Solid Phase Research Articles

Porous Polymer Sorbents in Micro Solid Phase Extraction: Applications, Advantages, and Challenges

Porous Polymer Sorbents in Micro Solid Phase Extraction: Applications, Advantages, and Challenges

Computational integration and experimental validation of a two-length scale model for accurate prediction of steels’ plastic behavior during phase transformation

Transformation plasticity, essential during solid–solid phase transitions, significantly impacts industrial processes like welding and quenching. Accurately simulating these procedures necessitates understanding thermal, metallurgical, and mechanical effects. Leblond et al.’s model offers a foundation, but refinement for mixed isotropic/kinematic hardening is crucial. We enhance this model by introducing characteristic length scales through nonlocal variables, illuminating plastic deformation mechanisms in both phases. Our work includes numerical implementation within a finite element analysis framework and practical applications to phase transformation scenarios involving A.508 cl. 3 and A533 low-alloy steels. Results affirm model robustness and efficiency in predicting phase transformation phenomena, benefiting industrial applications.

Exploring peptide dendrimers for intestinal lymphatic targeting: formulation and evaluation of peptide dendrimer conjugated liposomes for enhancing the oral bioavailability of Asenapine maleate.

Asenapine maleate (ASPM) is a second-generation atypical antipsychotic that is approved for treating acute schizophrenia and bipolar disorder in adults by the US FDA. The major downside of ASPM therapy is rapid, extensive first-pass hepatic metabolism following its oral administration with a very low oral bioavailability of < 2%. In this work, we developed ASPM nanoformulations conjugated with ligands such as arginine-glycine-aspartic acid (RGD) and peptide dendrimers (PDs) with the intention of improving the oral bioavailability of the drug by targeting it to the intestinal lymphatic system (ILS). Peptide dendrimers (PDs), both lipidated and nonlipidated, were synthesized by Fmoc solid phase peptide synthesis (SPPS). Reverse phase high performance chromatography (RP-HPLC) was used to purify the synthesized PDs, and the PDs were characterized by differential scanning calorimetry (DSC) electrospray ionization mass spectroscopy (ESI+-MS), Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy. The thin film hydration method was used to prepare liposomes, and the process variables affecting the liposome parameters were optimized using the Box‒Behnken design (BBD).Liposomes were PEGylated using DSPE-PEG-COOH2000 and further conjugated with ligands (RGD, PD-1 and PD-2) using EDC-NHS chemistry. The formulation was characterized using different spectroscopic techniques. In vitro, cell line studies, such as cytotoxicity, cell uptake, uptake mechanism, and receptor saturation studies, were performed on both Caco2 and Raji-B cells. The pharmacokinetic parameters of the developed liposomal formulation were evaluated using pharmacokinetic studies on Sprague- Dawley (SD) rats. The psychostimulant-induced hyperactivity model was used to evaluate the pharmacodynamic performance of the developed formulations by measuring the reversal of hyperlocomotor activity induced by levodopa-carbidopa.

The effect of single walled carbon nanotubes on conductivity and thermal properties of glass fiber reinforced composites

Abstract This paper reports on a comprehensive study of the effect of single-walled carbon nanotube (SWCNT) on the alternating current (AC) conductivity, thermal and morphological properties of the unsaturated polyester based glass fiber reinforced polymer composite (GFRPC). AC conductivity measurements were carried out using the impedance spectrum and thermal measurements were carried out using differential scanning calorimetry (DSC) at a temperature range of 24-900 °C and heating rates of 20 °C/min. Impedance results showed that the conductivity behavior in the nanotube-loaded composite laminate obeys a Jonscher-type mechanism. At low frequencies, the conductivity value remains almost constant for the doped material and takes the value of 10-5 S/cm. It is observed that the AC conductivity starts to increase after the critical frequency value of approximately 103 Hz and increases up to 10-2 S/cm due to hopping and tunneling mechanisms caused by space charge polarization accumulated in the local regions at high frequencies. The pure material with an insulating nature also exhibited a typical insulating behavior. Thermal testing showed that nanotube reinforcement increases thermal conductivity in three different directions. DSC thermocurves analysis also revealed that the addition of carbon nanotubes increased the glass transition temperature of the material from 180°C to 190°C. The scaling and fractal analysis methods were also applied to obtain hetero morphological structure of materials. The fractal analysis results indicated that carbon nanotube doping to the standard sample increases the coating rates, scalability and heterogeneity of the solid phase surface of the sample. The coating rates of composite surfaces were calculated as 45% and 36%, respectively. Morphology analysis revealed that the probability of finding surface particles for the nanotube-doped sample decreased compared to the undoped sample, but the fractal dimension value increased. While this value was 1.83 in the pure sample, it increased to 1.92 in the nanotube material.

