Solvent Research Articles

Exploring Mixed Hydrotropy Concept in HPTLC Densitometric Estimation of Telmisartan.

Analysis of the poorly water-soluble drugs most frequently carried out by using organic solvents like methanol, ethanol, chloroform, acetonitrile, and hexane. Most of them have toxic effects on humans as well as the natural ecosystem. The volatile nature of organic solvents is a major source of inaccuracy. So, the current study provides the best approach to replace organic solvents as hydrotropic solubilization techniques and developed a green, eco-friendly method to estimate telmisartan by highperformance thin-layer chromatography (HPTLC). Using silica gel coated (60 F254) TLC plates, chromatographic separation was achieved with a mobile phase 30% Sodium Benzoate (SB): 20% sodium acetate (SA): 0.5% citric acid (CA) (6:3:0.5 v/v/v). The retention factor for telmisartan was 0.55. Concentrations were linear in between 500 to 900 µg/mL with a regression coefficient was 0.9930. This approach was successfully validated as per the International Conference on Harmonization and it exhibits satisfactory results for all parameters. The developed approach is capable of being used to conduct routine evaluations of telmisartan in bulk and marketed formulation.

Towards portable kits for on-site colorimetric detection of aqueous hydrazine using piperidine-thiophene-barbituric acid push-pull probe.

Owing to the carcinogenicity and environmental risks as well as the wide industrial use of hydrazine, we report herein a colorimetric probe for its ratiometric detection in pure water. The developed probe possesses push-pull architecture with 2-(piperidyn-1-yl)thiophene as the donor, N,N'-dibutylbarbituric as the acceptor, and butadiene as the spacer. In contrast to weak solvatochromic behavior in organic solvents, the probe showed distinct optical photophysical properties in water resulting from the formation of nanoscopic aggregates. The probe underwent pronounced spectral changes upon the addition of hydrazine including an 11.5-fold decrease in absorbance and ~2.4-fold fluorescence quenching. The mechanistic investigation revealed the rapid formation of hydrazone upon the interaction of the probe with hydrazine via retro-Knoevenagel reaction as confirmed experimentally and corroborated with DFT calculations. The induced colorimetric and fluorometric changes were utilized in hydrazine sensing with excellent selectivity over other biologically relevant analytes with a detection limit of 0.76 µM in aqueous media. The practical utility of the probe was assessed in real-life natural water samples, while we have also developed a cost-effective portable kit for the on-site hydrazine detection both in the solution and vapor phases.

Optimizing the Formula of Polymeric-Based Aripiprazole Nanosuspension Using Response Surface Methodology for Intranasal Drug Delivery

This study aimed to optimize the formula of aripiprazole nanosuspension for intranasal drug delivery. Response Surface Methodology (RSM) was employed to determine the influence of independent variables, including drug concentration, polymer concentration, and the ratio of polymer combination, on the nanosuspension characteristics. The parameters under investigation were particle size (d mean), polydispersity index, and drug content. Fifteen formulas were prepared using the high-shear homogenization–ultrasonication method, and the Design Expert software was applied for optimum formula determination. The result showed significant effects of the independent variables on the nanosuspension characteristics, with particle sizes ranging from 143.6 – 334.6 nm, PDI values of 0.302 – 0.649, and drug content was 98.7 – 102.1 %. The predicted optimum formula had a drug concentration of 28 mg/mL in the organic solvent, polymer concentration of 1.5% (w/v), and HPMC to PVP ratio of 1.4 with desirability of 0.94. Additionally, it exhibited desirable characteristics, such as a particle size of 171.2  11.4 nm, a PDI value of 0.317  0.02, and a high drug content of 100.04  0.65%. In conclusion, the presented methodology appeared to be perfect for the optimization of the aripiprazole nanosuspension formula to ensure suitability for nose-to-brain drug delivery.

