Flotation-assisted homogeneous liquid–liquid microextraction for determination of thorium in water samples by inductively coupled plasma–mass spectrometry and Box–Behnken design

A fast, simple, and efficient method for extraction, preconcentration, and determination of thorium in water samples with acceptable recoveries based on flotation-assisted homogenous liquid–liquid microextraction combined with inductively coupled plasma–mass spectrometry (ICP-MS) is presented. Various parameters affecting the extraction efficiency were optimized by Box–Behnken design. Under the optimum conditions (concentration of dimethyl vinyl phosphonate = 2.4 × 10^–4 mol/L, pH = 6.5, n-heptane = 150 μL, and acetonitrile = 0.5 mL), the calibration graph was linear in the range of 10.0–400.0 ng/L for thorium. The limit of detection of this method was 2.62 ng/L, and the enrichment factor was estimated to be 136 for thorium.     

Fermentation process of traditional Asokarista using Wickerhamomyces anomalus and its optimization using three-factor,three-level Box–Behnken design

The aim of the study was to determine the effect of selected variables on fermentation of decoction of Saraca asoca bark to develop a suitable method for preparing its polyherbal formulation. S. asoca bark has been fermented using Wickerhamomyces anomalus (nonsaccharomyces yeast) and the method was optimized using response surface methodology (RSM). The independent variables, substrate volume (ml), temperature (°C), and time (hours), were optimized using three-factor, three-level Box–Behnken design to obtain the good content of secoisolariciresinol, lyoniresinol, and 5-methoxy isolariciresinol. Secoisolariciresinol and 5-methoxy isolariciresinol were first isolated from S. asoca bark. The method yielded a quadratic polynomial equation to predict the effect of independent variables on selected responses (<0.0001). All three variables significantly (p-value < 0.0001–0.0068) affected the selected responses. The experimental values agreed closely with the predicted values and the analysis of variance signified a good model fit. The optimum conditions were 67.03 ml substrate volume, 30.95°C, and 64.86 h resulting in 23.24, 21.20, 25.06 μg of secoisolariciresinol, lyoniresinol, and 5-methoxy isolariciresinol content. This is the first report of biotechnological production of Asokarista using W. anomalus in 48 h rather than 35 days as mentioned in traditional method. Also, secoisolariciresinol has been found in fermented S. asoca bark for the first time. It has been ascertained that W. anomalus causes deglycosylation in traditional ayurvedic formulations during fermentation. Present study proved the possibility of using pure strain, Wi. anomalus, for formulating traditional formulation.     

Synthesis of cenosphere supported heterogeneous catalyst and its performance in esterification reaction

A heterogeneous catalyst has been developed from cenosphere, a byproduct generated in thermal power plant. The performance of catalyst was investigated in the esterification of propionic acid and ethanol. The catalyst was characterized by FTIR, X-ray diffraction, field emission scanning electron microscope, and Brunauer–Emmett–Teller surface area and surface acidity analysis. The response surface methodology (RSM) with the Box–Behnken design was employed to design the experiments as well as to optimize the various process parameters such as catalyst loading, alcohol/acid molar ratio, and reaction temperature. The characterization revealed that the cenosphere supported catalyst possessed increased amounts of silica content, surface hydroxyl groups, surface area as well as surface acidity as compared with that of pristine cenosphere. The catalyst showed an excellent activity in the esterification reaction with a maximum conversion up to 91%. The RSM model well fitted the experimental data and predicted optimal conditions which were validated experimentally with a good agreement. The recyclability study showed a significant catalytic stability up to three reaction cycles. This study reveals that the cenosphere supported catalyst can be used as a potential catalyst in the esterification reaction may replace the conventional homogeneous acid catalyst.     

