Quantification of nine antiretroviral drugs in cerebrospinal fluid: An approach to overcome sample collection tube adsorption.

A highly sensitive LC-MS/MS methods were developed and validated to quantify nine antiretrovirals (atazanavir [ATV], tenofovir [TFV], emtricitabine [FTC], darunavir [DRV], dolutegravir [DTG], efavirenz [EFV], lamivudine [3TC], raltegravir [RAL], and ritonavir [RTV]) in human cerebral spinal fluid (CSF). The approach remedies adsorption issues caused by polypropylene based sample collection tubes. 1% ammonium hydroxide in methanol was added in an amount equal to the volume of each quality control (QC) or patient sample. Protein precipitation was utilized with a CSF sample volume of 100 µL and a 100 µL of methanol:ACN and vortexed. Chromatographic separation was achieved with a 3 × 100 ACE® C18 column for ATV, DRV, DTG, EFV, RTV and RAL, and a 2 × 100 Polar RP column for TFV/FTC/3TC. Mobile phase was methanol:water:formic acid (70:30:0.1, v/v/v) for ATV, DRV, DTG, EFV and RTV (10 uL injection, flow rate: 1.00 mL/min), ACN:water:formic acid (35:65:0.1, v/v/v) for RAL (50 uL injection, flow rate: 1.00 mL/min), ACN:water:formic acid (2:98:0.1, v/v/v) for TFV, FTC and 3TC (50 uL injection, flow rate: 0.35 mL/min). Column temperature was 40° C across all assays. The mass spectrometer was operated in positive, multiple-reaction-monitoring (MRM) mode with electrospray ionization (ESI) for all analytes with the exception of EFV, which was operated in negative, MRM mode with ESI. The assay was linear over the calibration range of 1 to 250 ng/mL for all analytes. The addition of 1% ammonium hydroxide in sample tubes overcame up to 44% negative bias in QC samples and allowed the methods to meet full validation criteria.

Effect of Temperature and H Flux on the NH3 Synthesis via Electrochemical Hydrogen Permeation.

Ammonia is an indispensable commodity and a potential carbon free energy carrier. The use of H permeable electrodes to synthesize ammonia from N2 , water and electricity, provides a promising alternative to the fossil fuel based Haber-Bosch process. Here, H permeable Ni electrodes are investigated in the operating temperature range 25-120 °C, and varying the rate of electrochemical atomic hydrogen permeation. At 120 °C, a steady reaction is achieved for over 12 h with 10 times higher cumulative NH3 production and almost 40-fold increase in faradaic efficiency compared to room temperature experiments. NH3 is formed with a cell potential of 1.4 V, corresponding to a minimum electrical energy investment of 6.6 kWh kg-1 NH 3 ${{_{{\rm NH}{_{3}}}}}$ . The stable operation is attributed to a balanced control over the population of N, NHx and H species at the catalyst surface. These findings extend the understanding on the mechanisms involved in the nitrogen reduction reaction and may facilitate the development of an efficient green ammonia synthesis process.

[An LC-MS/MS Analytical Method for Moenomycin A in Livestock Products].

A simple and sensitive method for the determination of moenomycin A residues in livestock products using LC-MS/MS was developed. Moenomycin A, a residual definition of flavophospholipol, was extracted from samples with a mixture of ammonium hydroxide and methanol (1 : 9, v/v) preheated at 50℃. The crude extracted solutions were evaporated and purified by liquid-liquid partitioning between a mixture of ammonium hydroxide, methanol and water (1 : 60 : 40, v/v/v) and ethyl acetate. The alkaline layer was taken, and cleaned up using a strong anion exchange (InertSep SAX) solid phase extraction cartridge. The LC separation was performed on an Inertsil C8 column with liner gradient elution using 0.3 vol% formic acid and acetonitrile containing 0.3 vol% formic acid. Moenomycin A was detected using tandem mass spectrometry with negative ion electrospray ionization. Recovery tests were conducted using three porcine samples (muscle, fat and liver) and chicken eggs. Samples were spiked with moenomycin A at 0.01 mg/kg and at the Japanese Maximum Residue Limits (MRLs) established for each sample. The trueness ranged from 79 to 93% and precision ranged from 0.5 to 2.8%. The limit of quantification (S/N≥10) of the developed method is 0.01 mg/kg. The developed method would thus be very useful for regulatory monitoring of flavophospholipol in livestock products.