Pharmacokinetic-Pharmacodynamic Modeling of the Immune-Enhancing Effect of Shikimic Acid in Growing Pigs.

Shikimic acid (SA), extracted from the fruit of shikimi-no-ki, is used both as a preservative in the food industry and as an intermediate for a variety of active ingredients with a wide range of pharmacological functions. A deeper understanding of the pharmacokinetic process of SA in pigs and its impact on humoral immunity could prove invaluable in facilitating its clinical application in veterinary and human medicine. The pharmacokinetic study employed a two-period, two-sequence, crossover design to animal experiments and developed a novel method of pig plasma preparation using water as an extractant and ionization promoter, followed by purification and enrichment on a MAX solid phase extraction (SPE) column. The results showed that SA is rapidly absorbed after intragastric administration (50 mg/kg BW), reaching a plasma Cmax of 10,823.44 ng/mL at 1.78 h, followed by rapid elimination, with a t1/2 of 1.81 h, consistent with a one-compartment model. The results for intravenous administration (2 mg/kg BW) were consistent with a two-compartment open model with a t1/2 of 3.66 h, with concentrations below the limit of quantification (LOQ) observed beyond 12 h postdose. The absolute bioavailability of SA in pigs was calculated to be 21.68%. Furthermore, the Pearson's correlation analysis demonstrated a strong positive correlation between SA concentration in pig plasma and the changes of C3, C4 and IgG, IgA, and IgM (0.6 < R < 1, P < 0.0001). A more detailed pharmacokinetic-pharmacodynamic (PK-PD) modeling analysis of the intravenous group revealed the EC50/Cmax values of approximately 10%, with all γ values exceeding 3. This study was the inaugural investigation into the pharmacokinetics of SA in growing pigs, and it also revealed that SA has the potential to act as an immunopotentiator.

Generalized Effective Stress of Dual-Porosity Geomaterials Considering Thermochemical Effects

The accurate calculating of effective stress is crucial to predicting soil deformation and ensuring structural safety under complex mechanical, thermal, and chemical loads. In this study, the thermodynamic pressures of the solid phase, and liquid phases in macropores and micropores of dual-porosity geomaterials are determined on the basis of thermodynamics and conservation equations with considering for the impact of temperature and solute concentration on soil-water interactions. In particular, thermal pressurization related to temperature, and generalized osmotic pressure related to solute concentration were incorporated into the liquid-phase thermodynamic pressure equations. Thereafter, an equation for the generalized effective stress that could be applied specifically to dual-porosity geotechnical materials with consideration for environmental loads was derived from the definition of the stress tensor. The deformation behavior of clay under mechanical, thermal, and chemical coupling loading conditions was predicted using the newly proposed generalized effective stress. Predicted results revealed a stronger correlation between the generalized effective stress and void ratio, thereby confirming the accuracy and effectiveness of the proposed approach. The derived equation establishes a solid theoretical foundation for designing impermeable buffer barriers in geotechnical engineering and geo-environmental engineering safety assessments.