Investigation of the influence of ivermectin on potato plants in vitro

Aim. Investigation of the influence of ivermectin dissolved in different organic solvents (DMSO and ethanol) on morpho-physiological parameters of potato plants (Solanum lycopersicum) in vitro. Methods. Potato plants of cv. Vernisage were cultivated in vitro on MS medium in the presence of 10, 50 and 100 μg/ml of ivermectin dissolved in DMSO or ethanol, control plants – on MS medium without addition of any agents, and the plants grown on MS medium supplemented with 0.04, 0.2, 0.4 % of ethanol or DMSO were used as negative control. The influence of ivermectin, DMSO and ethanol was evaluated after 1 month of cultivation by the length of plant shoots, total leaf area and photosynthetic pigments content. Results. The growth-stimulating activity of ivermectin at concentration of 10 μg/ml and of the solvents at concentration of 0.04 % was identified, and also the phytotoxic influence of DMSO at concentrations 0.2 and 0.4 % alone or in the presence of ivermectin dissolved in it was shown in this study. Also, it was found that photosynthetic pigments content in the presence of ivermectin dissolved in ethanol, and in the presence of 0.04 % of ethanol was higher than in control. Conclusions. It has been established that the influence of ivermectin on morpho-physiological parameters of plants depends on the solvent in which it is dissolved for research purposes.

The preparation of melt electrospun fiber containing tandospirone for drug sustained release

AbstractElectrospun fibers membrane is considered an efficient drug carrier for transdermal drug delivery due to its breathability and high drug loading percentage, compared with coating film. However, pollution and safety risk caused by the use of organic solvents during the solution electrospinning process limit its industrialization and direct application in the biomedical field. Herein, a fiber membrane containing tandospirone was prepared using the melt electrospinning process and to be used for sustained drug release. The process of fiber preparation is an eco‐friendly and safe process due to the characteristics of solvent‐free. The in vitro drug release results showed that the fiber membranes containing tandospirone had slower initial drug release and higher end drug release compared with coating film containing tandospirone. The sustained‐release property can be attributed to the crystalline structure of fibers and the higher‐end drug release can be attributed to the spatial packing structures in the fiber membrane. The large pores generated by the stack structure of the large fiber in the fiber membrane leads to low gas resistance (10.7 Pa), which is much lower than that of the coating film (511.2 Pa). Overall, this study presents a green and safe preparation method of fiber membrane containing tandospirone, providing an effective and adjunctive treatments for mental disorders.Highlights The tandospirone‐loaded fiber patch was prepared using an eco‐friendly method. Burst release inhibition and higher final release of tandospirone in fibers. The fiber patch provided excellent breathability compared to coating patch. Fibers with higher crystallinity showed better controlled release.

Lipase-catalyzed synthesis of erythorbyl oleate and its characterization as a multifunctional emulsifier.

Erythorbyl oleate (EO), a novel emulsifier with multifunctional properties, was synthesized via lipase-catalyzed solvent-free esterification between erythorbic acid and oleic acid. The reaction produced EO of 30.75±1.65mM at 60h, monitored by high-performance liquid chromatography (HPLC) analysis. Purified EO was chemically identified as 6-O-oleoyl-erythorbic acid by HPLC-electrospray ionization/mass spectrometry (ESI-MS), 1H nuclear magnetic resonance (NMR), and 13C NMR analyses, and further investigations on its multifunctionalities were conducted. EO displayed antioxidant activity equivalent to erythorbic acid in 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities. Investigation of the antibacterial activity of EO against foodborne pathogens showed MICs of 0.27±0.09 and 0.40mM for Bacillus cereus ATCC 10876 and Staphylococcus aureus ATCC 12692, respectively. EO also displayed interfacial properties, lowering interfacial tension between medium-chain triglyceride oil and water to 3.40±0.04 mN/m with a critical micelle concentration of 2.54±0.03mM. Dynamic light scattering analyses of the emulsion stabilized by EO demonstrated a similar polydispersity index (0.15±0.00) to Tween 80-stabilized emulsion (0.28±0.01), with an average droplet size of 173.2±1.8nm. In addition, the EO-stabilized emulsion exhibited a negative surface charge (-56.83±4.30mV) in zeta potential measurements, indicating sufficient electrostatic repulsion between droplets. These results suggest that EO is a multifunctional emulsifier to simultaneously control oxidative rancidification and bacterial spoilage in emulsion-based foods. Practical Application: EO was synthesized via an enzymatic esterification reaction between erythorbic acid and oleic acid. The synthetic process excluded any use of organic solvent, diminishing potential health hazards or environmental pollution associated with chemical reactions. The interfacial properties of the resultant EO, along with excellent antioxidant and antibacterial activities, propose its potential application in emulsion-based foods. Simultaneous control of bacterial spoilage and oxidative rancidification by EO would fulfill the industrial needs for extending shelf life and enhancing consumer safety.