Versatile microbial communities rapidly assimilate ammonium hydroxide-treated plastic waste.

Waste plastic presently accumulates in landfills or the environment. While natural microbial metabolisms can degrade plastic polymers, biodegradation of plastic is very slow. This study demonstrates that chemical deconstruction of polyethylene terephthalate (PET) with ammonium hydroxide can replace the rate limiting step (depolymerization) and by producing plastic-derived terephthalic acid and terephthalic acid monoamide. The deconstructed PET (DCPET) is neutralized with phosphoric acid prior to bioprocessing, resulting in a product containing biologically accessible nitrogen and phosphorus from the process reactants. Three microbial consortia obtained from compost and sediment degraded DCPET in ultrapure water and scavenged river water without addition of nutrients. No statistically significant difference was observed in growth rate compared to communities grown on DCPET in minimal culture medium. The consortia were dominated by Rhodococcus spp., Hydrogenophaga spp., and many lower abundance genera. All taxa were related to species known to degrade aromatic compounds. Microbial consortia are known to confer flexibility in processing diverse substrates. To highlight this, we also demonstrate that two microbial consortia can grow on similarly deconstructed polyesters, polyamides, and polyurethanes in water instead of medium. Our findings suggest that microbial communities may enable flexible bioprocessing of mixed plastic wastes when coupled with chemical deconstruction.

Unintentional poisoning from decanted toxic household chemicals.

BACKGROUND: Although poisonings due to a toxic substance being decanted into a secondary container are often reported to poison centers, we were unable to locate prior European data about their circumstances, incidence and consequences. We sought to describe the circumstances and outcomes of this behavior. MATERIALS AND METHOD: We conducted a prospective study of all poison exposures involving transfer to a secondary container reported to our poison center during a six month interval (January 1, 2021 through June 30, 2021). We called patients and clinicians for follow up the next day. We used a prepared questionnaire and added the responses to the national database for French poison centers. RESULTS: We identified and included 238 patients (104 male, 134 female) with a median age of 39 years [range 0-94 y]. Exposure was mainly oral (n = 221), the secondary container was mainly a water bottle (n = 173), toxic substances were essentially cleaning products (n = 63) or bleach (n = 48). Symptoms were gastrointestinal (vomiting, diarrhea, abdominal pain) (n = 143) or respiratory (cough, dyspnea, aspiration pneumonia) (n = 15). The World Health Organisation/International Programme on Chemical Safety/European Commission/European Association of Poison Centres and Clinical Toxicologists Poisoning Severity Score was none in 76 cases (31.9%), minor in 147 (61.8%), moderate in 12 (5%), and severe in three cases (1.3%). Products that led to severe poisoning contained either ammonium hydroxide or sodium hydroxide. Two of the patients required intensive care treatment. At the end of the follow-up, 235 patients fully recovered, and three patients had sequelae. CONCLUSIONS: The study illustrates the risk of toxic substance transfer. Water bottles were the secondary containers in most exposures to decanted substances. Most had minor or no effects, but nearly one-quarter were admitted to the hospital. The few severe exposures involved either ammonium hydroxide or sodium hydroxide.

Capillary Electrophoresis-Mass Spectrometry for the Direct Analysis of Metabolites in Highly Saline Samples Using In-Capillary Preconcentration.

Capillary electrophoresis-mass spectrometry (CE-MS) is gaining interest for metabolomics studies because of its high separation efficiency, selectivity, and versatility. The ability to inject nanoliters from only a few microliters of sample in the injection vial makes this approach very suited for volume-limited applications. However, the low injection volumes could compromise the detection sensitivity of CE-MS, thereby potentially limiting its scope in metabolomics. To overcome this issue, online sample preconcentration methods have been developed to increase sample-loading volumes without hampering the intrinsic high separation efficiency of CE. In this protocol, online preconcentration with sample stacking based on pH junction was assessed for the direct profiling of endogenous metabolites in rat brain microdialysates. Sample stacking was realized by a pre-injection of ammonium hydroxide, followed by a large sample injection (i.e., about 17% of the total capillary volume). It is shown that this relatively simple and fast preconcentration procedure is fully compatible with the high-salt concentration in microdialysates and significantly improves the detection sensitivity of the CE-MS method.

