The aim of this study was to determine the distribution of nitrogen (N)-and phosphorus (P)-based nutrients in the Besut River basin, Malaysia (South China Sea).The mean concentrations of ammonia, nitrate, total dissolved N and total particulate N were 43 µg/L N, 195 µg/L N, 485 µg/L N, 431 µg/L N, respectively.In contrast to N, lower mean concentrations of P were recorded with values of 2.30 µg/L P (dissolved inorganic P), 4.84 µg/L P (total dissolved P) and 8.35 µg/L P (total particulate P).In general, higher concentrations of nutrients were recorded in the middle and lower reaches of the river basin due to human activities.Elevated levels of both forms of nutrients were present during the wet season due to terrestrial run-off to the water column.The molar ratio of dissolved inorganic N:P (nitrate + ammonia: inorganic P) was extremely high (72:1), much higher than the Redfield ratio (16:1), suggesting the nutrient-limiting factor for phytoplankton growth in this river basin was P. The results from this study can be used as a baseline comparison for future monitoring of this river basin.
A rise of 2 o C in the Earth's temperature is likely to occur when the concentration of carbon dioxide (CO 2 ) in the atmosphere reaches approximately 450 ppm.CO 2 emissions are closely related to the continual use of fossil fuels.In order to make fossil fuels sustainable, carbon capture and storage (CCS) is required to reduce CO 2 emissions.CO 2 hydrate (CO 2 :6H 2 O) formation has been investigated as a way to capture CO 2 .The formation of hydrate in this work was experimentally investigated in batch mode inside a vertical fixed-bed reactor (FBR), also known as high-pressure volumetric analyser (HPVA).Standard silica gel with an average particle size of 200-500 µm, mean pore size of 5.14 nm, a pore volume of 0.64 cm 3 /g, and a surface area of 499 m 2 /g was used as a porous medium.The presence of hydrate in FBR was justified by using graphic methods.The solubility of CO 2 in water using Henry's law and the experimental pressure-time (P-t) curve were analysed to determine the formation of hydrate.Hydrate formation was confirmed when the mole fraction of CO 2 dissolved in water exceeded the Henry's law value as well as a two-stage pressure drop in the experimental P-t curve.
Sediment core samples obtained from the Port of Sedili and Tanjung Pelepas, Johor were slice into layers with intervals of 3 cm to estimate the contamination levels of rare earth elements at harbour areas.An analysis of rare earth elements (REEs) including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu were conducted using the Inductively Couple Plasma Mass Spectrometry.The measured concentration of REEs normalized with Fe as an enrichment factors signal.A positive value ratio of Ce/Ce* anomalies (1.10 -1.18) was shown at the Port of Sedili whereas at the Port of Tanjung Pelepas showed negative Ce/Ce* anomaly values (0.87 -0.96).However, both stations showed weak positive Eu/Eu* anomaly values of 0.76 -0.84 (Port of Sedili) and 0.96 -1.0 (Port of Tanjung Pelepas).Fractionation index was also using to define the relative behaviour of LREEs to HREEs by the ratio of La/Yb n .The results of this study support the proposition to use REEs as an indicator of pollution.
