Displaying publications 1 - 20 of 22 in total

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  1. Raoov M, Mohamad S, Abas MR
    J Hazard Mater, 2013 Dec 15;263 Pt 2:501-16.
    PMID: 24231314 DOI: 10.1016/j.jhazmat.2013.10.003
    Cyclodextrin-ionic liquid polymer (βCD-BIMOTs-TDI) was firstly synthesized using functionalized β-Cyclodextrin (CD) with 1-benzylimidazole (BIM) to form monofunctionalized CD (βCD-BIMOTs) and was further polymerized using toluene diisocyanate (TDI) linker to form insoluble βCD-BIMOTs-TDI. SEM characterization result shows that βCD-BIMOTs-TDI exhibits macropore size while the BET result shows low surface area (1.254 m(2)g(-1)). The unique properties of the ILs allow us to produce materials with different morphologies. The adsorption isotherm and kinetics of 2,4-dichlorophenol (2,4-DCP) onto βCD-BIMOTs-TDI is studied. Freundlich isotherm and pseudo-second order kinetics are found to be the best to represent the data for 2,4-DCP adsorption on the βCD-BIMOTs-TDI. The presence of macropores decreases the mass transfer resistance and increases the adsorption process by reducing the diffusion distance. The change in entropy (ΔS°) and heat of adsorption (ΔH°) for 2,4-DCP on βCD-BIMOTs-TDI were estimated as -55.99 J/Kmol and -18.10 J/mol, respectively. The negative value of Gibbs free energy (ΔG°) indicates that the adsorption process is thermodynamically feasible, spontaneous and chemically controlled. Finally, the interactions between the cavity of βCD-BIMOTs and 2,4-DCP are investigated and the results shows that the inclusion of the complex formation and π-π interaction are the main processes involved in the adsorption process.
  2. Raoov M, Mohamad S, Abas MR
    Int J Mol Sci, 2014;15(1):100-19.
    PMID: 24366065 DOI: 10.3390/ijms15010100
    β-Cyclodextrin-ionic liquid polymer (CD-ILP) was first synthesized by functionalized β-cyclodextrin (CD) with 1-benzylimidazole (BIM) to form monofunctionalized CD (βCD-BIMOTs) and was further polymerized using a toluene diisocyanate (TDI) linker to form insoluble CD-ILP (βCD-BIMOTs-TDI). The βCD-BIMOTs-TDI polymer was characterized using various tools and the results obtained were compared with those derived from the native β-cyclodextrin polymer (βCD-TDI). The SEM result shows that the presence of ionic liquid (IL) increases the pore size, while the thermo gravimetric analysis (TGA) result shows that the presence of IL increases the stability of the polymer. Meanwhile, Brunauer-Emmett-Teller (BET) results show that βCD-BIMOTs-TDI polymer has 1.254 m(2)/g surface areas and the Barret-Joyner-Halenda (BJH) pore size distribution result reveals that the polymer exhibits macropores with a pore size of 77.66 nm. Preliminary sorption experiments were carried out and the βCD-BIMOTs-TDI polymer shows enhanced sorption capacity and high removal towards phenols and As(V).
  3. Mohd NI, Zain NNM, Raoov M, Mohamad S
    R Soc Open Sci, 2018 Apr;5(4):171500.
    PMID: 29765632 DOI: 10.1098/rsos.171500
    A new cloud point methodology was successfully used for the extraction of carcinogenic pesticides in milk samples as a prior step to their determination by spectrophotometry. In this work, non-ionic silicone surfactant, also known as 3-(3-hydroxypropyl-heptatrimethylxyloxane), was chosen as a green extraction solvent because of its structure and properties. The effect of different parameters, such as the type of surfactant, concentration and volume of surfactant, pH, salt, temperature, incubation time and water content on the cloud point extraction of carcinogenic pesticides such as atrazine and propazine, was studied in detail and a set of optimum conditions was established. A good correlation coefficient (R2 ) in the range of 0.991-0.997 for all calibration curves was obtained. The limit of detection was 1.06 µg l-1 (atrazine) and 1.22 µg l-1 (propazine), and the limit of quantitation was 3.54 µg l-1 (atrazine) and 4.07 µg l-1 (propazine). Satisfactory recoveries in the range of 81-108% were determined in milk samples at 5 and 1000 µg l-1, respectively, with low relative standard deviation, n = 3 of 0.301-7.45% in milk matrices. The proposed method is very convenient, rapid, cost-effective and environmentally friendly for food analysis.