Effects of Neutralization on the Physicochemical, Mechanical, and Biological Properties of Ammonium-Hydroxide-Crosslinked Chitosan Scaffolds.

It has been reported that chitosan scaffolds, due to their physicochemical properties, stimulate cell proliferation in different tissues of the human body. This study aimed to determine the physicochemical, mechanical, and biological properties of chitosan scaffolds crosslinked with ammonium hydroxide, with different pH values, to better understand cell behavior depending on the pH of the biomaterial. Scaffolds were either neutralized with sodium hydroxide solution, washed with distilled water until reaching a neutral pH, or kept at alkaline pH. Physicochemical characterization included scanning electron microscopy (SEM), elemental composition (EDX), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, thermogravimetric analysis (TGA), and mechanical testing. In vitro cytotoxicity was assessed via dental-pulp stem cells' (DPSCs') biocompatibility. The results revealed that the neutralized scaffolds exhibited better cell proliferation and morphology. It was concluded that the chitosan scaffolds' high pH (due to residual ammonium hydroxide) decreases DPSCs' cell viability.

Agent-assisted electrokinetic treatment of sewage sludge: Heavy metal removal effectiveness and nutrient content characteristics.

Sewage sludge (SS) is rich in nutrient elements such as phosphorus (P), nitrogen (N), and potassium (K), and therefore a candidate material for use in agriculture. But high content of heavy metals (HMs) can be a major obstacle to its further utilization. Therefore, an appropriate HM removal technology is required before its land application. In this study, an innovative biodegradable agent (citric acid, FeCl3, ammonium hydroxide, tetrasodium iminodisuccinate (IDS), and tea saponin) assisted electrokinetic treatment (EK) was performed to investigate the HM removal efficiency (RHMs) and nutrient transportation. Citric acid, IDS, and FeCl3-assisted EK showed a preferable average RHMs (Rave) reduction of 52.74-59.23%, with low energy consumption. After treatment, the content of Hg (0.51 mg kg-1), Ni (13.23 mg kg-1), and Pb (26.45 mg kg-1) elements met the criteria of national risk control standard, in all cases. Following the treatment, most HMs in SS had a reduced potential to be absorbed by plants or be leached into water systems. Risk assessment indicated that the Geoaccumulation index (Igeo) value of HMs has decreased by 0.28-2.40, and the risk of Pb (Igeo=-0.74) reduced to unpolluted potential. Meanwhile, no excessive nutrient loss in SS occurred as a result of the treatment, on the contrary, there was a slight increase in P content (18.17 mg g-1). These results indicate that agent-assisted EK treatment could be an environmentally-friendly method for RHMs and nutrient element recovery from SS, opening new opportunities for sustainable SS recycling and its inclusion into circular economy concepts.

A review of the existing and emerging technologies for wastewaters containing tetramethyl ammonium hydroxide (TMAH) and waste management systems in micro-chip microelectronic industries.

The present work aims to describe and review the available technologies and the recent advancements in treating industrial wastewater containing tetramethylammonium hydroxide (TMAH). It is a quaternary ammonium salt and widely used in the microelectronics industry; this kind of company produces large quantities of wastewater containing TMAH. The exhausted solutions must be treated appropriately since TMAH is corrosive, toxic to human health, and ecotoxic. Regarding the concentration at discharge, currently there are no European regulations. Still, it has been indicated that the substance has a negative influence on the oxygen balance and cause eutrophication, and fall into the relevant categories. In the first part of the work, the available technologies and the recent advancements for the treatment of TMAH contained in industrial wastewater are reviewed. Separation methods as such adsorption, ion exchange, membrane processes, and destruction technologies classified as advanced oxidation processes and biological processes have been considered. In the second part of the manuscript, industrial patented wastewater treatments have been described. Biological processes are those more used, being more economically feasible, require very long times not always sustainable.

Durable antibacterial cotton fabric fabricated using a "self-created" mist polymerization device.