Synthesis and Redox Activity of Polyenaminones for Sustainable Energy Storage Applications

In the search for novel polymeric molecules that could be used as electroactive materials, seven novel polyenaminones were prepared in high yields by the transaminative polymerization of resorcinol-derived bis-enaminones with m- and p-phenylenediamine and with 2,5-diaminohydroquinone. The obtained polymers show very low solubility in organic solvents and absorb UV light and visible light at wavelengths below 500 nm. All the obtained polymeric products were tested for redox activity in a Li battery setup. The 2,5-diaminohydroquinone-derived compound showed the best redox activity, with a maximum capacity of 86 mAh/g and relatively good capacity retention, thus confirming the hydroquinone group as the primary redox-active group. Other potential redox-active groups, such as resorcinol and conjugated carbonyls, showed limited activity, while variations in the phenylene groups and the substitution of phenolic groups in the resorcinol residue did not impact the electrochemical activity of the polymers. Their electrochemical properties, together with their previously established chemical recyclability, make polyenaminones promising scaffolds for the development of materials for sustainable energy storage applications.

Utilizing synergy of MLG and MWCNT with optimized mixing protocol to improve the high temperature stability of SBS modified bitumen

High temperature instability is the biggest problem which limits the application of Styrene-Butadiene-Styrene (SBS) modified bitumen in flexible pavements. Addition of multi-layer graphene (MLG) nanomaterial improves the performance of SBS modified bitumen, but deteriorates its thermal stability. The binary additive comprising of MLG and multi-walled carbon nanotubes (MWCNT) can be a way to improve the thermal stability through their synergistic effects, however, mixing protocol needs to be optimized simultaneously. In this present study, MLG, MWCNT and their combination have been dispersed by two different organic solvent dissolution protocols, i.e., wet and dry to prepare the SBS-nano modified binders. Thermal stability analysis and rheological characterization (small & large amplitude oscillatory shear) have been used to optimize the method and to compare the effect of sole and binary additive. Advanced tools such as Raman spectroscopy and Field emission scanning electron microscopy have been used to understand the underlying science at micro-molecular level. The synergistic effects of combined additives are prominently visible only in dry organic dissolution method and with this method, the combination of MLG-MWCNT (0.1phr-1phr) significantly eliminates the thermal instability of SBS modified binder by upto 96 %. This SBS-nano modified bitumen may serve as futuristic binder for the black top pavements.

Entrapment of Amphipathic Drugs in Core-Shell Polymeric Nanoparticles under Batch Conditions─The Role of Control and Solubility Parameters.

