Organic Solvent-free Research Articles

Improved bioavailability of curcumin in liposomes prepared using a pH-driven, organic solvent-free, easily scalable process

pH-driven method, an organic solvent-free and easily scale-upable method, was firstly utilized to prepared curcumin-loaded liposomes.

Organic Solvent-Free, One-Step Engineering of Graphene-Based Magnetic-Responsive Hybrids Using Design of Experiment-Driven Mechanochemistry.

In this study, we propose an organic solvent-free, one-step mechanochemistry approach to engineer water-dispersible graphene oxide/superparamagnetic iron oxide (GO/SPIOs) hybrids, for biomedical applications. Although mechanochemistry has been proposed in the graphene field for applications such as drug loading, exfoliation or polymer-composite formation, this is the first study to report mechanochemistry for preparation of GO/SPIOs hybrids. The statistical design of experiment (DoE) was employed to control the process parameters. DoE has been used to control formulation processes of other types of nanomaterials. The implementation of DoE for controlling the formulation processes of graphene-based nanomaterials is, however, novel. DoE approach could be of advantage as one can tailor GO-based hybrids of predicted yields and compositions. Hybrids were characterized by TEM, AFM FT-IR, Raman spectroscopy, and TGA. The dose–response magnetic resonance (MR) properties were confirmed by MR imaging of phantoms. The biocompatibility of the hybrids with A549 and J774 cell lines was confirmed by the modified LDH assay.

Aqueous microwave-assisted solid-phase peptide synthesis using Fmoc strategy. III: Racemization studies and water-based synthesis of histidine-containing peptides

In this study, we describe the first aqueous microwave-assisted synthesis of histidine-containing peptides in high purity and with low racemization. We have previously shown the effectiveness of our synthesis methodology for peptides including difficult sequences using water-dispersible 9-fluorenylmethoxycarbonyl-amino acid nanoparticles. It is an organic solvent-free, environmentally friendly method for chemical peptide synthesis. Here, we studied the racemization of histidine during an aqueous-based coupling reaction with microwave irradiation. Under our microwave-assisted protocol using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, the coupling reaction can be efficiently performed with low levels of racemization of histidine. Application of this water-based microwave-assisted protocol with water-dispersible 9-fluorenylmethoxycarbonyl-amino acid nanoparticles led to the successful synthesis of the histidine-containing hexapeptide neuropeptide W-30 (10-15), Tyr-His-Thr-Val-Gly-Arg-NH₂, in high yield and with greatly reduced histidine racemization.

Novel Organic Solvent Free Micro-/Nano-fibrillar, Nanoporous Scaffolds for Tissue Engineering

Novel organic solvent free micro-/nano-fibrillar composite scaffolds have been manufactured using poly(L-lactide) and glycol-modified poly(ethylene terephthalate) to evaluate cell growth potential on the nanoporous networks. The authors describe a method for producing nanoporous scaffolds from polymer blends and highlights some limitations and inaccuracies when measuring mechanical properties of fibrillar porous structures. It illustrates the importance of determining the actual cross-sectional surface area of the load resisting fibers rather than using the simple geometrical area if properties are to be determined accurately. Cellular-biocompatible testing with a mouse pre-osteoblastic (early bone-forming cells) cell line shows promise, with a live monolayer of cells present on the biomaterial after 7–10 days of culture. In addition, scaffolds have also been manufactured by using the traditional electrospinning method and their cyto-biocompatibility compared to the micro-/nano-fibrillar composite scaffolds, employing cell attachment and morphology studies. Some scaffold manufacturing issues have also been identified and discussed in relation to improved cell growth.

An automated solid-phase microextraction method based on magnetic molecularly imprinted polymer as fiber coating for detection of trace estrogens in milk powder

