Biocompatible nutmeg oil-loaded nanoemulsion as phyto-repellent

Plant essential oils are widely used in perfumes and insect repellent products. However, due to the high volatility of the constituents in essential oils, their efficacy as a repellent product is less effective than that of synthetic compounds. Using a nanoemulsion as a carrier is one way to overcome this disadvantage of essential oils. Nutmeg oil-loaded nanoemulsion (NT) was prepared using a high speed homogenizer and sonicator with varying amounts of surfactant, glycerol, and distilled water. Using a phase diagram, different formulations were tested for their droplet size and insect repellent activity. The nanoemulsion containing 6.25% surfactant and 91.25% glycerol (NT 6) had the highest percentage of protection (87.81%) in terms of repellent activity among the formulations tested for the 8 h duration of the experiment. The droplet size of NT 6 was 217.4 nm, and its polydispersity index (PDI) was 0.248. The zeta potential value was -44.2 mV, and the viscosity was 2.49 Pa.s at pH 5.6. The in vitro release profile was 71.5%. When the cytotoxicity of NT 6 at 400 μg/mL was tested using the MTS assay, cell viability was 97.38%. Physical appearance and stability of the nanoemulsion improved with the addition of glycerol as a co-solvent. In summary, a nutmeg oil-loaded nanoemulsion was successfully formulated and its controlled release of the essential oil showed mosquito repellent activity, thus eliminating the disadvantages of essential oils

Synthesis and characterization of cyclodextrin functionalized ionic liquid polymer for the extraction of phenols / Muggundha Raoov a/l Ramachandran

β-Cyclodextrin functionalized ionic liquid polymer (βCD-BIMOTs-TDI) was first synthesized by functionalized β-cyclodextrin (CD) with 1-benzylimidazole (BIM) to form monofunctionalized CD (βCD-BIMOTs), and was further polymerized using toluene diisocyanate (TDI) as a linker to form insoluble βCD-BIMOTs-TDI. The βCDBIMOTs- TDI was characterized using various tools and the results obtained were compared with those derived from the native β-cyclodextrin polymer (βCD-TDI). The scanning electron microscope (SEM) results showed that the presence of ionic liquid (IL) increased the pore size, while the thermo gravimetric analysis (TGA) results showed that the presence of IL increased the stability of the βCD-BIMOTs-TDI. Meanwhile, Brunauer-Emmett-Teller (BET) result showed that βCD-BIMOTs-TDI had 1.254 m2/g surface area, and the Barret-Joyner-Halenda (BJH) pore size distribution result revealed that the polymer exhibited macropores with a pore size of 77.66 nm. Preliminary sorption experiments were carried out and the βCD-BIMOTs-TDI polymer showed enhanced sorption capacity and high removal towards phenols. Based on preliminary sorption experiment, 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and 2,4-dinitrophenol (2,4-DNP) were selected for batch adsorption study. The removal was found to be pH dependent, and therefore, pH 6 was selected for the adsorption process of 2,4-DCP and 2,4,6-TCP since optimum removal was observed at this range. In comparison, pH 4 was selected for the adsorption of 2,4-DNP. A kinetic analysis showed that the pseudo-second-order equation provided better fit for the adsorption of the studied phenols (correlation coefficient (R2) values ranged from 0.9996-1) with 120 min as the equilibrium time. The adsorption process on βCDBIMOTs- TDI was found to be in the order of 2,4-DNP > 2,4,6-TCP > 2,4-DCP. Meanwhile, external and intraparticle diffusion simultaneously occurred during the iv adsorption process of 2,4-DCP, 2,4,6-TCP, and 2,4-DNP onto βCD-BIMOTs-TDI, but it was not a rate determining step. As for the study of isotherm, Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich’s models were studied, and Freundlich’s isotherm was found to fit well for the adsorption of 2,4-DCP, and 2,4,6-TCP with R2>0.97 for all studied temperatures. On the other hand, Langmuir’s model was found to fit well with the adsorption of 2,4-DNP on βCD-BIMOTs-TDI. Besides, the thermodynamics results showed that the adsorption process of 2,4-DCP was exothermic since a negative value of ΔH° (-18.10) was obtained, while the positive values of ΔH° (40.27, and 2.38) indicated that the adsorption process of 2,4,6-TCP, and 2,4-DNP had been endothermic. In addition, adsorption mechanism was studied and was proposed by considering inclusion complex and π-π interaction between modified β-CD functionalized IL (βCDBIMOTs) with one selected phenol compound (2,4-DCP). Apart from that, a new method was developed by applying βCD-BIMOTs-TDI as an adsorbent material for solid phase extraction (SPE) of phenols in water samples by using Gas Chromatography–Flame Ionization Detector (GC-FID). Six different types of phenols; 2-chlorophenol (2-CP), 2-nitrophenol (2-NP), 2,4-dichlorophenol (2,4-DCP), 4- chlorophenol (4-CP), 4-chloro-3-methylphenol (4-CMP), and 2,4,6-Trichlorophenol (2,4,6-TCP) as model analytes, were extracted on a βCD-BIMOTs-TDI SPE cartridge. The optimum experimental condition was 15 mL of sample volume (sample at pH 6), and 2 mL of methanol containing 1% acetic acid as an eluent solvent. The developed method (βCD-BIMOTs-TDI-SPE) was then compared with other adsorbents and the obtained results showed that the βCD-BIMOTs-TDI exhibited higher extraction recovery due to the unique structure and properties. High sensitivity (detection limits 0.23-0.35 μg/L) and good recoveries (87%-116%) were achieved with satisfactory relative standard deviation (RSDs) (0.1-1.7%). Finally, under optimized condition, v βCD-BIMOTs-TDI was applied as an SPE sorbent for determination of phenols in river and tap waters, prior to GC-FID separation