  4. Muniandy Y, Mohamad S, Raoov M
    RSC Adv, 2024 Apr 10;14(17):11977-11985.
    PMID: 38623288 DOI: 10.1039/d4ra00940a
    A green method based on magnetic micro-solid phase extraction (MNP-TW-μ-SPE) of tea waste impregnated with magnetic nanoparticles (MNP-TW) was developed for the extraction of ibuprofen (IBP) in water samples prior to UV-Vis spectrophotometric analysis. Experimenting parameters that affect the extraction efficiency of IBP, such as pH of the sample solution, sorbent dosage, extraction time, ionic strength, volume of the sample, type of desorption solvent, desorption time, and desorption volume, were studied and optimized in detail. The characterization studies for the MNP-TW were carried out by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectrometry (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, a vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). Under the optimum conditions, the linearity ranges from 30 to 700 μg L-1 for IBP, with determination coefficients (R2) of 0.9983. The limit of detection (LOD) and limit of quantification (LOQ) were 9.40 μg L-1 and 28.50 μg L-1, respectively. The method also demonstrated good precision in reproducibility (RSD ≤ 1.53%), repeatability (RSD ≤ 1.48%), and recovery (86-115%). This method represents the advantages of low solvent consumption, flexibility, and better sensitivity compared to other studies employing spectrophotometric analysis. The usage of tea waste in the extraction process presents many advantages, as it is biodegradable, versatile, and contributes to an intelligent and sustainable economic strategy projected toward a circular economy approach.
  5. Raoov M, Mohamad S, bin Abas MR, Surikumaran H
    Talanta, 2014 Dec;130:155-63.
    PMID: 25159393 DOI: 10.1016/j.talanta.2014.06.067
    Cyclodextrin-ionic liquid polymer (βCD-BIMOTs-TDI) is a new class of macroporous material and has great potential to be used as an SPE adsorbent material for extraction of phenols in river water samples. Six phenols, as model analytes, were extracted on a βCD-BIMOTs-TDI SPE cartridge, and then, eluted with 2 mL of methanol containing 1% acetic acid. 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 eluent concentration was determined by using Gas Chromatography-Flame Ionization Detector (GC-FID). Under optimized condition, high sensitivity (detection limits 0.23-0.35 µg/L) and good recoveries (87-116%) were achieved with satisfactory relative standard deviation (RSD) (0.1-1.7%). The developed 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. Finally, the βCD-BIMOTs-TDI was applied as a solid phase extraction sorbent for phenols determination under optimized condition, in river and tap waters, prior to the GC-FID separation.
  6. Noorashikin MS, Raoov M, Mohamad S, Abas MR
    Int J Mol Sci, 2013;14(12):24531-48.
    PMID: 24351832 DOI: 10.3390/ijms141224531
    A cloud point extraction (CPE) process using non-ionic surfactant (DC193C) to extract selected paraben compounds from water samples was investigated using reversed phase high performance liquid chromatography (RP-HPLC). The CPE process with the presence of β-cyclodextrin (βCD) functionalized ionic liquid as a modifier (CPE-DC193C-βCD-IL) is a new extraction technique that has been applied on the optimization of parameters, i.e., pH, βCD-IL concentration and phase volume ratio. This CPE-DC193C-βCD-IL method is facilitated at 30 °C, showing great losses of water content in the surfactant-rich phase, resulting in a high pre-concentration factor and high distribution coefficient. The developed method CPE-DC193C-βCD-IL did show enhanced properties compared to the CPE method without the modifier (CPE-DC193C). The developed method of CPE-DC193C-βCD-IL gives an excellent performance on the detection of parabens from water samples with the limit of detection falling in the range of 0.013-0.038 µg mL-1. Finally, the inclusion complex formation, hydrogen bonding, and π-π interaction between the βCD-IL, benzyl paraben (ArP), and DC 193C were proven using 1H NMR and 2D NOESY spectroscopy.