Microwave-assisted aqueous enzymatic extraction (MAAEE) is a promising green technology that is fast, efficient and energy saving. The physicochemical parameters and fatty acids composition of the MAAEE-extracted oil were reportedly quite comparable with those of solvent-extracted oil and control oil, showing no significant differences (p> 0.05) among the extraction methods. However, the oxidative stability of the MAAEE obtained oil was found to be considerably improved in the comparison as evident by the determinations of chemical profile values. Moreover, the microwave-enzymatic adjuvant improved the oil extraction yield as well as the oxidation properties of the oil produced without altering its other quality attributes. The present work compared the quality characteristics of microwave-assisted aqueous enzymatic extracted Elateriospermum tapos seed oil with those of hexane-extracted oil and control oil. Interestingly, MAAEE process has achieved 12% and 16% higher extraction efficiency and concentrated omega-3 fatty acid, respectively compared to non-enzymatic microwave-assisted extraction (MAE). Although resulted in lower yield than hexane-extraction (Soxhlet), MAAEE extracted 24% higher concentrated omega-3 fatty acid with almost 99% removal of anti-nutrient amygdalin within 75 seconds. Hence the study on the interaction of extraction parameters as well as the MAAEE optimization process is sustainably feasible. Keyword: microwave assisted aqueous enzymatic extraction, seed oils, Elateriospermum tapos, amygdalin Abstrak Pengekstrakan enzim berakues yang dibantu dengan gelombang mikro (MAAEE) adalah teknologi hijau yang menjanjikan proses yang pantas, cekap dan penjimatan tenaga. Parameter fizikokimia dan komposisi asid lemak daripada minyak yang diekstrak MAAEE dilaporkan setara berbanding dengan minyak ekstrak-pelarut dan minyak kawalan serta tidak menunjukkan perbezaan ketara (p> 0.05) di antara kaedah pengekstrakan. Walau bagaimanapun, kestabilan oksidatif minyak MAAEE didapati lebih baik dalam perbandingan seperti yang ditunjukkan oleh penentuan nilai-nilai profil kimia. Tambahan pula, adjuvan gelombang mikro-berenzim meningkatkan hasil pengeluaran minyak serta ciri pengoksidaan minyak yang dihasilkan tanpa mengubah sifat-sifat kualiti yang lain. Kajian ini membandingkan ciri-ciri kualiti minyak biji Elateriospermum tapos secara kaedah pengekstrakan enzim berakues-berbantu gelombang mikro dengan minyak ekstrak-pelarut heksana dan minyak kawalan. Menariknya, proses MAAEE telah masing-masing mencapai kecekapan pengekstrakan 12% dan kepekatan asid lemak omega-3 16% lebih tinggi berbanding pengekstrakan berbantu gelombang mikro tanpa berenzim (MAE). Walaupun hasilan lebih rendah daripada pengekstrakan heksana (Soxhlet), MAAEE memperoleh asid lemak omega-3 berkepekatan 24% lebih tinggi dengan hampir 99% penyingkiran amigdalin anti-nutrien dalam 75 saat. Oleh itu, kajian mengenai interaksi parameter pengekstrakan serta proses pengoptimuman MAAEE menunjukkan kewajaran secara lestari. Kata kunci: pengekstrakan enzim berakues dibantu gelombang mikro, minyak bijian, Elateriospermum tapos, amigdalin ISSN 1394 2506 Azlan & Ida Idayu: GREEN MICROWAVE-ASSISTED AQUEOUS ENZYMATIC EXTRACTION OF Elateriospermum tapos SEED OILS 489 Introduction Microwave uses electromagnetic wave which penetrates certain materials to provide volumetric heating through ionic conduction and dipole rotation [1]. Water and aqueous based solvent system offer an increasingly crucial choice for the replacement of conventional organic solvent [2]. Therefore, the microwave assisted aqueous enzymatic extraction (MAAEE) method is a highly potential, green, fast, efficient and energy saving method which eliminates the disadvantages of conventional solvent extraction method with undesirable effect on oil quality. Moreover, the treatment of seeds with enzymes enhances the extraction of oil yield due to its hydrolyzed structural polysaccharide of the cell walls and proteins associated with the lipid bodies [3]. MAAEE had been applied for oil extraction from seed crops such as pumpkin seed [3] and Forsythia suspense seed [2]. Omega-3 fatty acid is an essential fatty acid that need to be consumed through supplements or food products due to the incapability of human body to generate the compound naturally by itself [4]. Perah or scientifically