A new automated solid-phase micro extraction (SPME) sampling method was developed for quantitative enrichment of estrogens (ES) from milk powder, using magnetic molecularly imprinted polymer (MMIP) as fiber coating. The method (MMIP-SPME) was built with several electromagnetic stainless steel fibers, placed in parallel for simultaneously extraction. The MMIP was synthesized using core–shell Fe3O4@SiO2 nanoparticles (NPs) as magnetic support. Estradiol (E2) was employed as the template molecule, acrylamide (AA) as functional monomer, and ethylene glycol dimethacrylate (EGDMA) as cross-linker. MMIP can be easily absorbed or desorbed from fibers when the current is turned on or off, creating magnetism. Compared to traditional MIP-SPME, the prepared procedure of MMIP-SPME is time-saving and organic solvent-free. The proposed device significantly improved the efficiency of separation and enrichment of estrogens from complex matrices thereby and facilitating the pretreatment steps by electromagnetically controlled extraction fibers to achieve full automation. Several experimental parameters were studied, including extraction and desorption kinetics, solution pH, desorption solution, ratio, and shuttle rate. The newly developed MMIP-SPME showed good sensitivity and high binding capacity, fast adsorption kinetics and desorption kinetics for estrone (E1), estradiol (E2), estriol (E3) and diethylstilbestrol (DES) under optimized conditions. The detection limits for the four estrogens were 1.5–5.5ngg−1 with excellent reproducibility (RSD values less than 7.1%) when milk powder samples spiked with analytes at 20, 100 and 250ngg−1 were studied.

Aqueous Microwave-Assisted Solid-Phase Peptide Synthesis Using Fmoc Strategy. II. Racemization Studies and Water Based Synthesis of Cysteine- Containing Peptides

We have developed a microwave (MW)-assisted peptide synthesis using Fmoc-amino acid nanoparticles in water previously. It is an organic solvent-free, environmentally friendly method for peptide synthesis. In this study, we have investigated the racemization of cysteine during an aqueous based coupling reaction with MW irradiation. Under our MW-assisted protocol using WSCI and DMTMM, the coupling reaction can be performed with low levels of racemization of cysteine. We also demonstrated the synthesis of the nonapeptide oxytocin analogue, Cys(Acm)-Tyr-Ile-Gln-Asn- Cys(Acm)-Pro-Leu-Gly-NH2 using our water based MW-assisted protocol with Fmoc-amino acid nanoparticles.

Aqueous Microwave-Assisted Solid-Phase Synthesis Using Boc-Amino Acid Nanoparticles

We have previously developed water-based microwave (MW)-assisted peptide synthesis using Fmoc-amino acid nanopaticles. It is an organic solvent-free, environmentally friendly method for peptide synthesis. Here we describe water-based MW-assisted solid-phase synthesis using Boc-amino acid nanoparticles. The microwave irradiation allowed rapid solid-phase reaction of nanoparticle reactants on the resin in water. We also demonstrated the syntheses of Leu-enkephalin, Tyr-Gly-Gly-Phe-Leu-OH, and difficult sequence model peptide, Val-Ala-Val-Ala-Gly-OH, using our water-based MW-assisted protocol with Boc-amino acid nanoparticles.

Simplified and Small-Scale Technique for Quantifying Ractopamine in Beef under Organic Solvent-Free Conditions

This paper described an organic solvent-free, simple, and small scale method of sample preparation followed by high-performance liquid chromatography (HPLC) coupled photo-diode array (PDA) detector for quantifying ractopamine (RP) in beef. The HPLC-PDA was performed on an Inertsil ® HILIC, hydrophilic interaction chromatographic mode, column with an isocratic aqueous mobile phase. An analyte was extracted from the sample using a handheld ultrasonic homogenizer with trichloroacetic acid solution and purified by MonoSpin ® SCX, a centrifugal monolithic silica spin mini-columns, and quantified within 25 min. The proposed method obtained average recoveries for the analyte in the range of 95.2 - 103.1% with relative standard deviations ≤ 2.8%. The quantitation limit was 10 ng g -1 in the flank and liver.

Organic Solvent-Free and Simple Method for Determining Cyromazine and its Metabolite, Melamine, in Cow’s Milk

This paper described an organic solvent-free, rapid, simple, and space-saving method of sample preparation followed by HPLC coupled photo-diode array (PDA) detector for simultaneous quantification of cyromazine (CYR) and its decycropropylated metabolite, melamine (MEL), in milk. The HPLC-PDA was performed on an InertsilR HILIC column with an isocratic aqueous mobile phase. Analytes were extracted from the sample using water, and purified by MonoSpinR-C18, a centrifugal monolithic silica spin mini-columns, and quantified within 20 min. The method, performed under 100% aqueous conditions, obtained average recoveries for CYR and MEL in the range of 93.2 . 99.1% with relative standard deviations . 2.8%. The quantitation limits were 8.5 ng/mL for CYR and 10 ng/mL for MEL, respectively. No organic solvents were used at any stage of the analysis.