The amphipathic bioactive compounds curcumin, resveratrol, and mitomycin C, which have similar solubility parameter component distributions, have been studied for encapsulation under batch conditions into core-shell nanocarriers composed of external hydrophobically functionalized polyelectrolytes and an inner matrix of polyesters or polyester blends: poly(l-lactide), poly(lactide-co-glycolide), and/or poly(ethylene succinate). Our contribution comprises determining the influence of process parameters on the properties and quality of the final products, namely core-shell nanoparticles loaded with appropriate drugs, according to process analysis technologymanagement. The crucial roles of the organic phase dosing rates and process temperatures were carefully investigated. Moreover, a technically feasible method of removing organic solvents from aqueous dispersions─stripping with inert gas─was employed and evaluated via FT-IR studies. The experiments were supported by the calculation and analysis of solubility parameters (δ) and dispersion (δd), polar (δp), and hydrogen bond (δh) components utilizing HSPiP software. The payload locus and sample morphology were studied via atomic force microscopy and X-ray photoelectron spectroscopy analyses with Ar+ sputtering. It was demonstrated that dosing rates of organic phases not exceeding ca. 0.5 mL/min per 1 L of aqueous dispersion of hydrophobically functionalized polyelectrolytes made it possible to obtain core-shell nanoparticles of ca. 100-150 nm with a very narrow polydispersity (PdI < 0.2). The locus of amphipathic payloads in nanocarriers, mostly within the core polymeric structure, was in good agreement with the results of solubility parameter component studies: water-insoluble polyesters with both polar and nonpolar interactions between chains serve as good host materials for amphipathic drugs.

One-pot, Solvent Free Synthesis of2,5-Furandicarboxylic Acid from Deep Eutectic Mixtures of Sugars as Mediated by Bifunctional Catalyst.

Currently one-pot conversion of sugars to 2,5-furandicarboxylic acid (FDCA) is of significant interest due to the attainability of sugars as a feedstock and the enormous potential of FDCA as a bioplastic monomer. However, it remains challenging to construct efficient catalysts for this process. In this study, Co3O4species were anchored to a sulfonated covalent organic framework thus affording a bifunctional catalyst (Co3O4@COF-SO3H). The sulfonic acid sites dehydrate sugars to 5-hydroxymethylfurfural (HMF), which is next oxidized to FDCA as catalyzed by the Co3O4species. Such a process was applied in the conversion of various binary and ternary deep eutectic mixtures involving choline chloride and sugars without additional solvent. The maximum FDCA yield of 84% was obtained using glucose-fructose eutectic mixture as the substrates. Moreover, the catalyst was recyclable and stable under the applied reaction conditions. Our process eliminates the employment of organic solvents and expensive noble metal catalysts, resulting in green and economic biomass conversions.

Protonated polyethyleneimine enables synchronous crosslinking of polyimide nanofiltration membranes for dye desalination

Dye recovery and desalination are of great significance in the treatment of printing and dyeing wastewater. Nanofiltration (NF) has been proved an effective method for dye desalination. As organic solvents are usually coexisted, there is a great demand for organic solvent nanofiltration (OSN) membranes. Compared to thin film composite (TFC) membranes prepared by interfacial polymerized (IP), integrally skinned asymmetric (ISA) membranes with relatively thicker selective layer may present better separation stability in harsh solvent and cleaning reagent. In this work, polyethyleneimine-b-polyethersulfone (PEI-PES) is synthesized and added to PI solution directly, the crosslinking reaction proceeds along with phase conversion process. The PEI chains endow the membrane with good hydrophilicity and high positive charge. PEI-PES/PI membranes show stable permeability in organic solvents such as N, N-dimethylformamide (DMF), ethanol (EtOH) and toluene, etc. The rejections of dyes such as Congo Red (CR), Janus Green B, and Sunset Yellow are over 95 % in EtOH, while the rejections of salts like MgSO4 and Na2SO4 are around 20 %. After 200 h separation test, the rejection for CR remains around 92 % in DMF and 96 % in EtOH with a stable flux. The simple and cost-effective preparation process can accelerate the progress of the positively charged OSN membranes.