known as Elateriospermum tapos seed (ETS) is an underutilized Malaysia local plant seed that had been reported to be rich of omega-3 fatty acid (Figure 1). A research by Yong and Salimon [5] claimed that ETS contains 17.4% of alpha linolenic acid (ALA) (PubChem CID: 5280934). The current work applies MAAEE for extraction of ETS oil, quantification of the specific amount of omega-3 fatty acid concentration and its anti-nutrient, amygdalin. Figure 1. Properties and molecular structure of omega-3 fatty acid [6]. Materials and Methods Plant materials Elateriospermum tapos seed (ETS) was obtained at a local farm in Kuala Lipis, Pahang, Malaysia and was botanically identified by Biodiversity Unit, Institute of Bioscience, University Putra Malaysia (specimen voucher number SK2782/15). The seeds were manually cleaned and flooded with tap water to separate the extraneous matters (dust, vain seeds and straw from threshed seeds). The shells were removed; cleaned seeds were grinded using a laboratory grinder (MX-898M Panasonic, Malaysia) and sieved (Retsch siever, Germany) to a desired particle size and then stored at -20 °C in airtight bags until further use. The moisture content of the seeds, which were 6-7%, was determined using the infrared moisture analyser (FD-620 Kett, Japan). Reagents Cellulase from Aspergillus niger (Tokyo Chemical Industry), pectinase from Aspergillus niger (1.02U/mg) and proteinase from Aspergillus melleus (≥3 units/mg solid) from Sigma Aldrich, hexane analytical and GC grade from Qrec and Merck, Malaysia. Extraction process For Soxhlet extraction (SE) process, 5 g of ETS (0.5 mm particle sizes) were placed into each thimble and 150 mL hexane was used as a solvent. This process was carried out by refluxing each sample for 6 hours on a heating mantle. After the elapsed time, a rotary evaporator was used to evaporate the solvents. The SE extraction produced Malaysian Journal of Analytical Sciences, Vol 23 No 3 (2019): 488 494 DOI: https://doi.org/10.17576/mjas-2019-2303-13 490 48.99±0.79% of oil, which was set at 100% oil recovery in the comparison with the MAAEE in this study. Next, the samples were collected and preserved at -20 °C in sealed bottles for further analysis. For MAAEE method, a domestic microwave oven system was used (Sharp Model R-397J, Malaysia) equipped with digital control system for irradiation time and irradiation microwave power (110 W, 330W, 550 W, 770 W and 1100 W) and operates at 2.4 GHz. A mode stirring table was also included in microwave system to dissipate the microwave energy during microwave heating which is facilitate the extraction sample to heat up homogeneously. Subsequently, 5 g of grinded ETS and enzyme cocktail (cellulose: pectinase: proteinase ) ratios of 1.4:1.7:1.4 were accurately weighed and placed into a 250 mL flask with 1:5 solid to solvent ratio (based on preliminary experiment). Subsequently, the MAAEE extraction was conducted according to the design of experiment (DOE) at the following conditions; 110-1100 W irradiation power, 30-120 s extraction time, 1-5% enzyme cocktail concentration and 0.5-1.5 mm particle size with a total of 30 experiment runs. After extraction, the solution obtained from MAAEE was then centrifuged at 10000 rpm speed for 15 minutes, and oil phase was withdrawn using a micropipette. The oil was then weighed, and the extraction yield was expressed as the mass percentage ratio (oil extracted /total oil obtained by SE method, %) which result an optimal oil extraction yield of 46.12±1.48% at 110 W microwave power, 30 s extraction time, 1% enzyme cocktail concentration and 0.5 mm particle size (based on previous study). Next, the samples were collected and preserved at -20 °C in sealed bottles for further analysis. Identification and quantification of omega-3 fatty acid concentration The extracted ETS oil was converted to fatty acids methyl ester (FAMEs) prior to injection. About 1 μL of the sample was injected into GC (model Perkin Elmer Auto System XL) to analyze the omega-3 fatty acid. It was equipped with flame ionization detector and BPX 90 capillary column (60 m x 0.25 mm x 0.55 μm). The detector temperature and injector temperature were programmed at 250 °C. The oven temperature program was set at the initial 100 °C followed by ramp 1 at 20.0 °C /min to 170 °C, hold for 0.00 min, ramp 2 at 10.0 °C/min