Study of the Influence of the Mean Particle Diameter Choice and the Fractions Number on the Quality of Fluidized Bed Numerical Simulation

We investigate the choosing of the fractions number for numerical simulation of a polydisperse bubbling fluidized bed using the Sauter mean diameter. The results were verified using experiments from a glass tube with a diameter of 2.2 cm and a height of 50 cm. As a fluidizing agent, air with a velocity of 0.0716 m/s to 0.1213 m/s was used. Polydispersed aluminum oxide particles with a diameter size of 20–140 µm were used as a solid phase. We propose a simple method for choosing the fractions number for the polydispersed granular phase in order to improve the quality of the numerical simulation results. In this study, we consider the Sauter mean diameter D32 for each selected group of particles for the solid phase. By increasing the number of solid phase fractions, it is possible to obtain a mean boundary of the bubbling fluidized bed close to the observed experimental results. In our study, the division of polydispersed powder into four distinct solid-phase fractions enabled us to attain satisfactory agreement with experiments regarding the average value of the bed boundary.

Photo-Accelerated Synthesis of Oligo(triazole amide)s.

A photo-assisted process is explored for improving the synthesis of oligo(triazole amide)s, which are prepared by solid phase synthesis using a repeated cycle of two reactions: amine-carboxylic acid coupling and copper-catalyzed azide-alkyne cycloaddition (CuAAC). The improvement of the second reaction is investigated herein. A catalytic system involving Cu(II)Cl2, N,N,N',N″,N″-pentamethyldiethylenetriamine (PMDETA)and a titanocene photoinitiator is explored for reducing the reaction time of CuAAC. This catalyst is first tested on a model reaction involving phenylacetylene and ethyl azidoacetate in DMSO. The kinetics of these model experiments are monitored by 1H NMR in the presence of different concentrations of the photoinitiator. It is found that 30 mol% of photoinitiator leads to quantitative reactions in only 8 min. These conditions are then applied to the solid phase synthesis of oligo(triazole amide)s, performed on a glycine-loaded Wang resin. The backbone of the oligomers is constructed using 6-heptynoic acid and 1-amino-11-azido-3,6,9-trioxaundecane as submonomers. Due to slow reagent diffusion, the CuAAC step required more time in the solid phase than in solution. Yet, one hour only is necessary to achieve quantitative CuAAC on the resin, which is twice as fast as previously-reported conditions. Using these optimized conditions, oligo(triazole amide)s of different length are prepared.

Properties of Al0.5CoCrFeNi2Ti High-Entropy Alloy System: From Gas-Atomized Powders to Atmospheric Plasma-Sprayed Coatings

AbstractThe performance of the Al0.5CoCrFeNi2Ti HEA atmospheric plasma-sprayed coating was extended from characterizing the properties of its powder prepared via the gas atomization method. It was observed that the gas-atomized HEA powders possessed a solid solution BCC phase, while a major phase transformation to a FCC-L21 intermetallic phase occurred during the annealing process. The formation of the intermetallic phase resulted in an increase in average hardness from 6.28 to 7.64 GPa after annealing at 900 °C for 1 h. Afterward, HEA powders were applied in the atmospheric plasma spray technology. The phase constitution of Al0.5CoCrFeNi2Ti HEA coatings was investigated by varying powder size and applied current. It was observed that the smaller powder sizes prone to oxidation, whereas higher applied current facilitated the phase transformation from BCC to FCC phase. The nanoindentation test indicated distinct average microhardness values for the interlamellar oxide region, BCC unmelted particle and FCC phase lamellar region, which was measured at 12.35, 8.68 and 5.97 GPa, respectively. As a result, the adjustability of coating hardness was achieved by manipulating the relative phase ratio.

Comparative volatiles profiling of two marjoram products via GC-MS analysis in relation to the antioxidant and antibacterial effects.