Organic Solvent-Free and Simple Method for Determining Cyromazine and Its Metabolite, Melamine, in Cow’s Milk

This paper described an organic solvent-free, rapid, simple, and space-saving method of sample preparation followed by HPLC coupled photo-diode array (PDA) detector for simultaneous quantification of cyromazine (CYR) and its decy-cropropylated metabolite, melamine (MEL), in milk. The HPLC-PDA was performed on an Inertsil? HILIC column with an isocratic aqueous mobile phase. Analytes were extracted from the sample using water, and purified by Mono-Spin?-C18, a centrifugal monolithic silica spin mini-columns, and quantified within 20 min. The method, performed under 100% aqueous conditions, obtained average recoveries for CYR and MEL in the range of 93.2% - 99.1% with relative standard deviations ≤ 2.8%. The quantitation limits were 8.5 ng/mL for CYR and 10 ng/mL for MEL, respectively. No organic solvents were used at any stage of the analysis.

Flame Atomic Absorption Determination of Trace Amounts of Cadmium After Preconcentration Using a Thiol-Containing Task-Specific Ionic Liquid

Dispersive liquid-liquid microextraction (DLLME) based on a task-specific ionic liquid (TSIL) was developed for the extraction and preconcentration of trace amounts of cadmium from aqueous samples, followed by flame atomic absorption spectrometry (FAAS) determination. In the proposed approach, cadmium ions are extracted from aqueous samples using small volumes of trioctylmethylammonium thiosalicylate (TOMATS) dissolved in acetone. TOMATS is a thiol-containing TSIL that can form metal thiolate complexes due to the chelating effect of the ortho-positioned carboxylate group relative to the thiol functionality. The main parameters affecting the performance of DLLME based on TSIL, such as pH, amount of TOMATS, extraction time, injection volume, salt addition, and centrifugation time, were optimized. Under optimum conditions, an LOD of 1.16 ng/mL and a good RSD of 1.8% at 60.0 ng/mL were obtained (n=7). The proposed method was applied to tap water, wastewater, well water, and milk samples. The results showed that DLLME based on TSIL combined with FAAS is a rapid, simple, sensitive, selective, low cost, volatile organic solvent-free, and efficient analytical method for the separation and determination of trace amounts of cadmium ions.

Trace determination of hexabromocyclododecane diastereomers in water samples with temperature controlled ionic liquid dispersive liquid phase microextraction

Abstract A novel temperature controlled ionic liquid dispersive liquid phase microextraction (TCIL-DLPME) coupled with rapid resolution liquid chromatography–electrospray tandem mass spectrometry (RRLC–ESI-MS–MS) has been developed for the enrichment and determination of three hexabromocyclododecane diastereomers (HBCDs) in water samples. Green solvent ionic liquid (IL) was used as extraction solvent instead of toxic organic solvents. This technique also avoided the usage of dispersive solvent. Some important parameters that might affect the extraction efficiency were optimized. Under the optimum conditions, good linear relationship, sensitivity and reproducibility were obtained. All the limits of detection for the three diastereomers were 0.1 ng/mL. The linear range was obtained in the range of 1–100 ng/mL for the total amount of three HBCD diastereomers. It was satisfactory to analyze real environmental water samples with the recoveries ranging from 77.2% to 99.3%. The main advantage of the method is toxic organic solvent-free.

ChemInform Abstract: Remarkable Influence of Substituent in Ionic Liquid in Control of Reaction: Simple, Efficient and Hazardous Organic Solvent Free Procedure for the Synthesis of 2‐Aryl Benzimidazoles Promoted by Ionic Liquid, [pmim]BF4.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Organic Solvent–Free Direct Asymmetric Aldol Reactions Catalyzed by a Siloxy Serine Organocatalyst in Brine

A siloxy serine organocatalyst has been developed to catalyze direct asymmetric aldol reactions in aqueous saline media. The asymmetric aldol reactions between a selection of aromatic aldehydes and cyclohexanone afforded the products in good yields and enantioselectivities (up to 92% ee).