to 230 °C , hold for 7 minutes and ramp 3 at 30 °C/min to 250 °C, hold for 2 minutes. Nitrogen was used as the carrier gas. Subsequently, the peaks detected by the retention time were identified by comparing the result produced with standards under the same condition. Different concentrations (100, 200, 300, 400, 500, 600, 700, 800, 900 and 1000 ppm) had been prepared from omega-3 fatty acid (alpha linolenic acid) standard (Sigma Aldrich, Germany). The standards were injected in GC using the same condition of fatty acids analysis. The calibration curve of absorbance versus concentration graph was plotted. The concentration of extracted omega-3 was determined in mg of ω-3/g of oil using equation 1. Cω−3 = [C ×V] Woil (1) Cω-3 indicates the concentration of the extracted omega-3, mg of ω-3/g of oil; C indicates the concentration of omega-3 obtained from calibration curve, mg/mL; V indicates the volume of omega-3 fatty acid solution, mL and Woil is the weight of the extracted oil, g. FTIR analysis The chemical structure of ETS oil extracted by MAAEE, MAE and SE were determined by FTIR spectrometer (Perkin-Elmer Spectrum One) equipped with a deuterated triglycine sulphate (DTGS) as a detector and a KBr/ Germanium as a beam splitter. A fe
In this study, low grade limestone (LGL) was used in treating acid mine drainage (AMD).Based on X-ray fluorescence (XRF) result, the content of calcium carbonate mineral in limestone used was around 80% that can be considered as LGL.The pH of AMD samples increased after treated with all parameter weights of LGL at every five minutes of interval times.The parameters weights of LGL used in the experiments were 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 g.For every parameter weight of LGL, the interval times used were 0, 5, 15, 20, 25 and 30 minutes.The highest of pH value obtained was 6.44 ± 0.00 by using 6.0 g of LGL at interval time 30 minutes.The suitable pH value chosen was 6.11 ± 0.00 by using 5.0 g of LGL at interval time 20 minutes because the parameter had complied with Standards A and B of Environmental Quality Act 1974 with less cost compared to other parameters.Heavy metals content such as arsenic, cadmium, chromium, iron, manganese and zinc had decreased after reaction with all LGL weights.The content of arsenic in AMD samples after reaction with all LGL weights had complied with both standards' requirement except with 1.0 g of LGL.The percentage of removal heavy metals by using all parameter weights of LGL such as arsenic, cadmium, chromium, iron, manganese and zinc were around 98.8 to 99. 8%, 53.8 to 88.5%, 94.7 to 96.5%, 99.6 to 100%, 34.6 to 38.9% and 27.0 to 90.1%, respectively.
Presently, canned bamboo shoots in Yanang (Tiliacora triandra (Colebr.)Diels) leaf extract is produced in order to expand shelf-life and ease to prepare food.The objectives of this research were to investigate the effect of different thermal processing during Yanang leaf extract preparation on total phenolic content, DPPH radical scavenging and xanthine oxidase inhibitory activities and to determine kinetics of the extract's quality alterations.The preparation included 1:12 (w/v) leaves to water ratio, 32,000 rpm blending speed and different heating temperature at 60, 70 or 80 o C for 15 minutes.Data were collected at 0, 1, 3, 6, 9, 12 and 15 minutes of heating time.The results showed that fresh Yanang leaf extract had total phenolic content of 680.16 ± 19.57mg GAE/100 mg db. and it possessed DPPH radical scavenging and xanthine oxidase inhibitory activities at 163.53 ± 0.87 µg BHT/mL and 78.58 ± 0.17%, respectively.The results revealed that an increase in heating temperature and time decreased total phenolic content and the DPPH radical scavenging and xanthine oxidase inhibitory activities of Yanang leaf extract.During 15 minutes heating, the total phenolic content of Yanang leaf extract ranged from 526.33 ± 28.79 to 638.93 ± 29.69 mg GAE/100 mg db., DPPH radical scavenging activity ranged from 92.86 ± 1.66 to 136.41 ± 5.70 µg BHT/mL and xanthine oxidase inhibitory activity ranged from 72.64 ± 0.34 to 76.65 ± 0.50%.The change of total phenolic content (R 2 = 0.809-0.959)followed zero-order kinetic model and that of DPPH radical scavenging activity (R 2 =0.783-0.920)while xanthine oxidase inhibitory activity (R 2 = 0.864-0.922)followed second-order kinetic model.