  7. Mohd NI, Gopal K, Raoov M, Mohamad S, Yahaya N, Lim V, et al.
    Talanta, 2019 May 01;196:217-225.
    PMID: 30683354 DOI: 10.1016/j.talanta.2018.12.043
    The non-ionic silicone surfactant (OFX 0309) has been applied in cloud point extraction for the extraction of triazine herbicides in food samples. Evidence has shown that the non-ionic silicone surfactant demonstrated a good performance as an extractor toward triazine herbicides. In this present study, OFX 0309 surfactant was combined with activated charcoal (AC) due to their valuable properties. Activated charcoal modified with non-ionic silicone surfactant coated with magnetic nanoparticles (AC-OFX MNPs) was synthesized and characterized by FT-IR, VSM, SEM, TEM and BET. This novel material was applied as a magnetic adsorbent for the pre-concentration and separation of triazine herbicides due to hydrophobic interaction between polysiloxane polyether of OFX 0309 surfactant and triazine herbicides. Under optimal conditions, the proposed magnetic solid phase extraction method using AC-OFX MNPs adsorbent was applied to extract triazine herbicides from selected milk and rice samples using high performance liquid chromatography coupled with diode array detector. The validation method revealed a good linearity (1 - 500 μg L-1) with the coefficient of determination (R2) in the range of 0.992-0.998 for the samples. The limits of detection (LOD) of the developed method were 0.04 - 0.05 µg L-1 (milk sample) and 0.02 - 0.05 µg L-1 (rice sample). The limits of quantification (LOQ) were 0.134 - 0.176 µg L-1 (milk sample) and 0.075 - 0.159 µg L-1 (rice sample). The recoveries of the triazine compounds ranged from 81% to 109% in spiked milk samples and from 81% to 111% in spiked rice samples, with relative standard deviations (RSD) values lower than 13.5% and 12.1% for milk and rice samples, respectively. To the best of our knowledge, this is the first study that have investigated the use of magnetic nanoparticles coated activated charcoal modified with OFX 0309 surfactant for pretreatment of triazine herbicides in food samples analysis for simultaneous separation of organic pollutants.
  8. Usman UA, Yusoff I, Raoov M, Hodgkinson J
    Environ Geochem Health, 2020 Oct;42(10):3079-3099.
    PMID: 32180058 DOI: 10.1007/s10653-020-00543-0
    The research study was carried out to evaluate trace metals (Pb, Cd, Se, Al, Mn, Cu, Zn, Fe, As, Ni, Cr, and Ag) concentrations in groundwater of Lorong Serai 4, Hulu Langat, Selangor, Malaysia. Additionally, the research study focused on determining non-carcinogenic and carcinogenic health risks, sources of the contaminants, and effective remediation methods. The results show that the concentration levels of Pb, Cd, Se, Al, Cu, Zn, Ni, Cr, and Ag are lower than their corresponding permissible limits, while Fe, Mn, and As concentrations exceed their acceptable limit. The hazard index of the groundwater in the area exceeded the acceptable limit, showing the rate of carcinogenic and non-carcinogenic health effects associated with the water. The findings also indicate that the lifetime cancer risk is high compared to the maximum limits of lifetime cancer risk from the drinking water (10-6 to 10-4). The groundwater geochemical data of the area are used in establishing the source of Fe, Mn, and As metal ions. Evaluation of Fe2+/Fe3+ and S2-/SO42- redox couples and thermodynamic modelling indicates that the groundwater of the area is in redox disequilibrium. The groundwater samples contain aqueous iron sulphate, which is supersaturated, ferrous carbonate and aluminium sulphate that are saturated. The main state of redox disequilibrium is governed by mineral precipitation and dissolution. Aqueous arsenic and manganese are possibly derived from the dissolution of pyrite (arsenopyrite) and amorphous oxide-hydroxides, respectively. The high concentration of iron in the shallow groundwater in the area is primarily the result of silicate rock weathering of ferroan igneous and metamorphic minerals with a minor contribution from the oxidation of iron sulphides. Magnetite coated with graphene oxide (Fe3O4-GO) nanoparticles (NPs) was synthesized and characterized, and the adsorption preliminary experiments were carried out; and the Fe3O4-GO NPs show enhanced removal (Fe > As > Mn) capacity over graphene oxide (GO).