There are two major problems associated with the use of antibacterial cotton fabric. The durability of the fabric is poor, and the inherent properties of the fabric deteriorate following the execution of the finishing processes. These limit the application of antibacterial fabric. We first treated the cotton fabric with acryloyl chloride (AC) molecules to make the surface of the fabric rich in carbon­carbon double (C=C) bonds. Following this, the [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (DMES) monomer was polymerized with the CC bonds on the fabric following the "grafting through" method. As a result, the cotton fabric was successfully grafted with the poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (PDMES), exploiting covalent bonds. The finished fabric exhibited excellent antibacterial effects. The bacterial reduction (BR) rates of the finished fabric against E. coli and S. aureus were greater than 99.0 %. Even after 50 washing cycles, the BR rates of the finished fabric against E. coli and S. aureus were greater than 96.0 %. In addition, the use of the "self-created" mist polymerization technology ensured that the inherent properties of the finished fabric were retained to a large extent. Therefore, the antibacterial cotton fabric prepared following this method can be potentially used for the fabrication of industrial and household textiles.

The effect of pH adjusted electrolytes on capillary isoelectric focusing assessed by high-resolution dynamic computer simulation.

The effect of the composition of electrolytes on capillary IEF is assessed for systems with carrier ampholytes covering two pH units and with catholytes of decreased pH, anolytes of increased pH, and both electrode solutions with adjusted pH values. For electrolytes composed of formic acid as anolyte and ammonium hydroxide as catholyte, simulation is demonstrated to provide the expected IEF system in which analytes with pI values within the formed pH gradient are focused and become immobile. Addition of formic acid to the catholyte results in the formation of an isotachophoretic zone structure that migrates toward the cathode. With ammonium hydroxide added to the anolyte migration occurs toward the anode. In the two cases, all carrier components and amphoteric analytes migrate isotachophoretically as cations or anions, respectively. The data reveal that millimolar amounts of a counter ion are sufficient to convert an IEF pattern into an ITP system. With increasing amounts of the added counter ion, the overall length of the migrating zone structure shrinks, the range of the pH gradient changes, and the migration rate increases. The studied examples indicate that systems of this type reported in the literature should be classified as ITP and not IEF. When both electrolytes are titrated, a non-uniform background electrolyte composed of formic acid and ammonium hydroxide is established in which analytes migrate according to local pH and conductivity without forming IEF or ITP zone structures. Simulation data are in qualitative agreement with previously published experimental data.

Ionic homeostasis, biochemical components and yield of Italian zucchini under nitrogen forms and salt stress / Homeostase iônica, componentes bioquímicos e produção da abobrinha italiana sob formas de nitrogênio e estresse salino

This research was carried out aiming at evaluating the effects of nitrate and ammonium ions on nutrient accumulation, biochemical components and yield of Italian zucchini (cv. Caserta) grown in a hydroponic system under salt stress conditions. The experiment was carried out in a greenhouse utilizing an experimental design in randomized blocks, arranged in a 2 x 5 factorial scheme, with 4 replications. The treatments consisted of two forms of nitrogen (nitrate - NO3- and ammonium - NH4+) and 5 electrical conductivity levels of irrigation water (ECw) (0.5, 2.0, 3.5, 5.0 and 6.5 dS m-1). The analysis of the results indicated that supply of N exclusively in NH4+ form promotes greater damage to the leaf membrane and reduction in accumulation of macronutrients and higher Na+/K+, Na+/Ca++ and Na+/Mg++ ratios in the shoots of zucchini plants. Electrical conductivity of irrigation water above 2.0 dS m-¹ reduces the accumulation of nutrients in shoot and yield of Italian zucchini plant. The toxicity of NH4+ under Italian zucchini plants overlap the toxicity of the salinity, since its fertilization exclusively with this form of nitrogen inhibits its production, being the NO3- form the most suitable for the cultivation of the species.