Lipase from Candida rugosa was immobilized onto diethylaminoethyl-cellulose (DEAE) through physical adsorption method with high percentage of protein absorption obtained at 84%.The lipase-DEAE was used to catalyze the enzymatic esterification of butyl oleate by reacting oleic acid and butanol in hexane.Butyl oleate, an alkylic ester of long-chain fatty acid is now in high demand to produce biodiesel.The effect of reaction temperature, thermostability of the immobilization lipase, stability in organic solvent, leaching with hexane and storage studies under various conditions of immobilized lipase were investigated.The optimum esterification was found to be up to 90% yield.Only a slight of lipase leached out after being washed by 20 mL of hexane.This showed that lipases were strongly attached to the DEAE support via physical adsorption method, and it could be used as industrial biocatalyst.
In this work, the magnetite-reduced graphene oxide (Fe 3 O 4 /rGO) was fabricated for a selective voltammetric detection of uric acid.The magnetite-reduced graphene oxide is biocompatible sensing material that was synthesized through one-step reaction mechanism.The attachment of spherical like Fe 3 O 4 particle on the rGO sheet was characterized by Fourier Transform Infrared (FTIR), Ultraviolet-Visible Spectroscopy (UV-Vis) and Scanning Electron Microscopy (SEM).The electrochemical performance of the Fe 3 O 4 /rGO/GCE electrode were studied by Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV).The superparamagtism property of the Fe 3 O 4 anchoring on the rGO sheet provides a conduction pathway for the analyte diffusion meanwhile promote the electron transfer kinetic between the electroactive species and electrode surface.The enhanced current response signal produced from the reduction-oxidation process by the electroactive species were optimized further in parameters of scan rate, concentration of uric acid and pH value of the supporting electrolyte.The observed DPV response displays a linearity relationship on uric acid concentration ranging from 4 μM to 100 μM with correlation coefficient 0.989 and a sensitivity of 0.08478 μA/μM.The detection limit and limit of quantitation were found to be 3.04 μM and 10.14 μM respectively.
Hydroxamic acids, RCONHOH, are electronically flexible compounds for organic and inorganic analyses due to their more delicate structures compared to carboxylic acid.These acids are easy to deprotonate to produce hydroxamate ions.The syntheses, physico-chemical and characterization of benzohydroxamic acid (BHA) and methylbenzohydroxamic acid (CH 3 -BHA) and their metal complexes VO(IV), Cr(III) and Ni(II) are reported herein.The metal complexes were synthesized by condensation reaction of BHA and CH 3 -BHA with metal salts in 2:1 molar ratio.The compounds were characterized by elemental analysis, infrared spectroscopy (IR), 1 H and 13 C NMR, UV-Vis, TGA, magnetic susceptibility and molar conductance.From IR and magnetic susceptibility data, each complex is coordinated to the metal via oxygen and oxygen (O,O) in bidentate manner.The geometry of all metal complexes is octahedral except for [VO(BHA) 2 ] that is square-pyramidal.The molar conductance values suggested that all complexes are non-electrolytic.A cytotoxicity study against human colorectal cancer, HCT116 cell lines, revealed that all the complexes are better anticancer agents than their parent ligands.
Determining the shooter is an important element during investigation of firearm related offences, particularly through the detection of gunshot residue (GSR) as forensic evidence on shooter's hand.However, such detection could be restrained if it is obstructed by the wearing of gloves by a shooter.Hence, it is worth investigating the presence of GSR on gloves, aiming to suggest an individual's contact with a weapon.In this study, Modified Griess Reagent (MGT) commonly available in forensic laboratory was utilised to screen GSR on individual gloves of different materials worn by a shooter during a shooting training session.The experimental results revealed that both the palm and back of gloves equally allows the detection of GSR by MGT (p = 0.083).No statistically significant association was evident between the types of gloves and positive indication of MGT (p = 0.122).The types of firearms, neither revolver nor semi-automatic pistol showed significant association with the detection of GSR on the gloves (p = 0.248).When two-hand shooting was performed, glove samples worn on left and right hands gave almost similar testing results (p = 0.626).Although the presence of GSR on a glove after a shooting could be relatively low, the study has demonstrated that applying MGT, a simple test could assist crime scene investigation in determining the presence of GSR, in cases when gloves were used.