  9. Shahriman MS, Mohamad S, Mohamad Zain NN, Raoov M
    Talanta, 2023 Mar 01;254:124188.
    PMID: 36521327 DOI: 10.1016/j.talanta.2022.124188
    A paper-based polymeric ionic liquid (p-Poly-(MMA-IL)) was successfully developed by grafting the polymeric ionic liquid on the surface of commercial filter paper (FP) by using the dipping method, presenting a new cost-effective film. The newly developed p-Poly-(MMA-IL) FP was then applied as a paper-based thin-film microextraction (p-TFME) analytical device to extract 14 compounds as representative of five groups of antibiotic drugs, which were sulfonamides, tetracyclines, fluoroquinolones, penicillin and macrolides in environmental water samples. Besides, p-Poly-(MMA-IL) FP, p-Poly-(MMA) FP, and unmodified filter paper were successfully characterised by FTIR, NMR, FESEM, TGA, and XRD techniques. They underwent significant parameters optimisation, which affected the extraction efficiency. Under optimal conditions, the proposed (p-Poly-(MMA-IL) FP-TFME) device method was evaluated and applied to analyse multi-class antibiotic drugs in environmental water samples by using a liquid chromatography-mass spectrometry (LC-MS). The validation method showed that a good linearity (0.1 μg L-1 - 500 μg L-1) was noted (R2 > 0.993, n = 3). Detection and quantification limits were within 0.05 μg L-1 - 4.52 μg L-1 and 0.15 μg L-1 - 13.6 μg L-1, respectively. The relative standard deviation (RSD) values ranged at 1.4%-12.2% (intra-day, n = 15) and 4.4%-11.0% (inter-day, n = 10). The extraction recoveries of environmental water samples ranged from 79.1% to 126.8%, with an RSD of less than 15.4% (n = 3). The newly developed paper-based polymeric ionic liquid (p-Poly-(MMA-IL) FP) for analysis of multi-class antibiotic drugs under the p-TFME analytical device procedure was successfully achieved with limited sample volume and organic solvent, fast extraction, and feasible in daily analysis. The detection concentration and relative RSD of multi-class antibiotics determined in various environmental water samples by the proposed method (n = 5) were within 0.44 μg L-1 - 54.41 μg L-1 and 0.69%-15.56%, respectively. These results signified the potential of the p-Poly-(MMA-IL) FP-TFME device as an efficient, sensitive and environmentally friendly approach for analysing antibiotics.
  10. Md Yusoff M, Yahaya N, Md Saleh N, Raoov M
    RSC Adv, 2018 Jul 16;8(45):25617-25635.
    PMID: 35539765 DOI: 10.1039/c8ra03408g
    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 R 2 > 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.
  11. Mohamad S, Surikumaran H, Raoov M, Marimuthu T, Chandrasekaram K, Subramaniam P
    Int J Mol Sci, 2011;12(9):6329-45.