Marjoram (Origanum majorana L.), also known as "sweet marjoram" or "sweet oregano" is a Mediterranean herbaceous perennial herb cultivated in Egypt and widely consumed as an herbal supplement for treatment of several ailments. The main goal of this study was to assess volatiles' variation in marjoram samples collected from two different widely consumed commercial products using two different extraction techniques viz. head space solid phase microextraction (HS-SPME) and petroleum ether using gas chromatography mass spectrometry (GC-MS) analysis and multivariate data analysis. A total of 20 major aroma compounds were identified in samples extracted with HS-SPME found enriched in monoterpene hydrocarbons and oxygenated compounds. The major volatiles included β-phellandrene (20.1 and 14.2%), γ-terpinene (13.4 and 11.7%), 2-bornene (12.3 and 11.5%), p-cymene (9.8 and 4.6%) terpenen-4-ol (16.4 and 7.5%), sabinene hydrate (16.02 and 8.8%) and terpineol (4.2 and 3.2%) in MR and MI, respectively. Compared with HS-SPME, 51 aroma compounds were identified in marjoram samples extracted with petroleum ether, found more enriched in aliphatic hydrocarbons (42.8 and 73.8%) in MR and MI, respectively. While a higher identification score was observed in the case of solvent extraction, SPME appeared to be more selective in the recovery of oxygenated terpenes to account more for marjoram aroma. Multivariate data analysis using principal component analysis (PCA) revealed distinct discrimination between volatile composition of both marjoram samples. The total phenolic and flavonoid contents in marjoram samples were at (111.9, 109.1µg GA/mg) and (18.3, 19.5µg rutin eq/mg) in MR and MI, respectively. Stronger antioxidant effects were observed in MR and MI samples with IC50 at 45.5 and 56.8µg/mL respectively compared to IC50 6.57µg/mL for Trolox as assayed using DPPH assay. Moderate anti-bacterial effect was observed in MR and MI samples and expressed as a zone of inhibition mostly against Bacillus subtilis (16.03 and 15.9mm), B. cereus (12.9 and 13.7mm), Enterococcus faecalis (14.03 and 13.97mm), and Enterobacter cloacae (11.6 and 11.6mm) respectively.

Sustainability assessment in food analysis: the application of Green Analytical Chemistry tools to phthalate residue analysis in edible oils

Edible oils are essential in daily diet due to their high contribution of fatty acids, fat-soluble vitamins, and triglycerides. During the processes of growing, processing, storage, transport, or packaging, they can be contaminated by ubiquitous phthalate esters, considered endocrine disruptors. Thus, analytical methodologies to allow tight control of their presence are mandatory. Several sample treatments have been considered in this study: microwave-assisted extraction (MAE), liquid-liquid extraction (LLE), dispersive solid phase extraction (DSPE), magnetic SPE (MSPE), solid phase microextraction (SPME), Surface-enhanced Raman spectroscopy (SERS) or its combinations. However, the selection of an analytical procedure is usually performed from an Analytical Chemistry perspective, without considering factors such as the sustainability of the selected methodology and/or its impact on the environment. In this sense, the Green Analytical Chemistry strategy can play an important role. To demonstrate this fact, six different analytical procedures have been evaluated in terms of sustainability by using several greenness evaluation tools. Procedures from MAE-gel permeation chromatography (GPC)-SPE till SERS, showing adequate analytical characteristics, have been selected. The application of Analytical GREEnness calculator (AGREE), AGREE preparation (AGREE prep), and blue applicability grade index (BAGI) tools showed that MAE-GPC-SPE was the less green analytical procedure while SERS was the greener one. The BAGI evaluation showed that headspace (HS) and SERS were the most applicable procedures.

Abstract 4124070: Dual-action Nanomatrix Coated Stent for Improving Endothelialization while Suppressing Restenosis and Inflammation