Advanced Materials as Adsorbents in Microextractions for the Determination of Contaminants: A Mini Review

The widespread presence of contaminants in water demands reliable and practical analytical methods to monitor them. However, before their determination, a sample pretreatment step is necessary. This has conventionally been performed using liquid-liquid extraction (LLE) or solid-phase extraction (SPE). Advances in material sciences have since been capitalized on, with new adsorbents used in conjunction with new sample pretreatment techniques based on microextractions. In this mini-review, we showcase some of our previously reported work that demonstrates how advanced materials such as graphene, molecularly imprinted polymers (MIPs), and polymeric cyclodextrins can be used as adsorbents for the determination of contaminants such as bisphenol A, steroids, sulfonamide antibiotics, and antimicrobial agents. These adsorbents formed an important component in the micro-solid phase extraction that was used for the pretreatment of the sample. A brief introduction to the adsorbents studied and evolution of extractions is provided. The distinctive features of the analytical methods used in the real sample analysis of the stated contaminants are highlighted. © 2019 Faculty of Engineering, Universitas Indonesia

Simple and sensitive electrokinetic supercharging in capillary electrophoresis for online preconcentration and separation of secbumeton in water samples

This study describes an electrokinetic supercharging for online preconcentration capillary electrophoresis (CE) technique of secbumeton in water samples. Important CE separation and preconcentration conditions, such as concentration and pH of the background electrolyte, applied voltage and ultraviolet wavelength, type and injection time of the terminating electrolyte, and injection time of the leading electrolyte and sample were investigated and optimized. The optimum conditions involved hydrodynamic injection of leading electrolyte (100 mM sodium chloride, 30 s, 50 mbar), electrokinetic injection of the sample as high as 250 s (at +7 kV voltage), and hydrodynamic injection of terminating electrol7te (100 mM Tris buffer, 40 s, 50 mbar). This strategy enhanced secbumeton detection sensitivity up to 3847-fold and 226-fold when compared with hydrodynamic and electrokinetic injection, respectively, providing a limit of detection as low as 0.03 μg L-1with good repeatability (relative standard deviation < 4%, n = 5). Wide linear range (0.1-500 μg L-1) with good linearity (R2= 0.9997) was obtained. The limit of detection was adequate for the analysis of secbumeton in water samples with concentrations lower than its maximum residual limit (0.1 μg L-1). The developed method was applied to environmental water samples, and recoveries were between 85.7 and 105.6%

Polyaniline-dicationic ionic liquid coated with magnetic nanoparticles composite for magnetic solid phase extraction of polycyclic aromatic hydrocarbons in environmental samples