    PMID: 22016662 DOI: 10.3390/ijms12096329
    This study focuses on the synthesis and characterization of the inclusion complex of β-Cyclodextrin (β-CD) with dicationic ionic liquid, 3,3'-(1,4-Phenylenebis [methylene]) bis(1-methyl-1H-imidazol-3-ium) di(bromide) (PhenmimBr). The inclusion complex was prepared at room temperature utilizing conventional kneading technique. Proton ((1)H) NMR and 2D ((1)H-(1)H) COSY NMR were the primary characterization tools employed to verify the formation of the inclusion complex. COSY spectra showed strong correlations between protons of imidazolium and protons of β-CD which indicates that the imidazolium ring of PhenmimBr has entered the cavity of β-CD. UV absorption indicated that β-CD reacts with PhenmimBr to form a 2:1 β-CD-PhenmimBr complex with an apparent formation constant of 2.61 × 10(5) mol&(-2) L(2). Other characterization studies such as UV, FT-IR, XRD, TGA, DSC and SEM studies were also used to further support the formation of the β-CD-PhenmimBr inclusion complex.
  12. Boon YH, Mohamad Zain NN, Mohamad S, Osman H, Raoov M
    Food Chem, 2019 Apr 25;278:322-332.
    PMID: 30583379 DOI: 10.1016/j.foodchem.2018.10.145
    Poly(β-cyclodextrin functionalized ionic liquid) immobilized magnetic nanoparticles (Fe3O4@βCD-Vinyl-TDI) as sorbent in magnetic µ-SPE was developed for the determination of selected polycyclic aromatic hydrocarbons (PAHs) in rice samples coupled with gas chromatographic-flame ionization detector (GC-FID). The nanocomposite was characterized by various tools and significant parameters that affected the extraction efficiency of PAHs were investigated. The calibration curves were linear for the concentration ranging between 0.1 and 500 μg kg-1 with correlation determinations (R2) from 0.9970 to 0.9982 for all analytes. Detection limits ranged at 0.01-0.18 μg kg-1 in real matrix. The RSD values ranged at 2.95%-5.34% (intra-day) and 4.37%-7.05% (inter-day) precision for six varied days. The sorbents showed satisfactory reproducibility in 2.9% to 9.9% range and acceptable recovery values at 80.4%-112.4% were obtained for the real sample analysis. The optimized method was successfully applied to access content safety of selected PAHs for 24 kinds of commercial rice available in Malaysia.
  13. Prabu S, Samad NA, Ahmad NA, Jumbri K, Raoov M, Rahim NY, et al.
    Carbohydr Res, 2020 Nov;497:108138.
    PMID: 32911205 DOI: 10.1016/j.carres.2020.108138
    The behavior of the inclusion behavior of guanosine (GU) with beta-cyclodextrin (β-CD) in the liquid, solid and virtual state were investigated. The absorption and fluorescence spectral were used to determine the inclusion behavior in liquid state. FT-IR, NMR, TGA, DSC, PXRD and FESEM techniques were used to investigate the inclusion behavior in solid-state, meanwhile the virtual state studies are done by molecular docking. The solid inclusion complex (GU: β-CD) was prepared by using the co-precipitation method. The binding constant (K) of (GU: β-CD) was calculated by using Benesi-Hildebrand. Besides that, the 1:1 stoichiometric ratio of inclusion complex was confirmed by using the Benesi-Hildebrand plot and Job's plot of continuous variation method. The most preferable model of GU: β-CD that suggested via molecular docking studies was in good agreement with experimental results. The inclusion complex of GU: β-CD exerted its toxicity effects towards HepG2 cell lines based on the reduced number of cell viability and lowest IC50 value compared to the GU and β-CD viability.
  14. Elencovan V, Joseph J, Yahaya N, Abdul Samad N, Raoov M, Lim V, et al.
    Food Chem, 2021 Aug 10;368:130835.
    PMID: 34416487 DOI: 10.1016/j.foodchem.2021.130835
    A novel deep eutectic solvents (DES) was successfully applied as an emulsifier in vortex assisted liquid-liquid microextraction (VALLME) coupled with gas chromatography-mass spectrometry for the determination of organophosphorus pesticides in honey and fruit samples. Based on the result of toxicity study, DES provides new opportunities for the safe delivery and application. The predominant parameters affecting extraction efficiency were thoroughly optimized and studied in detail. Under optimum parameters, the calibration curve was determined in the concentration range of 0.1 to 200 µgL-1 with excellent determination coefficients values of 0.9989 to 0.9999. Limit of detection and limit of quantification were found to be 0.01 - 0.09 µgL-1 and 0.03 - 0.2 µgL-1, respectively. Application of the developed method to honey and fruit samples gave acceptable recovery values 83 - 109% with relative standard deviation below than 9.5%. The suggested approach has also proven to be simple, cost-effective, rapid, and non-toxic in nature.