Profiling 32 alkaloid compounds from Macleaya cordata by UPLC-DAD–QTOF-MS/ms

Macleaya cordata is a traditional herb medicine with alkaloids as the main bioactive substance. To identify alkaloid compounds from M. cordata, its crude extract was obtained with 0.2 mol/L hydrochloric acid, and alkaloid compounds in the demineralised extract by organic solvents from crude extract were qualitatively and quantitatively analysed by UPLC-DAD–QTOF-MS/MS. Through systematic analysis of retention times, mass spectrometry data, and diagnostic fragmentation pathways and rules, 32 alkaloids were rapidly unambiguously identified or tentatively deduced by comparison with standard MS spectra or literature data. Among them, 16 minor ­alkaloid compounds including nandazurine, hydroxychelidonine, capauridine, (-)-dicentrine, leptopine, adlumidine, takatonine, (2, 3)-trans-N-(p-hydroxyphenethyl)ferulamide, 9-ethoxyaristololactam, thalicminine, cassythidine, acetylisocorynoline, oxynitidine, crinasiatine, zanthoxyline, and 7,9-dimethoxy-2,3-methylendioxybenzophenanthridine were found in M. cordata for the first time. The abundant alkaloids might be responsible for the bioactivity of M. cordata, which laid a foundation for the study of quality control, livestock, and clinical applications of M. cordata.

Investigating Metastable Gelation Behavior of Coumarin‐Derived β‐Enaminone‐Boron Difluoride Complexes

Gelation behavior was unearthed while investigating the photophysical properties of β‐enaminones and their difluoroboron complexes. To perform a systematic investigation, a library of β‐enaminone’s difluoroboron complexes was prepared to examine their gelation behavior in organic solvents. Among the prepared compounds, the N‐butyl amine‐substituted β‐enamino diketone was found to exhibit metastable gelation properties in a mixed solvent system (methylene chloride and hexane). Our studies suggest that the presence of N‐butylamine moiety along with N,N‐dimethylamino substituent at difluoroboron enaminones is indispensable in imparting the metastable gelation behavior.

Investigating the Use of Natural Hydrophobic Deep Eutectic Solvents for Extracting Carotenoids from Food and Food By-products

Abstract In today’s food industry, the demand for sustainable methodologies in producing health-promoting natural products is rising. Traditional extraction techniques are increasingly deemed unreliable due to environmental concerns. To address these challenges, the scientific community has developed Green Chemistry , a specialized branch that aims to minimize or eliminate hazardous processes and substances in industrial applications. One promising and eco-friendly alternative emerging from Green Chemistry is the use of NaDESs which are prepared with natural components, generally recognized as safe (GRAS), and offer an environmentally benign option for various industrial processes. They are characterized by their biodegradability, low toxicity, and ability to be tailored for specific applications, making them an ideal choice for green extraction methods. In this context, NaHDESs have shown significant potential as extracting media for bioactive compounds, particularly carotenoids, from food and food by-products. Carotenoids, known for their antioxidant properties and health benefits, are highly sought after in the food and nutraceutical industries. Traditional extraction methods often rely on organic solvents, which pose environmental and health risks. In contrast, NaHDESs offer a safer and more sustainable alternative. This study explores the definition, properties, and applications of NaHDESs, with a particular focus on their use in extracting carotenoids. By examining various food and vegetable by-products, the research aims to evaluate the solvent’s efficiency and effectiveness in this application. The findings could pave the way for eco-friendly extraction techniques in the food industry, aligning with the principles of Green Chemistry and addressing the growing demand for natural and health-promoting products. Information © The Author 2024

Hass Avocado (Persea americana Mill) Peel Extract Reveals Antimicrobial and Antioxidant Properties against Verticillium theobromae, Colletotrichum musae, and Aspergillus niger Pathogens Affecting Musa acuminata Colla Species, in Ecuador

