Noorfatimah Yahaya

Micellar electrokinetic chromatography method for the simultaneous determination of furanic compounds in honey and vegetable oils

A simple micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of 2-furfural (2-F), 3-furfural (3-F), 5-methylfurfural (5-MF), 5-hydroxymethylfurfural (5-HMF), 2-furoic acid (2-FA) and 3-furoic acid (3-FA) in honey and vegetable oils is described. Parameters affecting the separation such as pH, buffer and surfactant concentrations, applied voltage, capillary temperature, injection time and capillary length were studied and optimized. The separation was carried out in normal polarity mode at 20 °C, 22 kV and using hydrodynamic injection (17 s). The separation was achieved in a bare fused-silica capillary (46 cm × 50 μm i.d.) with a background electrolyte of 75 mM phosphoric acid (pH 7.3), containing 200 mM of sodium dodecyl sulphate (SDS). The detection wavelengths were at 200 nm (2-FA and 3-FA) and 280 nm (2-F, 3-F, 5-MF, 5-HMF). The furfurals were well separated in less than 20 min. The method was validated in terms of linearity, limit of detection and quantitation, precision and recoveries. Calibration curves of the six furfurals were well correlated (r(2)>0.991) within the range 1-25 μg mL(-1). Relative standard deviations of intra- and inter-day migration times and corrected peak areas ≤9.96% were achieved. The limit of detection (signal:noise, 3) was 0.33-0.70 μg mL(-1) whereas the limit of quantitation (signal:noise, 10) was 1.00-2.12 μg mL(-1). The method was applied to the determination of furanic compounds in honeys and vegetable oils (palm, walnut, grape seed and rapeseed). The effects of thermal treatment and gamma irradiation on the formation of the furanic compounds in honey were also investigated.

Rapid ultrasound assisted emulsification micro-solid phase extraction based on molecularly imprinted polymer for HPLC-DAD determination of bisphenol A in aqueous matrices

Molecularly imprinted polymer (MIP) was employed as sorbent in ultrasound assisted emulsification molecularly imprinted polymer micro-solid phase extraction (USAE-MIP-µ-SPE) of bisphenol A (BPA) in water, beverages and the aqueous liquid in canned foods prior to high performance liquid chromatography-diode array detector (HPLC-DAD) analysis. Several effective variables, such as types of emulsification solvent and its volume, types of desorption solvent and its volume, salting out effect, pH of sample solution, mass of sorbent, extraction and desorption time, and sample volume, were optimized comprehensively. Under the optimized USAE-MIP-µ-SPE and HPLC-DAD conditions, the method demonstrated good linearity over the range of 0.5-700μgL-1 with a coefficient determination of R2=0.9973, low limit of detection (0.07μgL-1), good analyte recoveries (82.2-118.9%) and acceptable RSDs (0.7-14.2%, n=3) with enrichment factor of 49. The method was applied to thirty samples of drinking water, mineral water, river water, lake water, as well as beverages and canned foods, the presence of BPA was identified in four samples. The proposed method showed good selectivity and reusability for extraction of BPA, and hence the USAE-MIP-µ-SPE is rapid, simple, cost effective and environmentally friendly.

An ionic liquid loaded magnetically confined polymeric mesoporous adsorbent for extraction of parabens from environmental and cosmetic samples