  15. Hui BY, Raoov M, Zain NNM, Mohamad S, Osman H
    Crit Rev Anal Chem, 2017 Sep 03;47(5):454-467.
    PMID: 28453309 DOI: 10.1080/10408347.2017.1320936
    The growth in driving force and popularity of cyclodextrin (CDs) and ionic liquids (ILs) as promising materials in the field of analytical chemistry has resulted in an exponentially increase of their exploitation and production in analytical chemistry field. CDs belong to the family of cyclic oligosaccharides composing of α-(1,4) linked glucopyranose subunits and possess a cage-like supramolecular structure. This structure enables chemical reactions to proceed between interacting ions, radical or molecules in the absence of covalent bonds. Conversely, ILs are an ionic fluids comprising of only cation and anion often with immeasurable vapor pressure making them as green or designer solvent. The cooperative effect between CD and IL due to their fascinating properties, have nowadays contributed their footprints for a better development in analytical chemistry nowadays. This comprehensive review serves to give an overview on some of the recent studies and provides an analytical trend for the application of CDs with the combination of ILs that possess beneficial and remarkable effects in analytical chemistry including their use in various sample preparation techniques such as solid phase extraction, magnetic solid phase extraction, cloud point extraction, microextraction, and separation techniques which includes gas chromatography, high-performance liquid chromatography, capillary electrophoresis as well as applications of electrochemical sensors as electrode modifiers with references to recent applications. This review will highlight the nature of interactions and synergic effects between CDs, ILs, and analytes. It is hoped that this review will stimulate further research in analytical chemistry.
  16. Anne JM, Boon YH, Saad B, Miskam M, Yusoff MM, Shahriman MS, et al.
    R Soc Open Sci, 2018 Aug;5(8):180942.
    PMID: 30225083 DOI: 10.1098/rsos.180942
    In this work, we reported the synthesis, characterization and adsorption study of two β-cyclodextrin (βCD) cross-linked polymers using aromatic linker 2,4-toluene diisocyanate (2,4-TDI) and aliphatic linker 1,6-hexamethylene diisocyanate (1,6-HDI) to form insoluble βCD-TDI and βCD-HDI. The adsorption of 2,4-dinitrophenol (DNP) on both polymers as an adsorbent was studied in batch adsorption experiments. Both polymers were well characterized using various tools that include Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller analysis and scanning electron microscopy, and the results obtained were compared with the native βCD. The adsorption isotherm of 2,4-DNP onto polymers was studied. It showed that the Freundlich isotherm is a better fit for βCD-TDI, while the Langmuir isotherm is a better fit for βCD-HMDI. The pseudo-second-order kinetic model represented the adsorption process for both of the polymers. The thermodynamic study showed that βCD-TDI polymer was more favourable towards 2,4-DNP when compared with βCD-HDI polymer. Under optimized conditions, both βCD polymers were successfully applied on various environmental water samples for the removal of 2,4-DNP. βCD-TDI polymer showed enhanced sorption capacity and higher removal efficiency (greater than 80%) than βCD-HDI (greater than 70%) towards 2,4-DNP. The mechanism involved was discussed, and the effects of cross-linkers on βCD open up new perspectives for the removal of toxic contaminants from a body of water.
  17. Yih Hui B, Mohamad Zain NN, Mohamad S, Varanusupakul P, Osman H, Raoov M
    Food Chem, 2020 Jun 01;314:126214.