Ionic liquid based dispersive liquid–liquid microextraction of aromatic amines in water samples

In this work, a new microextraction method termed ionic liquid based dispersive liquid–liquid microextraction (IL-DLLME) was demonstrated for the extraction of 2-methylaniline, 4-chloroaniline, 1-naphthylamine and 4-aminobiphenyl in aqueous matrices. After extraction the ionic liquid (IL) phase was injected directly into the high performance liquid chromatography (HPLC) system for determination. Some parameters that might affect the extraction efficiency were optimized. Under the optimum conditions, good linear relationship, sensitivity and reproducibility were obtained. The limits of detection (LOD, S/N = 3) for the four analytes were in the range of 0.45–2.6 μg L −1. The relative standard deviations (R.S.D., n = 6) were in the range of 6.2–9.8%. This method was applied for the analysis of the real water samples. The recoveries ranged from 93.4 to 106.4%. The main advantages of the method are high speed, high recovery, good repeatability and volatile organic solvent-free.

Organic Solvent-Free, Enantio- and Diastereoselective, Direct Mannich Reaction in the Presence of Water

An organocatalyst-mediated, asymmetric Mannich reaction in the presence of water without using organic solvents has been developed. A highly reactive siloxytetrazole hybrid catalyst has been developed for the reaction of dimethoxyacetaldehyde, while the sodium salt of siloxyproline is an effective catalyst of alpha-imino glyoxylate. Excellent enantioselectivity can be realized, and the usage of organic solvents can be reduced compared to the conventional reactions in organic solvents.

Catalyst-free synthesis of polyorganosiloxanes by high temperature & pressure water

A catalyst-free silicone synthetic process that uses high temperature and pressure water for the hydrolysis and subsequent polycondensation of alkoxysilanes is demonstrated. Polyorganosiloxanes with various structural units including RSiO 3/2 (R: methyl and phenyl), Me 2SiO 2/2, and SiO 4/2 were synthesized without organic solvent at temperatures between 200 and 300 °C. The driving force of the present catalyst-free reaction seems to be both high Kw of subcritical water and high reaction temperature. The synthesis depended on the pressure in a reactor because equilibrium is present between the polycondensation of phenyltrimethoxysilane yielding poly(phenylsilsesquioxane) (PPSQ) and depolymerization of PPSQ. The molecular weight of PPSQ decreased as the pressure increases above the pressure threshold ranging between approximately 3 and 7 MPa. It is notable that the molecular weight of PPSQ increased by employing a modified reaction system where non-heated narrow tubing was connected with the heated reactor. Advantageous features of this new process include (1) high product yield within quite shorter process time, (2) easiness of the product isolation, and (3) no contamination of volatile organic compounds in the product due to the organic solvent-free in nature. These may lead to developing an environmentally friendly polyorganosiloxanes manufacturing process.

Ionic Liquid–Promoted Stereoselective Synthesis of (Z)‐Vinyl Bromides by [bmIm]OH under Organic Solvent–Free Conditions: A Green Approach

A simple and easily accessible ionic liquid, 1‐butyl‐3‐methylimidazolium hydroxide ([bmIm]OH), has been demonstrated as an efficient promoter and reaction medium for the highly stereoselective synthesis of (Z)‐vinyl bromides by the debrominative decraboxylation of dibrominated α,β‐unsaturated carboxylic acids in high yields. The reaction does not require either a conventional base or an organic solvent.

Catalysis by Ionic Liquids: Cyclopropyl Carbinyl Rearrangements Catalyzed by [pmim]Br under Organic Solvent Free Conditions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Synthesis of Polyunsaturated Fatty Acid L-Menthyl Esters through Lipase-Catalyzed Esterification in an Organic Solvent-Free System

Synthesis of L-menthyl eicosapentaenoate was achieved through lipase-catalyzed esterification of eicosapentaenoic acid (EPA) with L-menthol in an organic solvent-free system. A suitable enzyme was a lipase from Candida rugosa (Lipase-AY, Amano Enzyme Inc., Aichi) when L-menthol was esterified at 30°C in a mixture of L-menthol/EPA (1.2/1, mol/mol), 20 wt% water and 1600 U/g-mixture of lipase. The reaction reached equilibrium after 3 d at ca. 75% esterification. L-Menthyl γ-linolenate and arachidonate could also be synthesized under the same conditions as those in synthesis of L-menthyl eicosapentaenoate, although the degrees of esterification after 4 d were 54 and 41%, respectively. Synthesis of L-menthyl eicosapentaenoate greatly depended on the water content, and reaction rate significantly decreased in the presence of < 20% of water.