An ionic liquid loaded magnetically confined polymeric mesoporous adsorbent based magnetic solid phase extraction (MSPE) procedure has been developed for the extraction and pre-concentration of parabens, namely methyl paraben (MP), ethyl paraben (EP), propyl paraben (PP) and butyl paraben (BP) from environmental and cosmetic samples. In this study, hydrophilic ionic liquids (ILs), 1-butyl-3-methylimidazolium chloride (BMIM-Cl) was loaded onto the surface of MNP grafted β-cyclodextrin polymer (MNP-βCD-TDI) to form a new ionic liquid based magnetic polymeric adsorbent (IL-MNP-βCD-TDI). This is a new approach for the extraction of parabens followed by high-performance liquid chromatography with diode-array detection (HPLC-DAD). The formation of IL-MNP-βCD-TDI was characterized by FT-IR, CHN, BET, SEM, TEM, VSM and XRD techniques and compared with native MNPs and MNP-βCD-TDI. Several variables were optimized thoroughly including the types of adsorbents used, concentration of ionic liquid loaded, amount of adsorbent, extraction and desorption time, types and volumes of desorption solvent, sample pH, ionic strength, and sample volume. Under-optimized conditions, excellent linearity was achieved in the range of 0.3–500.0 μg L−1 for MP and EP, and 0.1–500.0 μg L−1 for PP and BP, with a correlation coefficient of R2 > 0.999. High sensitivity with limits of detection (LODs: 0.02 to 0.09 μg L−1) and quantification (LOQs: 0.05 to 0.28 μg L−1), and good recoveries (80.3–117.3%) were obtained with satisfactory relative standard deviations (RSDs: 1.1–14.9%). The developed material (IL-MNP-βCD-TDI) proved to be a simple and effective alternative adsorbent for the extraction of parabens from various types of environmental water samples and cosmetic products.

A study on the removal of propyl, butyl, and benzyl parabens via newly synthesised ionic liquid loaded magnetically confined polymeric mesoporous adsorbent

This study investigated the effectiveness of ionic liquids (ILs) loaded onto the surface of a polymeric adsorbent (βCD-TDI) grafted with modified magnetic nanoparticles (MNPs) via an analysis of water treatment, which resulted in high removal of selected endocrine-disrupting chemicals (parabens). The syntheses of MNPs, MNP-βCD-TDI, and IL-MNP-βCD-TDI were characterised and compared using Fourier transform infrared (FT-IR) spectroscopy, carbon–hydrogen–nitrogen (CHN) analysis, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer–Emmett–Teller (BET) method, thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The results of SEM and TEM indicated that the pore size distribution exhibited mesoporous characteristics with a small surface area (BET analysis: 42.95 m2 g−1). Furthermore, a preliminary sorption experiment demonstrated the ability of IL-MNP-βCD-TDI to enhance not only the sorption capacity, but also the removal of propyl paraben (PP), butyl paraben (BP), and benzyl paraben (ArP). The adsorption process appeared to be pH-dependent, and hence the optimum pH of 6 was selected for a subsequent batch adsorption study of all the studied parabens with an equilibrium time of 80 min. Next, in an attempt to investigate the interactions that occur between the adsorbent and the adsorbates, adsorption kinetics and isotherm studies were performed. All the studied parabens were found to best fit pseudo-second-order kinetics and the Freundlich isotherm with R2 > 0.98 at room temperature (298 K). The interaction of the host–guest inclusion complex and the π–π interaction between βCD and a selected paraben compound (ArP) were identified by performing 1H nuclear magnetic resonance (NMR), together with ultraviolet-visible (UV-vis) spectroscopic analysis. Finally, the adsorption efficiency of the developed material was practically tested on tap water, drain water, and industrial wastewater, which revealed a significant removal of parabens of up to 60–90% in comparison with a prior analysis.

Thiol-functionalized magnetic carbon nanotubes for magnetic micro-solid phase extraction of sulfonamide antibiotics from milks and commercial chicken meat products

Thiol-functionalized magnetic carbon nanotubes (TMCNTs) were employed as the sorbent in the magnetic micro-solid phase extraction (M-µ-SPE) of sulfonamide antibiotics (SAs) in water, milks and chicken meat products prior to high performance liquid chromatography-diode array detector (HPLC-DAD) analysis. The synthesized sorbent was characterized by several spectroscopic techniques. Optimum conditions were: 20 mg of TMCNTs at pH 4, 2 min extraction time, 10% addition of salt and 30 mL of sample volume. Under the optimized TMCNTs-M-µ-SPE and HPLC-DAD conditions, the method showed good linearity in the range of 0.1-500 µg L-1 (r2 ≥ 0.9950), low limits of detection (0.02-1.5 µg L-1), good analytes recovery (80.7-116.2%) and acceptable RSDs (0.3-7.7%, n = 15). The method was applied to tap water (1), milks (15) and commercial chicken meat products (35), SAs were detected in five chicken meat samples (3.0-25.7 µg L-1). The method is critically compared to those reported in the literature.