The utilization of agroindustrial residues, such as avocado peel, as a source of bioactive compounds with antioxidant properties has garnered significant attention. In this study, we investigated the antioxidant potential using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity) methods, along with the antimicrobial activity of phenolic compounds extracted from Hass avocado peel. These soluble polyphenols were quantified and identified using high-performance liquid chromatography (HPLC). The research focused on their effects against three fungal pathogens, Verticillium theobromae, Colletotrichum musae, and Aspergillus niger, which significantly impact banana crops, an essential agricultural commodity in Ecuador. The results have revealed that the application of 80% ethanol as an organic solvent led to increased soluble polyphenol content compared to 96% ethanol. Extraction time significantly influenced the phenolic content, with the highest values obtained at 90 min. Interestingly, despite substantial mycelial growth observed across all extract concentrations, the antifungal effect varied among the pathogens. Specifically, V. theobromae exhibited the highest sensitivity, while C. musae and A. niger were less affected. These results underscore the importance of considering both antioxidant and antimicrobial properties when evaluating natural extracts for potential applications in plant disease management.

Thin film nanocomposite membrane ornamented with Z-scheme heterojunction carbon dot/NiFe–LDH for removal of organic contaminants from industrial wastewater

Removal of organics from wastewater is a tedious process and industries are looking for a facile, energy efficient strategy of wastewater treatment for producing clean water and recycling. Membrane technology is one of the efficient processes for wastewater treatment due to its energy efficient nature, simple operation and excellent performance. But, proneness of membrane fouling often limits its path to triumph. In this work, we have designed a ‘carbon dot/NiFe-layered double hydroxide (CD/NiFe–LDH)’ nanocomposite via in situ approach, which is coated on a poly(ethylene terephthalate) (PET) and cellulose based superhydrophillic membrane. The membrane is found to have excellent separation efficiency. The photocatalytic activity of CD/NiFe–LDH shows high oxidative degradation of the accumulated organics contaminants on the membrane surface providing self-cleaning ability and hence enhances the membrane’s lifetime. The membrane exhibits stable performance for 30 days continuous operation under UV-A light. The membrane flux is found to be ∼42 Lm−2 h−1 and 48 Lm−2 h−1 for crude oil–water emulsion and phenol respectively while rejection around ≥99 % is obtained for the both. The flux recovery ratio (FRR) of the post photo irradiated membrane is found to be 88.07 %. The membrane also shows organic solvent resistance property and prevents bacterial pathogens in wastewater.

Cross-Linked Metathesis Polynorbornenes Based on Nadimides Bearing Hydrocarbon Substituents: Synthesis and Physicochemical Properties.

Metathesis homo- and copolymerization of bifunctional monomers bearing two norbornene moieties was studied. The monomers were synthesized from cis-5-norbornene-exo-2,3-dicarboxylic anhydride and various diamines (hexamethylenediamine, decamethylenediamine, 1R,3S-isophoronediamine). The metathesis homopolymerization of these bis(nadimides) in the presence of the second-generation Grubbs catalyst afforded glassy cross-linked polymers in more than 90% yields. The metathesis copolymerization of the bis(nadimides) and a monofunctional norbornene derivative containing the β-pinene fragment also resulted in insoluble cross-linked polymers in nearly quantitative yields. The structures and purity of the synthesized polymers were confirmed via IR spectroscopy and CP/MAS NMR spectroscopy. Conditions for the fabrication of mechanically strong solution-cast thin films based on copolymers synthesized from the comonomers mentioned above were determined by varying the content of the cross-linking agent. It was shown that the films made in this way are stable in a range of organic solvents and could be useful as semipermeable or membrane materials for use in liquid organic media. The permeability of the polymer films in question to 1-phenylethanol and mandelic acid was studied. The results obtained are discussed along with the data from the DSC, TGA, and powder X-ray diffraction studies of the properties of the synthesized metathesis homo- and copolymers.