The inclusion complexation behaviour of bisphenol A (BPA) into hydrophobic cavity of β-cyclodextrin (β-CD) was investigated by using 1 H NMR spectroscopy in deuterium oxide by varying the molar ratios between β-CD and BPA from 1:0 to 1:2.The ideal molar ratio for the β-CD:BPA complex was determined as 1:1.In addition, the inclusion of BPA into β-CD produced significant changes in the chemical shifts of H5 and H3 protons, which were located inside the cavity of cyclodextrin.On the other hand, the H2, H4 and H6 protons that were located at the exterior surface of β-CD did not result in any significant changes in the chemical shift, and thus confirmed the formation of the β-CD:BPA inclusion complex.The observed chemical shifts of H5 and H3 protons, when BPA interacted with the β-CD cavity, were utilised to determine the binding association constant (K a ) and maximum chemical shift difference (∆ max ).From the nonlinear calculation, the K a for H3 proton, i.e. 4.10 x 10 3 M -1 , was shown to be stronger than that of H5, i.e. 3.62 x 10 3 M -1 .However, the H5 proton gave a higher ∆ max than the H3 proton, which were 0.1412 ppm and 0.0573 ppm, respectively.
Malachite green is widely used in the aquaculture, food, and textile industries.However, malachite green is carcinogenic, mutagenic, and teratogenic.Therefore, a chemical sensor was developed to detect malachite green in water samples.Screenprinted carbon electrode was coated with (p(AAm-co-EMA)/Ru(bpy) 3 2+/AgNWs to investigate its potential as a membrane for chemical sensor.The membrane was synthesized using the photopolymerization technique and characterized by fourier transform infrared (FTIR), 1 H nuclear magnetic resonance ( 1 H NMR), swelling test, field emission scanning electron microscopy/electron dispersive X-ray analysis (FESEM/EDX), thermogravimetric analysis (TGA), and cyclic voltammetry (CV).The peak of -CO in the FTIR spectra indicated that the copolymerization was successful.Furthermore, the NMR spectrum confirmed the FTIR result with the presence of peak at 4.2 ppm.Swelling test showed that p(AAm-co-EMA)/AgNWs had a lower swelling percentage than p(AAm-co-EMA) due to AgNWs filling the pores of the membrane, which can be seen in the cross section of the SEM micrograph.Thermal decomposition temperature of the membrane was around 400 °C.Cyclic voltammogram proved that the p(AAm-co-EMA)/Ru(bpy) 3 2+/ AgNWs film coated on screen-printed carbon electrode which acted as a working electrode was able to detect malachite green by showing anodic peak around 0.25 V and cathodic peak around -1.0 V.
Mesoporous silica is material that possesses the pore sizes between 2 nm to 50 nm which had expanded their applications rapidly.In this study, mesostructured SBA-15 was synthesized and characterized then the electrochemical behaviour being analysed to determine the current signal and the impedance of mesoporous silica carbon electrode.The material with pore sizes 5.5 nm was successfully synthesized by surfactant templating technique, using triblock copolymer pluronic (P123) as directing agent and tetraethyl orthosilicate (TEOS) as silica sources.The synthesized SBA-15 was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), nitrogen adsorption-desorption and infra-red (IR).Two different electrodes were fabricated which carbon paste electrode (CPE) and hybrid SBA-15 with carbon paste electrode (SBA-15/MCPE) and analysed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).The SBA-15/MCPE results better adsorption and enhanced the response signal to 30% and lower resistance compared to CPE with 179Ω and 187Ω respectively due to addition of meso-sites which improved the electron pathway This study demonstrates that mesoporous silica (SBA-15) can be considered as promising material in development of high performance, lightweight and flexible devices in electrochemistry.