In this present study, magnetic nanoparticles (MNPs) nanocomposites modified with polyaniline (PANI) coated newly synthesised dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesised as new generation material for magnetic solid phase extraction (MSPE). MNP-PANI-DICAT was characterised by FT-IR NMR, CHN, BET, SEM, TEM, and VSM techniques and the results were compared with MNP-PANI and native MNP. This new material was applied as a magnetic adsorbent for the pre-concentration and separation of polycyclic aromatic hydrocarbons (PAHs) due to the π–π interaction between polyaniline shell and dicationic ionic liquid (DICAT) with PAHs compounds. Under the optimal conditions, the proposed method was evaluated and applied for the analysis of PAHs in environmental samples using gas chromatography-mass spectrometry (GC-MS). The validation method showed good linearity (0.005–500 µg L−1) with the coefficient of determination (R2) > 0.999. The limits of detection (LOD) and quantification (LOQ) of the developed method (MNP-PANI-DICAT-MSPE) were in the range of 0.0008–0.2086 µg L−1 and 0.0024–0.6320 µg L−1, respectively. The enrichment factor (EF) of PAHs on MNP-PANI-DICAT-MSPE were in the range of 7.546–29.632. The extraction recoveries of natural water, sludge, and soil samples were ranged from 80.2% to 111.9% with relative standard deviation (RSD) less than 5.6%. The newly synthesised MNP-PANI-DICAT possess good sensitivity, reusability, and fast extraction of PAHs under the MSPE procedure in various environmental samples

Cytotoxicity of Plant-Mediated Synthesis of Metallic Nanoparticles: A Systematic Review

In the field of medicine, nanomaterials, especially those derived using the green method, offer promise as anti-cancer agents and drug carriers. However, the biosafety of metallic nanoparticles used as anti-cancer agents remains a concern. The goal of this systematic review was to compare the cytotoxicity of different plant-mediated syntheses of metallic nanoparticles based on their potency, therapeutic index, and cancer cell type susceptibility in the hopes of identifying the most promising anti-cancer agents. A literature search of electronic databases including Science Direct, PubMed, Springer Link, Google Scholar, and ResearchGate, was conducted to obtain research articles. Keywords such as biosynthesis, plant synthesis, plant-mediated, metallic nanoparticle, cytotoxicity, and anticancer were used in the literature search. All types of research materials that met the inclusion criteria were included in the study regardless of whether the results were positive, negative, or null. The therapeutic index was used as a safety measure for the studied compound of interest. Data from 76 selected articles were extracted and synthesised. Seventy-two studies reported that the cytotoxicity of plant-mediated synthesis of metallic nanoparticles was time and/or dose-dependent. Biosynthesised silver nanoparticles demonstrated higher cytotoxicity potency compared to gold nanoparticles synthesised by the same plants (Plumbago zeylanica, Commelina nudiflora, and Cassia auriculata) irrespective of the cancer cell type tested. This review also identified a correlation between the nanoparticle size and morphology with the potency of cytotoxicity. Cytotoxicity was found to be inversely proportional to nanoparticle size. The plant-mediated syntheses of metallic nanoparticles were predominantly spherical or quasi-spherical, with the median lethal dose of 1&ndash;20 &micro;g/mL. Nanoparticles with other shapes (triangular, hexagonal, and rods) were less potent. Metallic nanoparticles synthesised by Abutilon inducum, Butea monosperma, Gossypium hirsutum, Indoneesiella echioides, and Melia azedarach were acceptably safe as anti-cancer agents, as they had a therapeutic index of &gt;2.0 when tested on both cancer cells and normal human cells. Most plant-mediated syntheses of metallic nanoparticles were found to be cytotoxic, although some were non-cytotoxic. The results from this study suggest a focus on a selected list of potential anti-cancer agents for further investigations of their pharmacodynamic/toxicodynamic and pharmacokinetic/toxicokinetic actions with the goal of reducing the Global Burden of Diseases and the second leading cause of mortality

Removal of phthalates in aqueos samples using non-ionic silicone surfactant mediated cloud point extraction via spectrophotometry [Penyingkiran ftalat dalam sampel akues menggunakan teknik pengekstrakan titik awan surfaktan silikon tidak berionik dengan spektrofotometri]

Removal of phthalates in environmental compartments become crucial in recent years due to the growing global concern about the health effects of phthalates. In this study, a greener method based on cloud point extraction procedure was developed for the removal of selected phthalates in environmental samples using non-ionic silicone surfactant (DC193C). The parameters affecting the extraction efficiency, such as the surfactant concentration, salt types, salt concentration, temperature and incubation time were evaluated and optimized. Good linearity with correlation coefficients (R2) in the range of 0.9963 – 0.9988 for all calibration curves was obtained. The proposed method was applied in removing the diethhylhexyl phthalate and dibutyl phthalate in river water samples under optimized conditions with satisfactory recoveries in the range of 82 – 98%. © 2019, Malaysian Society of Analytical Sciences. All rights reserved