Smart combination of β-cyclodextrin polymer-conjugated magnetic nanosorbent for potential adsorption of deoxyribonucleic acid

ABSTRACT We reported the synthesis and characterization of Fe3O4 magnetic nanoparticles modified β-cyclodextrin polymer (MNP@βCD-TDI) for the adsorption of deoxyribonucleic acid (DNA). The synthesized MNP@βCD-TDI was characterized by Fourier Transform Infra-Red spectroscopy and Vibrating Sample Magnetometer. Experiments were performed in a batch mode and parameters that affected the DNA adsorption were investigated. An evaluation of the adsorption behavior revealed that Freundlich model and pseudo-second-order fit the equilibrium data. The adsorption efficiency of DNA was found to be at after being recycled three times. This study could be used as a general platform for future work on DNA adsorption and enrichment.

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 1–20 µg/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 >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.

Kaedah pengekstrakan mikro ultrabunyi dengan bantuan surfaktan meningkatkan pengemulsian bergabung dengan kromatografi gas-spektrometri jisim bagi penentuan polisiklik aromatik hidrokarbon terpilih di dalam sampel akueus

A simple and rapid microextraction method termed as ultrasound-assisted surfactant enhanced emulsification microextraction (UASEME) was developed for the determination of fluoranthene (FLU) and phenanthrene (PHE) in aqueous samples followed by gas chromatography-mass spectrometry (GC-MS). Six important parameters, that affect the extraction efficiency of polycyclic aromatic hydrocarbons (PAHs) were evaluated and the results were as follows; extraction solvent (toluene), volume of extraction solvent (30 μL), surfactant (Tween 20), volume of surfactant (15 μL), extraction time (2 minutes) and with no salt addition. Under the optimum conditions, the method showed good linearity over the concentration range from 1 – 1000 μg L- 1 with correlation coefficients (R² ≥ 0.9932), acceptable limits of detection (0.3 μg L- 1) and limits of quantification (1.0 μg L- 1) for both analytes. Good relative recovery values, in the range of 91.75 – 104.1%, were obtained for tap water samples. The relative standard deviations (RSDs) were 1.62 – 10.32% (n = 3). The proposed method was applied for the determination of FLU and PHE in tap water and sugarcane juices.

Removal of Cu (II) and Cd (II) Ions from Environmental Water Samples by Using Cellulose Acetate Membrane

Cellulose Acetate Membrane (CAM) which has been prepared by using a casting technique was utilized as an adsorbent for heavy metal ions adsorption. The CAM was characterized by Field Emission Scanning Electron Microscopy (FESEM), BET surface area (BET) and Fourier Transform Infrared Analysis (FTIR). The adsorption of Cu (II) and Cd (II) ions on CAM were investigated. The influences of several variables such as pH, adsorbance dosage, initial metal concentration, kinetic parameter, desorption and reusability on the adsorption capacity of the CAM was investigated in a batch adsorption mode. The adsorption capacity increased with the increasing of initial concentration of Cu (II) and Cd (II) solutions and followed the Freundlich model and pseudo second order kinetic mechanism. Desorption of metal ions was accomplished with 1 M Sulphuric acid and Hydrochloric acid solution for Cu (II) and Cd (II) ions. The adsorption capacity did not change significantly in reusability study when three adsorption experimental cycles were conducted. In conclusion, CAM is possible to be used as an alternative adsorbent for the removal of heavy metal ions from environmental water samples.