Introduction: The most common cause of cardiovascular disease (CVD) is atherosclerosis. The progression of atherosclerosis is characterized by endothelial cell dysfunction, proliferation of smooth muscle cell proliferation, and plaques which lead to progressive arterial stenosis. Bare metal stents (BMS) were developed to hinder stenosis, but re-stenosis has been observed following deployment. Drug-eluting stents (DES) have been developed to mitigate this, by releasing anti-proliferative drugs to suppress smooth muscle cell proliferation. However, these drugs also suppress endothelial growth. To address this, we are developing and evaluating a dual action nanomatrix coated stent comprised of a nitric oxide (NO) releasing peptide amphiphile (PA) and everolimus-encapsulated liposomes to improve endothelial proliferation and suppressing smooth muscle cell proliferation and inflammation. Materials and Methods: The nanomatrix coating contains a PA generated via solid phase peptide synthesis consisting of a nitric oxide donor and a cell adhesive ligand. The everolimus-encapsulated liposomes were prepared with DPPC, DOTAP, DSPE-PEG, and cholesterol via thin film rehydration, followed by encapsulation with everolimus. TEM was performed on liposomes to assess their stability. The release kinetics were evaluated via UV-vis of samples containing released everolimus. To evaluate the dual effect of the nanomatrix coating on metabolism, NO and everolimus were used to treat endothelial and smooth muscle cells, and an MTT assay was done. Results and Discussion: TEM showed that liposomes maintained stability over time. It was found that 60% of everolimus was released by day 30. The MTT assay showed that NO with everolimus increased endothelial cell metabolic activity and maintained or lowered smooth muscle cell activity compared to everolimus alone. Conclusions: Everolimus-encapsulated liposomes have potential as an effective delivery method of everolimus. NO and everolimus have a synergistic effect of improving endothelial function and suppressing smooth muscle cells.

Comparison of biocrude production and characterization from Persian Gulf Sargassum angustifolium macroalgae, Chlorella vulgaris, and Spirulina sp. microalgae using hydrothermal liquefaction (HTL): Potential of solid residue for heavy metal adsorption.

Biocrude production using the hydrothermal liquefaction (HTL) process is a promising alternative energy source to conventional fossil fuels. Using algal feedstock types in this process has many advantages, such as not needing to dry a high moisture content, which consumes much energy. In this study, the feedstock types of Sargassum angustifolium macroalgae, Chlorella vulgaris, and Spirulina sp. microalgae affected the yield and property of the biocrude products were obtained at 350 °C, 18 MPa, 35 min residence time, and 8.7 wt% feedstock concentration. The biocrude yields from Sargassum angustifolium, Chlorella vulgaris, and Spirulina sp. were 26.15 wt%, 55.8 wt%, and 56.32 wt%, respectively. These values revealed that feedstock's carbon and nitrogen contents have the most effect on the biocrude yield, and increasing these elements increases the biocrude yields. Moreover, the properties of the produced biocrudes revealed that the main components were esters, organic acids, ketones, aldehydes, aromatic rings, amides, amines, alcohol, and phenol. The thermal gravimetric analysis (TGA) results of biocrudes showed the decomposition of more organic components at the 175-600 °C temperature range. Also, the simulated distillation of biocrudes showed that most biocrude components from Sargassum angustifolium and Chlorella vulgaris are the same as heavy naphtha, and the biocrude from Spirulina sp. is similar to kerosene. These results showed that the produced biocrude from Chlorella vulgaris has a higher yield and quality than other resources. The quality of the biocrude produced from Sargassum angustifolium is comparable to other biocrudes. Besides, the higher solid-phase yield produced from Sargassum angustifolium was used as a heavy metal biosorbent. The effect of adsorbent concentration and adsorption time on adsorption efficiency was investigated. Results showed that the maximum adsorption efficiency of Fe2+, Zn2+, and Mn2+ was 47.07 wt%, 48.93 wt%, and 42.47 wt%, respectively, at 2 g/L adsorbent concentration and 60 min adsorption time, and the structure destruction of the solid phase was carried out under the biosorption process.

Kinetics of γ-LiAlO2 Formation out of Li2O-Al2O3 Melt—A Molecular Dynamics-Informed Non-Equilibrium Thermodynamic Study