Perovskites are materials that have many potential applications, such as humidity sensors, transparent conductive oxides, photocatalysts and capacitors.Strontium stannate (SrSnO 3 ) is a perovskite semi-conductor material with a wide band gap.Several synthesis methods are commonly used to form SrSnO 3 , including solid-state reaction (SSR), sol-gel and hydrothermal.The SSR method requires high temperature calcination.On the other hand, sol-gel and hydrothermal methods merely need a lower calcination temperature to form perovskite materials.The sol-gel methods were done by adding a surfactant to Sr(NO 3 ) 2 and SnCl 2 solution in water before calcination.The autoclave approach was used in the hydrothermal method prior to calcination to form SrSnO 3 .The objective of this study was to determine the morphological and optical properties of SrSnO 3 synthesized by sol-gel, hydrothermal and SSR.The band gap was calculated via Kubelka-Munk relations and were found to be 4.05 eV (hydrothermal), 5.50 eV (sol-gel) and 3.95 eV (SSR).Sol-gel methods showed the widest band gap for SrSnO 3 .Optical results showed that there is a difference in terms of band gap for a perovskite synthesized by the different methods.Mass reduction analysis by TGA showed a sol-gel has mass loss of approximately 58% due to dehydration, which is more than for hydrothermally synthesized SrSnO 3 .This reduction is higher than for SrSnO 3 synthesized by hydrothermal method.It was observed that different synthesis methods impact the optical properties and morphology of SrSnO 3 powders.
An analytical Quality by Design(AQbD) oriented ultra-fast liquid chromatography method was developed for quantification of sertaconazole nitrate in pharmaceutical dosage form.A central composite design (CCD) was employed to establish optimum chromatographic conditions ensuring method robustness by selecting methanol (%) and flow rate (mL/min) as the factors, to study their effect on the system suitability parameters such as retention time, plate number and tailing factor as the response variable.Further, the method was carried out with design of experiments (DoE) optimized chromatographic conditions.The intermediate precision of the method was studied using a full factorial design (FFD) considering the number of days and analysts as the variables.The chromatographic separation was achieved on a phenyl-hexyl column using methanol: water (92:8, %v/v) as the mobile phase at a flow rate of 1.3 mL/min and photo diode array detection at 260 nm.The values obtained for validation parameters were within the acceptance limit.The method was linear over 5-100 µg/mL of sertaconazole.Analysis of the system suitability suggested a high degree of method reproducibility and robustness.In a nutshell, the method was found to be highly suitable for its applicability in the determination of sertaconazole in bulk and tablet dosage form.
Ferrocene is an orthodox organometallic complex.This "sandwich compound" was found to have great flexibility in chemical reactions.The use of ferrocenyl derivatives branches into various interesting fields especially for biological applications.Derivatives of ferrocenylamides are of great interest in the field of medicine and biology researches, due to their ability to bind with various biomolecules, i.e.DNA.Thus, a simple yet effective method in the formation of ferrocenylamide derivatives is desirable.Ferrocene is stable in both aqueous and aerobic media, it also has a certain degree of resistance to thermal degradation, and hence the synthesis of ferrocenyl derivatives via carbodiimide coupling is possible.In this work, N-analineferrocenylamide was synthesised from 3-(ethyliminomethyleneamino)-N,N-dimethylpropan-1-amine (EDC) coupling of ferrocenecarboxylic acid and p-phenylenediamine.This synthesis approach is a simple and easy one-pot reaction without the need of tedious conditions and has a good product yield.