Este trabalho foi desenvolvido com o objetivo de avaliar os efeitos dos íons nitrato e amônio sobre o acúmulo de nutrientes e produção da abobrinha italiana (cv. Caserta) cultivada em sistema hidropônico sob estrese salino. O experimento foi conduzido em casa de vegetação utilizando o delineamento experimental em blocos casualizados, arranjados em esquema fatorial 2 x 5, com 4 repetições. Os tratamentos foram constituídos de duas formas de nitrogênio (nitrato - NO3- e amônio - NH4+) e cinco níveis de condutividade elétrica da água de irrigação (CEa) (0,5; 2,0; 3,5; 5,0 e 6,5 dS m-¹). As análises dos resultados indicaram que suprimento de N exclusivamente em forma de NH4+ promove maiores danos na membrana foliar e redução no acúmulo de macronutrientes e maiores relações Na+/K+, Na+/Ca++ e Na+/Mg++ na parte aérea das plantas de abobrinha. A irrigação com água a cima de 2,0 dS m-¹ reduz o acúmulo de nutrientes na parte aérea das plantas e a produção de abobrinha. A toxicidade do NH4+ sob abobrinha italiana sobrepõe-se à toxicidade da salinidade, pois a fertilização exclusiva com esta forma de nitrogênio inibe sua produção, sendo a forma NO3- a mais adequada para o cultivo da espécie.

Sub/supercritical Fluid Chromatography Purification and Desalting of a Cyclic Dinucleotide STING Agonist.

An efficient and "endotoxin-free" purification of a cyclic dinucleotide (CDN) STING agonist was achieved to produce multigram quantities of pure BMT-390025, an active pharmaceutical ingredient (API), for toxicological studies. A two-step sub/supercritical fluid chromatography (SFC) procedure was developed for the achiral purification and desalting of the polar ionic CDN. A robust SFC process employing methanol-acetonitrile-water with ammonium acetate as co-solvent in CO2 on BEH 2-ethylpyridine was established and scaled up as the first step to achieve a successful purification. The desalting/salt-switching (i.e. removing acetate and acetamide) was conducted using methanol-water with ammonium hydroxide as co-solvent on the same column in the second step to convert the final API to the ammonium salt. Water with additive was essential to eliminating salt precipitation and improving the peak shape and resolution. Due to the extreme hydrophilicity of BMT-390025, 65% of co-solvent was needed to adequately elute the target in both steps. More than 40 g of crude API was purified and desalted producing >20 g of pure BMT-390025 as the ammonium salt which was obtained with a chemical purity of >98.5% and met the endotoxin requirement of <0.1 EU/mg. In addition, >80 g of its penultimate prior to the deprotection of the silyl group was purified at a high throughput of 6.3 g/h (0.42 g/day/g SP).

Large-scale supercritical fluid chromatography purification of unstable STING agonist intermediates.

A regioisomeric mixture of the nucleoside derivative, Intermediate 1, required resolution by preparative supercritical fluid chromatography (SFC) in order to obtain the desired regioisomer as a key intermediate in a STING agonist program. Various chiral columns and solvents including methanol, acetonitrile, isopropanol, and the mixture of acetonitrile and isopropanol as organic modifiers in carbon dioxide at different temperatures were screened to obtain the best regioisomeric resolution. A key issue associated with interconversion between the regioisomers via silyl migration during purification was investigated in methanol, acetonitrile, and the mixture of acetonitrile and isopropanol, and the optimal organic modifier in CO2 was established to mitigate the interconversion to an acceptable level (<5%). Taking into account peak resolution, throughput, interconversion and operation robustness, an efficient SFC method for large-scale purification was successfully developed and scaled up onto a 5 cm I. D. Chiralcel OJ-H column using 25% acetonitrile: isopropanol [1:1 (v/v)] with 0.1% ammonium hydroxide as the modifier in CO2 at a total flow rate of 270 mL/min and a temperature of 30°C. In addition, continual evaporation (i.e. every hour) of the desired isomer fraction stream post-separation ensured minimal further interconversion. A total of 258 grams were separated at a high throughput of 8.6 g/h. Regioisomeric purity of the desired isomer of Intermediate 1 was ≥98.2% and the recovery was ≥90.2%. A similar purification strategy was applied to the regioisomeric resolution of Intermediate 2, an analog of Intermediate 1. In total, 1028 grams of Intermediate 2 were processed at a high throughput of 12.5 g/h on a Viridis BEH 2-EP column. The regioisomeric purity of the desired isomer was ≥96.8% and the recovery was ≥90.7%.

The effect of column history in supercritical fluid chromatography: Practical implications.