Application of Response Surface Methodology for the Optimization of β-Carotene-Loaded Nanostructured Lipid Carrier from Mixtures of Palm Stearin and Palm Olein

The main purpose of this study was to optimize a β-carotene-loaded nanostructured lipid carrier (βC-NLC) using the lipid matrix of palm stearin and palm olein and Tween 80 as a surfactant. The NLC was prepared by using the high shear homogenization method. Box–Behnken Design (BBD) response surface methodology (RSM) was applied to optimize the process and formulation. A three-factor experimental model was used to optimize the combination of palm stearin ratio (A, %w/w), lipid:surfactant ratio (B, %w/w), and (lipid+surfactant):water ratio (C, %w/w). The formulations were evaluated for their responses on particle size (Y1), polydispersity index (Y2), zeta potential (Y3), and encapsulation efficiency (Y4). Subsequently, Fourier-transform infrared spectroscopy (FTIR), thermal (DT-TGA), x-ray diffraction (XRD), transmission electron microscopy (TEM), and in vitro release (Franz diffusion cell) analyses were utilized to observe the resulting optimum formulation. The optimum formulation was obtained at a combination of A (5.5:4.5), B (1:4.9), and C (24:76) %w/w. This resulted in βC-NLC having a particle size of 166 nm, polydispersity index of 0.35, zeta potential of −26.9 mV, and an encapsulation efficiency of 91.2%. No strong interaction between different NLC components was observed based on FTIR, DT-TGA, and XRD profiles. Round-shaped NLC particles were observed under TEM. Franz diffusion cell observation resulted in diffusion profile of β-carotene of 110.6 μg cm⁻² with a flux of 1.06 (μg cm⁻² hour⁻¹). This indicates that palm stearin and palm olein can be prospectively developed as βC-NLC.     

Role of phase behavior in micronization of lysozyme via a supercritical anti-solvent process

Ultra-fine particles of protein lysozyme were prepared with a supercritical anti-solvent (SAS) apparatus by using dimethyl sulfoxide (DMSO) as solvent and carbon dioxide as anti-solvent. The influences of various experimental factors on the morphology and the mean size of particulate products were investigated. As evidenced from the experimental results, phase behavior of the mixtures in precipitator during the particle formation stage played a crucial role in the SAS processes. Uniform networked nano-particles were obtained when the precipitations were conducted in the supercritical region of carbon dioxide + DMSO mixture. Several different types of morphologies were produced simultaneously as the precipitations were operated near the critical region. Spherical micron-scale clusters were formed in the superheated vapor region, while submicron-particles were aggregated as dense cake when lysozyme precipitated in the vapor–liquid coexistence region. The wide angle X-ray scattering (WAXS) patterns indicated that both the raw lysozyme and the processed particulate samples were amorphous. The differential scanning calorimeter (DSC) thermograms showed that the dehydration peak was disappeared after SAS treatment. Moreover, the networked primary particles could be disintegrated and dispersed well in water through ultrasonication, which were confirmed by analysis with dynamic laser scattering (DLS). A continuous stirred tank reactor (CSTR) model was used to calculate the dynamic composition variations of the mixtures in precipitator during the particle formation period.     

Preparation of liposomes using the supercritical anti-solvent (SAS) process and comparison with a conventional method

Two methods to produce liposomes encapsulating a fluorescent marker were compared: the supercritical anti-solvent (SAS) method and a conventional one (Bangham). Liposome size and encapsulation efficiency were measured to assess the methods. Micronized lecithin produced by the SAS process was characterized in terms of particle size, morphology and residual solvent content in order to investigate the influence of experimental parameters (pressure, CO₂/solvent molar ratio and solute concentration). It appears that when the lecithin concentration increases from 15 to 25 wt.%, at 9 MPa and 308 K, larger (20-60 μm) and less aggregated lecithin particles are formed. As concerns liposomes formed from SAS processed lecithin, size distribution curves are mainly bimodal, spreading in the range of 0.1-100 μm. Liposome encapsulation efficiencies are including between 10 and 20%. As concerns the Bangham method, more dispersed liposomes were formed; encapsulation efficiencies were about 20%, and problems of reproducibility have been raised.     

Application of selective solid-phase extraction using a new core-shell-shell magnetic ion-imprinted polymer for the analysis of ultra-trace mercury in serum of gallstone patients

ABSTRACT

A new ultrasonically assisted spectrophotometric method was developed using stabilized ion polymer on a modified nano-absorbent as a core- shell-shell absorbent (Fe₃O₄@SiO₂@TiO₂–IIP). It has the advantages of further stabilizing the polymer and consequently and much higher efficiency than its conventional adsorbents. The prepared sorbent was characterized and Its parameters were investigated by a Box–Behnken design. The linear dynamic range and limit of detection were 0.20–28.00 µg L^?1 and 0.05 µg L^?1 respectively. In selectivity study, it was founded that imprinting causes increased affinity of the prepared IIP toward Hg²⁺ ion. The proposed IIP is considered to be promising and selective sorbent for solid-phase extraction and preconcentration of Hg²⁺ ion in sera of different types of gallstone patients.     