An optical pH sensor based on the immobilisation of curcumin in sol-gel/chitosan hybrid thin films was fabricated on a cellulose acetate sheet as solid support for preparing a thin film.The thin film was prepared using the dip coating method.This sensor gave a range of linear pH responses at pH 9-13 (R 2 = 0.9821).The relative standard deviation (RSD) values of repeatability of this sensor were 7.03% (pH 10) and 3.34% (pH 11), while the RSD values of reproducibility were 7.46% (pH 10) and 8.66% (pH 11).The photostability of immobilised curcumin gave an RSD value of 2.37% for a study period of 15 weeks.This sensor had a response time between 10-20 s, and no hysteresis effect was observed when the pH in a cycle of pH 2-12-2 was measured.This sensor was applied in the determination of pH in real samples, and the results were comparable to a conventional pH meter.
This paper reports the synthesis of two tetradentate Schiff bases namely 2,2'-(((2,2-dimethylpropane-1,3-diyl) bis(azanylylidene))bis(methanylylidene))bis(4-methoxylphenol), LM, and 2,2'-(((2,2-dimethylpropane-1,3-diyl)bis (azanylylidene))bis(methanylylidene))bis(4-nitrophenol), LN.The Schiff bases were reacted with palladium(II) acetate in 1:1 molar ratio yielding two palladium(II) complexes, PdLN and PdLM.The compounds were characterized through elemental analysis, infrared spectroscopy, 1 H and 13 C Nuclear Magnetic Resonance (NMR), magnetic susceptibility, molar conductivity and melting point.Complexation was indicated to have occurred by the shifting of the characteristic (C=N), (C-O) and (HC=N) peaks.This was supported by appearance of new peaks of (M-N) and (M-O) as well as disappearance of (O-H) peak on the IR and 1 H NMR spectra of the palladium(II) complexes.The diamagnetic and non-electrolytic nature of the complexes suggested square planar d 8 palladium(II) geometry and absence of counter ions, respectively.The catalytic activity of the palladium(II) complexes was investigated for copper-free Sonogashira reaction between iodobenzene and phenylacetylene in dimethylsulfoxide (DMSO) at 80 o C, 100 o C and 140 o C. The conversion of iodobenzene at 12 h reaction time was monitored by GC-FID.At 100 o C, the most active catalyst was PdLN, indicating that the electron withdrawing substituent -NO 2 , has the ability to enhance catalytic properties of the complexes.At 140 o C, both palladium(II) complexes successfully converted 100% of iodobenzene.
Conductive polymer composite (CPC) has been used on bipolar plates by compression and injection molding methods.The CPC material comprises 25% polypropylene and 75%graphite with size variation (40, 100, 150, and 200 µm) according to particle size dispersion test.The composite is mixed using an internal mixer to obtain a homogeneous mixture at a process temperature of 200 °C.Electrical conductivity tests are performed on each particle size composition.The highest electrical conductivity produced by compression and injection molding methods is 17 and 12 S/cm, respectively.These values are both obtained on a 40 μm graphite filler.Results show that the type of manufacturing process affects the value of electrical conductivity using the same material.
Nanofiber materials have often been reported as transporters for clinical drugs but face the limitation of burst releasing the drugs.Therefore, mesoporous silica nanoparticles (MSNs) have raised much interest to be used in drug delivery system because of their large pore volume and high surface area.In this study, nanofiber drug delivery system based on poly(vinyl alcohol) (PVA) loaded with novel ionic liquid templated MSNs were successfully prepared by the electrospinning method.The composite fiber mat was designed for the prolonged and sustained release of drug.MSNs were synthesized by co-condensation method with average particles size of ~70 nm and then loaded with hydrophilic model drug methylene blue (MB).The effect incorporation of MB-loaded MSNs into the polymer solution to form fibrous structure was investigated.Uniform PVA/MB nanofiber mat was also produced as controls.The morphologies of nanoparticles and composite nanofiber were characterized by field emission scanning electron microscope (FESEM).After electrospinning, electron microscope revealed that MSNs were randomly distributed in the regions of nanofiber.Drug release profiles of MB from MSNs and electrospun mats were evaluated.The results indicated that adsorption of model drug MB into MSNs and incorporation them into nanofiber are effective way of minimizing burst release of drug.Sustained delivery was achieved with controllable release during the 120h releasing period