Long-term stability of retention times of a wide range of analytes has been evaluated using eight different stationary phases. These were from a single manufacturer to minimize the differences in silanol activity caused by the manufacturing process. The tested stationary phases included bridge ethylene hybrid, 2-ethylpyridine bridge ethylene hybrid with direct modification of silica particles, bidentate crosslinked charged surface hybrid fluorophenyl, bidentate crosslinked high strength silica C18, and propanediol linked phases including diol (pure propanediol linker), and three phases based on diol further modified with 2-picolylamine, diethylamine, and 1-aminoanthracene group. Retention times were monitored at the first injection, after three, nine, twelve months, and after the column regeneration via washing with pure water. The analyses were carried out using three different mobile phases, including methanol, methanol with 10 mmol/L ammonium formate, and methanol with 0.1% ammonium hydroxide. No overall decreasing or increasing trends were observed after evaluating individual contributing parameters such as analyte, stationary phase, and organic modifier. Our results suggest that the silyl-ether formation is not the only factor contributing to changes in the stationary phase pore surface. Indeed, the adsorption of mobile phase additives is probably another significant factor. That was also confirmed by the regeneration procedure using water, which is likely to reverse the silyl-ether formation to achieve the original retention. However, the retention times returned to the original values for all analytes only on three columns. Retention times on other columns remained shifted within ± 15 % RSD depending on the analyte properties and the nature of organic modifier. The retention time variations observed for each analyte group, i.e., acids, bases, and neutrals, were interpreted for each stationary phase. We concluded that the sterically protected surfaces exhibited significantly smaller changes in the retention times. Although the regeneration procedure effect depended on the column type, the results suggested beneficial effect of water. However, as the adsorption of additives on the column surface is an additional factor leading to retention time variations, the recommendation of using only one additive and/or organic modifier in each column will clearly improve the long-term repeatability of the retention times.

Optimized Extraction of Amikacin from Murine Whole Blood.

Amikacin (Amk) analysis and quantitation, for pharmacokinetics studies and other types of investigations, is conventionally performed after extraction from plasma. No report exists so far regarding drug extraction from whole blood (WB). This can represent an issue since quantification in plasma does not account for drug partitioning to the blood cell compartment, significantly underrating the drug fraction reaching the blood circulation. In the present work, the optimization of an extraction method of Amk from murine WB has been described. The extraction yield was measured by RP-HPLC-UV after derivatization with 1-fluoro-2,4-dinitrobenzene, which produced an appreciably stable derivative with a favorable UV/vis absorption. Several extraction conditions were tested: spiked Amk disulfate solution/acetonitrile/WB ratio; presence of organic acids and/or ammonium hydroxide and/or ammonium acetate in the extraction mixture; re-dissolution of the supernatant in water after a drying process under vacuum; treatment of the supernatant with a solution of inorganic salts. The use of 5% (by volume) of ammonium hydroxide in a hydro-organic solution with acetonitrile, allowed the almost quantitative (95%) extraction of the drug from WB.

Kinetic Behavior of Quaternary Ammonium Hydroxides in Mixed Methane and Carbon Dioxide Hydrates.

This study evaluates the kinetic hydrate inhibition (KHI) performance of four quaternary ammonium hydroxides (QAH) on mixed CH4 + CO2 hydrate systems. The studied QAHs are; tetraethylammonium hydroxide (TEAOH), tetrabutylammonium hydroxide (TBAOH), tetramethylammonium hydroxide (TMAOH), and tetrapropylammonium hydroxide (TPrAOH). The test was performed in a high-pressure hydrate reactor at temperatures of 274.0 K and 277.0 K, and a concentration of 1 wt.% using the isochoric cooling method. The kinetics results suggest that all the QAHs potentially delayed mixed CH4 + CO2 hydrates formation due to their steric hindrance abilities. The presence of QAHs reduced hydrate formation risk than the conventional hydrate inhibitor, PVP, at higher subcooling conditions. The findings indicate that increasing QAHs alkyl chain lengths increase their kinetic hydrate inhibition efficacies due to better surface adsorption abilities. QAHs with longer chain lengths have lesser amounts of solute particles to prevent hydrate formation. The outcomes of this study contribute significantly to current efforts to control gas hydrate formation in offshore petroleum pipelines.

Preparation of carbon dots from waste cellulose diacetate as a sensor for tetracycline detection and fluorescence ink.