Slags generated from pyrometallurgical processing of spent Li-ion batteries are reservoirs of Li compounds that, on recycling, can reintegrate Li into the material stream. In this context, γ-LiAlO2 is a promising candidate that potentially increases recycling efficiency due to its high Li content and favorable morphology for separation. However, its solidification kinetics depends on melt compositions and cooling strategies. The Engineered Artificial Minerals approach aims to optimize process conditions that maximize the desired solid phases. To realize this goal, understanding the coupled influence of external cooling kinetics and internal kinetics of solid/liquid interface migration and mass and thermal diffusion on solidification is critical. In this work, the solidification of γ-LiAlO2 from a Li2O-Al2O3 melt is computationally investigated by applying a non-equilibrium thermodynamic model to understand the influence of varying processing conditions on crystallization kinetics. A strategy is illustrated that allows the effective utilization of thermodynamic information obtained by the CALPHAD approach and molecular dynamics-generated diffusion coefficients to simulate kinetic-dependent solidification. Model calculations revealed that melts with compositions close to γ-LiAlO2 remain comparatively unaffected by the external heat extraction strategies due to rapid internal kinetic processes. Kinetic limitations, especially diffusion, become significant for high cooling rates as the melt composition deviates from the stoichiometric compound.

Spectroscopic Investigation of the Interaction of Silicate Ions with Lead Carbonates Under Drinking Water Conditions.

The presence of lead has been identified as a critical health risk in drinking water systems serviced by Pb-bearing plumbing. Among several corrosion control strategies, the use of sodium silicates has attracted interest due to the advantages it offers compared to other approaches, such as phosphate dosage. However, the interaction of silicate ions with lead corrosion scales and other ubiquitous dissolved species such as Al ions in drinking water is not well understood. In this work, surface and bulk spectroscopic analysis of the solid scale is combined with quantitative analysis of the aqueous phase. A detailed spectroscopic probing of the transformations taking place on the solid phase enables us to develop a mechanistic framework for reports published in the last four years in the open literature, suggesting that silicates may not be an adequate corrosion control option in drinking water systems rich in solid lead carbonates. The spectroscopic data obtained demonstrate that in the presence of chlorine residual, silicates inhibit Pb(II) carbonates from oxidizing into less soluble Pb(IV) oxides thus, negatively impacting water quality. Furthermore, aluminum ions interact with silicates resulting in the formation of solid allophane phase over the lead scale surface, extending into the bulk. However, the formation of this new solid allophane phase does not protect against lead dissolution.

Influence of Additives on Crystallization of Calcium Phosphates from Prototypes of Blood Plasma

The paper presents the results of studies on the effect of additives on crystallization in solutions simulating the composition of human blood plasma. Synthesis from prototypes of human blood plasma in the presence of organic and inorganic additives was carried out, and it was found that the obtained solid phases consisted of octacalcium phosphate, B-type carbonate hydroxyapatite, and vitlocite. The effect of additives (magnesium ions, alanine, and glycine) on the crystallization of calcium phosphates was studied. It was found that the presence of additives in the model solution reduces the crystallite size and the fraction of carbonate hydroxyapatite in the solid phase. The bioactivity of synthetic samples was studied, and kinetic characteristics were established. A study of thermal transformations.

Frustrated Radical Pairs: From Fleeting Intermediates to Isolable Species.

We present the design and comprehensive investigation of stable para-substituted triarylamine-2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) radical ion pairs (RIPs) generated via single-electron transfer (SET). We quantified the degree of SET in both solution and solid phases, utilising a suite of spectroscopic techniques including IR, EPR, NMR, and single-crystal X-ray diffraction (SC-XRD). Our findings reveal that the extent of SET is significantly influenced by the nature of the substituents (MeO > tBu > Br) and the polarity of the solvent (MeCN > DCM > toluene). The radical ion pair [(pMeOPh)3N]•+[DDQ]•- was unambiguously identified using EPR and UV-vis spectroscopy, and its structure was confirmed by SC-XRD. Detailed analysis indicates an open-shell singlet ground state with a thermally accessible triplet state, as corroborated by EPR, magnetic susceptibility measurements, and DFT calculations. This study offers crucial insights into the mechanistic pathways of RIP formation and tuning both in solution and solid states, laying the groundwork for future exploration of their reactivity and potential applications.