Simultaneous rare earth sulfate transformation and carbon dioxide mineralization

The wet metallurgical process route for recovering rare earth elements usually uses sulfuric acid. To obtain marketable individual rare earth products, converting rare earth sulfates to chlorides is essential. Conventional chemical precipitation and solvent extraction methods result in significant amounts of ammonia wastewater and greenhouse gas emissions. Therefore, we propose a novel process that integrates CO2 mineralization with rare earth sulfates transformation. By utilizing a base-catalyzed mechanism with trioctylamine (TOA), CO2 is effectively employed for selective precipitation of more than 95 % of rare earths from magnesium and calcium under optimized conditions. Subsequently, dissolution in hydrochloric acid allows for enrichment of the concentration of rare earths up to 188.3 g/L. The reaction mechanism is examined through Visual MINTEQ simulations and various analytical techniques. This process not only offers a sustainable approach to rare earth sulfates transformation but also contributes to carbon capture, utilization, and sequestration efforts.

Development of a superheated water chromatography method for the sustainable determination of preservatives in foods and cosmetics

The present research focused on the use of high temperatures to achieve fast separations in Liquid Chromatography (LC) and minimize the consumption of organic solvents. Particularly, superheated water was employed, by exploiting the decrease in dielectric constant of water when increasing the temperature. To realize this kind of application, the availability of LC columns resistant at high temperature is mandatory. Recently, porous graphitic carbon (PGC) columns have been proposed as stationary phases resistant up to 250 °C. Hardware modifications were also necessary to guarantee the efficient heating of the mobile phase prior of entering the column, as well as its rapid cooling before detection by photodiode array (PDA). Specifically, an LC system was interfaced to a GC oven, which hosted the LC column; to achieve a fast and efficient heating of the eluent coming from the autosampler prior to enter into the column, a pre-heating tube was interposed between the autosampler outlet and the column inlet. Instead, a cooling loop was connected between the column outlet and the PDA cell. A mixture of 1-nitroalkanes was used to evaluate the performance of the system in terms of dead volumes, band broadening and peak shape, as well as chromatographic efficiency and resolution. The use of higher temperatures allowed to perform analyses at higher flow rates in reduced analysis time and was also in terms of peak bandwidth resulting to increased efficiency for the most retained compound. Moreover, van't Hoff plots were obtained at different temperature, confirming that the most retained analyte greatly benefited of the temperature increase.The system was applied to the analysis of parabens in cosmetic and food products. The method combined eco-sustainable sample preparation with high-temperature LC separation on a PGC column and was fully validated in terms of linearity, precision, accuracy and detection and quantification limits. The developed method was critically evaluated by comparing the output of different metric tools implemented in the last decade for the quantitative assessment of the greenness.

Natural Rubber Films Reinforced with Cellulose and Chitosan Prepared by Latex Aqueous Microdispersion.

In this paper, green composite films comprising natural rubber (NR), cellulose (CE), and chitosan (CS) were successfully fabricated through a simple, facile, cost-effective method in order to improve mechanical, chemical, and antimicrobial properties of NR composite films. Chitosan with a low molecular weight of 30,000-50,000 g/mol (CS-L) and a medium molecular weight of 300,000-500,000 g/mol (CS-M) was used for the fabrication. The composite films were prepared via a latex aqueous microdispersion method with different weight ratios of NR:CE:CS-L/CS-M. Fourier transform infrared spectroscopy (FTIR) results demonstrated strong interactions of hydrogen bonds between CE and CS-L/CS-M in the composite films. The tensile strength and the modulus of the composite films in dried form were found to significantly increase with the reinforcement of CE and CS-L/CS-M. The maximum tensile strength (13.8 MPa) and Young's modulus (12.7 MPa) were obtained from the composite films reinforced with CE at 10 wt.% and CS-L at 10 wt.%. The high elongation of 500-526% was obtained from the composite films reinforced with CE at 10 wt.% and CS (CS-L or CS-M) at 5.0 wt.%. The modification could also significantly promote antimicrobial activities and chemical resistance against non-polar solvents in the composite films. The NR composite films have potential uses as flexible films for sustainable green packaging.