As one type of the solid wastes, the increasing contamination of waste cellulose diacetate (CDA) from discarded cigarette filters is a growing problem worldwide. Finding a facile and suitable approach to convert the CDA into value-added materials is of significance. Herein, we reported a green, simple and effective method to reuse CDA as precursor for preparing fluorescence N-doped carbon dots (N-CDs) via one-pot hydrothermal carbonization in aqueous solution with low-cost ammonium hydroxide as the passivation agent. The N-CDs showed a quantum yield up to 22.4% with a maximum emission at 415 nm and excitation at 320 nm. Interestingly, the N-CDs exhibited high selectivity toward tetracycline (TC) as their fluorescence was obviously quenched by TC as a result of inner-filter effect. A linear relationship was fabricated over concentration range of 0-80 µM with a detection limit of 0.06 µM. Moreover, the N-CDs could also be applied as fluorescent ink for anti-forgery.

Highly efficient recovery of molybdenum from spent catalyst by an optimized process.

Disposal of spent catalyst in an economical and green way has become a great concern for industrial production. We developed a process including acid leaching, solvent extraction and stripping in order to recycle spent catalyst. In this study, we conducted selective recovery of molybdenum through focus on finding an optimized extraction and stripping process by comparing different extractants and stripping agents. To separate molybdenum from other metals efficiently and figure out the mechanism of extraction process, the five different extractants of methyl trioctyl ammonium chloride, tri-n-octylamine, tris (2-ethylhexyl) amine, bis (2-ethylhexyl) phosphate, and tributyl phosphate with different functional groups were examined; the extraction ability and extraction mechanism of these five extractants were systematically studied under the same system for the first time. It was found that more than 98% of the molybdenum could be extracted with an organic phase consisting of tri-n-octylamine or methyl trioctyl ammonium chloride under the optimal conditions. The result indicated that the tri-n-octylamine and methyl trioctyl ammonium chloride possess excellent molybdenum extraction ability, the extraction capacity of the rest extractants was in the order of bis (2-ethylhexyl) phosphate > tris (2-ethylhexyl) amine > tributyl phosphate. In the stripping process, NH4OH, NaOH, and H2SO4 were chosen as stripping agent to strip the molybdenum from the loaded tri-n-octylamine organic phase. The stripping ability of the three studied stripping agents was in the order NaOH > NH4OH > H2SO4. The Fourier transform infrared (FTIR) spectra showed that the structure of the tri-n-octylamine organic phase was stable during the extraction and stripping process. Results showed that molybdenum could be highly and efficiently recovered by optimized extraction and stripping process. Implications: A series of different extractants and stripping agent have been systematically studied in order to compare their extraction and stripping ability under the same system. Based on the obtained results, an optimized extraction and stripping process was proposed to recycle molybdenum from spent catalyst efficiently. It is possible to dispose spent catalysts in an economic and environmental way by this developed metal recovery process.

Formalin pigment artifact deposition in autopsy tissue: predisposing factors, patterns of distribution and methods for removal.

Formalin pigment deposition is a known artifact of autopsy histology, often anecdotally associated with decomposition of bodies. However, there is minimal data within the forensic literature demonstrating an association between formalin pigment deposition and length of postmortem interval. Furthermore, there is minimal data concerning other predisposing factors and patterns of distribution of formalin pigment deposition. In this study, we compare the amount and patterns of formalin deposition on histology slides from three categories of death: 1) decomposed bodies, 2) critically ill at time of death, and 3) sudden cardiac death. We also compare the effectiveness of two relatively simple histology laboratory methods to remove formalin pigment deposition from histology slides. Amongst the three categories of death, formalin deposition was highest in the decomposed category, second highest in the critically ill category, and lowest in the sudden cardiac death category. The organs most severely affected by formalin deposition were liver/spleen/pancreas and kidneys, and the organs least affected were brain and lung. Formalin pigment deposition correlated with length of postmortem interval. Histologic patterns of formalin deposition included the endothelial lining of vessels, perinuclear compartment of neurons and myocytes, and the basal epithelial compartment of renal tubular epithelial cells. The alcoholic ammonium hydroxide method (AAH) was slightly more effective than the alkylphenol ethoxylate (APE) method for removing formalin pigment, though both methods were effective. Because formalin pigment is strongly refractile under polarized light, a polarization filter can also be useful for distinguishing formalin pigment from other pigments.