnow in a similar extent to the precursor; moreover, the time course profiles of major TPs (TP1 and TP2) revealed a much higher resistance to further photodegradation than quinoxyfen. Graphical abstract Quinoxyfen phototransformation pathways.

A 4,5-quinolimide derivative, BNA, bearing the amide-DPA receptor, was synthesized as a turn-on fluorescent sensor for Cd 2+ . Under physiological conditions, BNA could distinguish Cd 2+ from Zn 2+ , showing turn-on fluorescence behaviour and an increased fluorescence lifetime. BNA and Cd 2+ formed a 1 : 1 stoichiometric complex, and the detection limit was measured to be as low as 11 nM. Furthermore, BNA was utilized for fluorescence imaging of Cd 2+ in live cells. To the best of our knowledge, it is the first 4,5-quinolimide-based sensor for the detection of metal ions.

A new rapid and simple stability-indicating spectrofluorimetric method has been developed for the determination of two irreversible tyrosine kinase inhibitors (TKIs), neratinib (NER) and pelitinib (PEL). The method is based upon measurement of the native fluorescence intensity of both drugs at λ ex 270 nm in aqueous borate buffer solutions (pH 10.5). The fluorescence intensity recorded at 545 nm (NER) and 465 nm (PEL) were rectilinear over the concentration range of 0.1-10 μg/mL for both drugs with a high correlation coefficient (r > 0.999). The proposed method provided low limits of detection and of quantitation of 0.07, 0.11 μg/mL (NER) and 0.02, 0.05 μg/mL (PEL), respectively. The method was successfully applied for the determination of NER and PEL in bulk powder. The proposed methods were fully validated as per the International Conference on Harmonisation (ICH) guidelines. The application of the method was extended to stability studies of both NER and PEL under different forced-degradation conditions (acidic-induced, base-induced, oxidative, wet heat, and photolytic degradation). Moreover, the kinetics of the base-induced and oxidative degradation of both drugs was investigated and the pseudo-first-order rate constants and half-lives were estimated at different temperatures. Also, an Arrhenius plot was applied to predict the stability behaviour of the two drugs at room temperature. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)