Characteristics of Solid Mineral Phase Transitions During Sulfuric Acid Production from Gaseous-Sulphur-Reduced Gypsum

The acid co-production of cement is a prominent research focus for the large-scale, high-value utilization of phosphogypsum in the context of dual-carbon strategies. This paper builds on extensive research conducted by its authors on the co-production of sulphoaluminate cement clinker through acid production from gaseous-sulphur-reduced phosphogypsum. The solid mineral phase transformations occurring in the kiln during this process are systematically studied, and the effects of various calcination regimes (temperature, time, and atmosphere) on the evolution of clinker mineral phases are elucidated. This paper provides basic data support for the gas-sulfur-reduced phosphogypsum-acid cogeneration of sulfoaluminate cement clinker processes, and promotes the realization of the large-scale high-value utilization of phosphogypsum resources. The generation of the clinker mineral phase anhydrous calcium sulphoaluminate (C4A3S̅) begins at 1100 °C. Increasing the calcination temperature and extending the calcination time promote C4A3S̅ formation. However, when the calcination temperature exceeds 1350 °C, C4A3S̅ decomposes, leading to the formation of low-activity C2AS. In a CO atmosphere, the main mineral phases in the clinker transform into C2AS and 12CaO·7Al2O3, owing to the decomposition of CaSO4, which inhibits C4A3S̅ formation. At calcination temperatures exceeding 1300 °C, a significant amount of C2AS appears in the calcined material, and 12CaO·7Al2O3 begins to form.

Antibiotics in honey: a comprehensive review on occurrence and analytical methodologies.

Honey is a food of great nutritional importance and has always been used for human consumption. The production of honey and other beekeeping products depends on the proper functioning of this extremely important sector, as it has a direct impact on other sectors such as agriculture. The decline in bee colony numbers has been linked, among other factors, to bacterial diseases affecting bees, including American and European foulbrood, and Nosema spp. disease. In this matter, prophylactic or therapeutic use of veterinary drugs in apiculture is common but can lead to their accumulation in bees and in honey. Consumption of contaminated honey can have adverse effects such as allergic or hypersensitivity reactions, carcinogenicity, reproductive effects, and teratogenicity. Commission Regulation (EU) N ⍛ 37/2010 sets MRLs for antibiotics in various foods, but these limits are not set for api-products. The lack of harmonized rules has led some countries to set recommended concentrations and minimum performance limits. Nonetheless, to achieve this goal, development of accurate and precise analytical methodologies is crucial. In recent years, the analysis of antibiotics in honey has led to the development of methods in an extensive range of families, including aminoglycosides, amphenicols, lincosamides, macrolides, nitroimidazoles, quinolones, sulfonamides, tetracyclines and nitrofurans. This review work entails an in-depth exploration of occurrence studies, extraction methodologies, and analytical techniques for the determination of antibiotics in apiculture products. It was found that the most used extraction methods include solid-phase extraction, dispersed solid or liquid phase extraction and QuEChERS. Due to the complexity of the honey matrix, samples are often diluted or acidified using McIlvaine buffer, H 2O, MeOH, acidified ACN and TCA solution. This is usually followed by a purification step using SPE cartridges or PSA. Golden analytical methodologies include high-performance liquid chromatography coupled to a triple quadrupole mass spectrometer (MS/MS) with Orbitrap or Q-ToF detectors.

Synthesis of Tetra-ortho-Methoxylated Azobenzene Photoswitches via Sequential Catalytic C-H Activation and Methoxylation.

Functionalized tetra-ortho-methoxyazobenzenes have been prepared in a two-step approach based on palladium-catalyzed C-H ortho bromination of azobenzenes, followed by copper-catalyzed methoxylation. The method has shown a broad tolerance to different functional groups that could not be incorporated by previous strategies. With this two-step transition metal-catalyzed strategy, we achieved overall yields that range from good to excellent and enable the exploitation of these highly coveted photoswitches. The superior robustness of this scaffold for solid phase peptide synthesis (SPPS) applications when compared to its chlorinated counterpart has been demonstrated after extensive treatments with piperidine while bound to a RinkAmide ChemMatrix resin, showcasing their potential for use in the synthesis of red-light-operated peptides.