Development of a Green Process for the Preparation of Antioxidant and Pigment-Enriched Extracts from Winery Solid Wastes Using Response Surface Methodology and Kinetics

Red grape pomace (RGP), an abundant wine industry solid waste, was used for the recovery of polyphenols and anthocyanin pigments, using ultrasound-assisted extraction and water/glycerol mixtures as the solvent. Glycerol concentration (C_gl) and liquid-to-solid ratio (R_L/S) were first optimized by implementing Box?Behnken experimental design and the process was further studied through kinetics. The optimal conditions were found to be C_gl = 90% (w/v) and R_L/S = 90 mL g^?1, and under these conditions the extraction of total polyphenols (TP) and total pigments (TPm) obeyed first-order kinetics. Maximum diffusivity (D_e) values were 4.22 × 10^?12 and 12.59 × 10^?12 m² s^?1, for TP and TPm, respectively, and the corresponding activation energies were (E_a) 13.94 and 8.22 kJ mol^?1.     

Supercritical anti-solvent micronization of marigold-derived lutein dissolved in dichloromethane and ethanol

This work aims to study supercritical anti-solvent (SAS) micronization of lutein derived from marigold flowers. Lutein solution in dichloromethane (DCM) or ethanol was atomized into the stream of supercritical carbon dioxide (SC-CO₂) through a concentric nozzle in a pressurized vessel. The effects of pressure and SC-CO₂ flow rate on morphology, mean particle size (MPS) and particle size distribution (PSD) were investigated. The reduction in lutein MPS from 202.3 μm of unprocessed lutein to 1.58 μm and 902 nm could be achieved by SAS micronization using DCM and ethanol, respectively. In both solvent systems, no significant effects of pressure and SC-CO₂ flow rate on particle morphology were observed. However, pressure was found to have a significant effect on MPS and PSDs of lutein particles.     

Peach-palm (Bactris gasipaes Kunth.) waste as substrate for xylanase production by Trichoderma stromaticum AM7

This work investigated the xylanase production by fungi isolates from tropical agroforestry systems using peach-palm industrial waste as a substrate. Trichoderma stromaticum AM7 was the best xylanase producer and there was a 160% increase in xylanase activity after optimizing by the Box–Behnken statistical design. The optimization process demonstrated that the maximum activity occurred at 0.95% nitrogen concentration after 6 days of cultivation at 32°C, which achieved a yield of 1440?U?g^?1 of dry initial substrate. Analysis by scanning electron microscopy showed degradation of the fibers after cultivation. The optimum pH and temperature for xylanase activity were 5.0 and 50°C, respectively. The extensive degradation of the peach-palm waste and xylanase production by T. stromaticum AM7 was due to the combination of a good physicochemical composition of the culture medium and the characteristics of the selected fungus.     

Box–Behnken response surface method for the synthesis of high-temperature- and salt-resistant filter loss reducers

Wellbores are destabilized by the immersion of a formation in drilling fluid during deep well drilling. To address this issue, in the present study, trimethylolethane triallyl ether (TMETE), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), acrylamide, and N-vinylpyrrolidone undergo free radical copolymerization to produce a PTAAN filter loss reducer. The Box–Behnken response surface method is used to optimize the synthesis of PTAAN; the optimal conditions are 1 wt% TMETE and 0.1111 wt% initiator at 60°C. Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis are used to characterize the composition, micromorphology, and thermal stability of the PTAAN product, respectively. The synthesized product is resistant to high temperatures and salt under the optimal synthesis conditions. It has an API filtration loss of 8.2 mL for freshwater-based mud, an API filtration loss of 13.8 mL for 20% by weight brine mud after aging at 220°C, and an API filtration loss of 29.5 mL at 150°C under high temperatures and pressures. Incorporating PTAAN into the base slurry prevents clay particle agglomeration at elevated temperatures and high mineralization, resulting in a broader clay particle size distribution and ultimately leading to the formation of a thin and compact filter cake.