    PMID: 31972404 DOI: 10.1016/j.foodchem.2020.126214
    Poly(β-cyclodextrin-ionic liquid) grafted magnetic nanoparticles combined with 1-octanol as supramolecular solvents (SUPRASs) presenting new ferrofluid was developed and successfully applied in the dispersive liquid-phase microextraction of seven representative polycyclic aromatic hydrocarbons. One variable at-a-time (OVAT) analysis and response surface methodology (RSM) were used for efficient optimization of the main variables. The calibration curves were found to be linear in the range of 0.1-150 ng mL-1 with correlation of determinations (R2) ranging from 0.9944 to 0.9986. Detection limits ranged at 0.02-0.07 ng mL-1 for all studied PAHs. The intra and inter-day precision values (RSD %) were in the range of 1.80%-7.56% and 2.97%-8.23%, respectively. The ferrofluid showed a satisfactory reproducibility between 1.72% and 5.90%, and acceptable recovery values at 84%-110% were obtained for the real samples analysis. The optimized method was successfully applied to access the content safety of the PAHs studied in a variety of commercial food and beverages available in Malaysia.
  18. Azhari NR, Yahaya N, Mohd Suah FBM, Prabu S, Yih Hui B, Shahriman MS, et al.
    Chirality, 2021 01;33(1):37-50.
    PMID: 33197086 DOI: 10.1002/chir.23285
    A chiral separation method coupled with capillary electrophoresis (CE) analysis for ketoconazole and miconazole enantiomers using chiral selectors such as β-cyclodextrin (β-CD) and hydroxypropyl-β-CD (HP-β-CD) was developed in this study, which included the optimisation, validation and application of the method on the antifungal cream samples. The formation of inclusion complex between the hosts (β-CD and HP-β-CD) and guests (ketoconazole and miconazole) were compared and analysed using ultraviolet-visible spectrophotometry, nuclear magnetic resonance (NMR) spectroscopy and molecular docking methods. Results from the study showed that in a concentration that ranged between 0.25 and 50 mg L-1 , the linear calibration curves of each enantiomer had a high coefficient of regression (R2 > 0.999), low limit of detection (0.075 mg L-1 ) and low limit of quantification (0.25 mg L-1 ). The relative standard deviation (RSD) of the intraday and interday analyses ranged from 0.79% to 8.01% and 3.30% to 11.43%, respectively, while the recoveries ranged from 82.0% to 105.7% (RSD < 7%, n = 3). The most probable structure of the inclusion complexes was proposed based on the findings from the molecular docking studies conducted using the PatchDock server.
  19. Subuhi NEAM, Saad SM, Zain NNM, Lim V, Miskam M, Kamaruzaman S, et al.
    J Sep Sci, 2020 Aug;43(16):3294-3303.
    PMID: 32519432 DOI: 10.1002/jssc.201901194
    In this work, a simple, fast, sensitive, and environmentally friendly method was developed for preconcentration and quantitative measurement of bisphenol A in water samples using gas chromatography with mass spectrometry. The preconcentration approach, namely biosorption-based dispersive liquid-liquid microextraction with extractant removal by magnetic nanoparticles was performed based on the formation of microdroplet of rhamnolipid biosurfactant throughout the aqueous samples, which accelerates the mass transfer process between the extraction solvent and sample solution. The process is then followed by the application of magnetic nanoparticles for easy retrieval of the analyte-containing extraction solvent. Several important variables were optimized comprehensively including type of disperser solvent and desorption solvent, rhamnolipid concentration, volume of disperser solvent, amount of magnetic nanoparticles, extraction time, desorption time, ionic strength, and sample pH. Under the optimized microextraction and gas chromatography with mass spectrometry conditions, the method demonstrated good linearity over the range of 0.5-500 µg/L with a coefficient of determination of R2  = 0.9904, low limit of detection (0.15 µg/L) and limit of quantification (0.50 µg/L) of bisphenol A, good analyte recoveries (84-120%) and acceptable relative standard deviation (1.8-14.9%, n = 6). The proposed method was successfully applied to three environmental water samples, and bisphenol A was detected in all samples.
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