Face-centered Composite Design Research Articles

An Experimentally Designed Sertaconazole Sensor for Selective and Enhanced Potentiometric Response: Determination in Cream, Plasma & in Presence of Other Imidazoles

AbstractA two‐step experimental design was followed to develop a potentiometric solid contact ion‐selective electrode for sertaconazole (STN) determination. A full factorial design was first employed in screening for the best cation exchanger, ionophore and conducting polymer. Amounts of the selected cation exchanger; tetrakis[3,5‐bis(trifluoromethyl)phenyl] borate (TFPB), and ionophore; calix[6]arene (CX6), incorporated in STN sensing membrane were then optimized with the aid of face centered composite design. Calibration slope, detection limit and electrode selectivity in presence of another imidazole‐classified drug; econazole, were the selected responses in both designs. The optimized ion‐sensing membrane, containing 1.0 mg TFPB and 9.9 mg CX6, showed enhanced responses compared to the primarily screened ones. This optimized electrode exhibited a linear response over a concentration range of 1.0×10−6‐−1.0×10−3 M with a Nernstian slope of 57.50 mV/decade. The detection limit was lowered by about one order of magnitude via this optimization to equal 3.16×10−7 M. The proposed electrode was successfully challenged for STN determination in the presence of other imidazoles. It was then used for STN determination in cream and spiked plasma as an example of biological fluid. Our proposed potentiometric method was finally compared to the reported chromatographic ones in terms of sensitivity, and greenness evaluation by the widely applicable Analytical GREEnness (AGREE) tool. The comparison revealed the superiority of our method in terms of sensitivity and sustainability.

Green synthesis of biodiesel from magnetic basic biochar derived from Amazonian murici residual biomass: Optimization, kinetic, thermodynamic, and environmental studies

There is a growing need for sustainable catalysts in biodiesel production, however, efficient and low-cost alternatives derived from agro-industrial residues remain limited. This study addresses this gap by exploring murici biochar as a potential source for catalytic development. A basic magnetic catalyst, based on biochar from an Amazonian agro-industrial residue and consisting of sodium impregnated in murici biochar with cobalt ferrite as the magnetic phase, was produced for application in the transesterification reaction of soybean oil. The catalyst was synthesized by wet impregnation with different sodium concentrations to determine the optimal concentration of active phase in the synthesis process. The catalyst demonstrated the best performance and was characterized by TGA, XRD, FT-IR, SEM, EDS, and VSM. A central face-centered composite design was used in the development of a mathematical model for the prediction of ester content. The biodiesel obtained in the optimized reaction conditions of temperature of 90 °C, reaction time of 1.4h, methanol:oil (MeOH:oil) molar ratio of 17:1, and catalyst concentration of 7% obtained ester content of 97.11% and presented physicochemical properties according to the limits established in the ASTM D6751. Moreover, the kinetic and thermodynamic studies revealed that the process follows the pseudo-first order. It also presents an endothermic and not spontaneous character. The green reaction parameters indicate that the reaction using the catalyst is sustainable with low waste generation. Thus, this study show the feasibility of applying the agro-industrial residue in the synthesis of environmentally friendly and low-cost magnetic basic catalysts for the production of biodiesel.

Green RP-HPLC methods for assay and related substances in rivaroxaban tablets

AbstractIn this study, two different ethanol-based RP-HPLC methods for assay and quantification of rivaroxaban related substances in tablets were developed, based on green analytical chemistry (GAC) principles, using the design of experiments approach. The chromatographic separation was performed on X-Bridge C18 column (250 × 4.6 mm, 5 µm particle size), using isocratic elution with ethanol : water (35:65, % v/v) for the assay and gradient elution with ethanol/water mobile phase, for related substances, with a flow rate of 1.0 mL min−1. The gradient method was optimized for the separation of three specified impurities (impurity G, impurity H, and impurity 14) and the selectivity was further confirmed using forced degradation studies. Both methods were validated in accordance with ICH guidelines. The robustness of the methods was confirmed with the Central Composite Face Design of Experiments. Analytical Eco-scale approach and AGREE metrics confirmed that both methods are in accordance with the GAC principles. The proposed ethanol-based RP-HPLC methods were applied for assay and determination of related substances in rivaroxaban 10 mg tablets obtained from three different manufacturers available on the Macedonian market.

Optimization of direct smelting for mercury-free gold recovery in artisanal and small-scale gold mining

Artisanal and small-scale gold mining (ASGM) faces challenges in accessing capital, technology, and responsible practices, hindering sustainable operations and contributing to environmental and health impacts from mercury use. This study evaluated optimizing direct smelting of gold concentrates as an alternative to mercury amalgamation for efficient and responsible production. 50 kg of ore from Nholi mine was concentrated using a Knelson concentrator and analyzed (XRF, fire assay with AAS, XRD). Response surface methodology with a face-centered composite design investigated smelting temperature (1100–1400 °C), duration (30–90 min), and concentrates-to-flux ratio (1:1–3:1) effects. The impact of sulfide concentration (pyrite varied 6.7–48%) on gold recovery was explored. Low-sulfide concentrates associated with pyrite and sphalerite yielded best recovery (>80%) at 1250 °C for 90 min with 2:1 concentrates-to-flux ratio. Direct smelting with ≤6.7% sulfide enabled over 87% gold recovery, facilitating responsible ASGM production.

Multi-objective optimization and performance improvement of CD nozzle design parameters for cold spray coating process using RSM, ANN and GA

This study presents the multi-objective optimization of the convergent-divergent (CD) nozzle for the cold spray (CS) process and investigates the impact of five key nozzle design parameters. A 2D axisymmetric baseline nozzle was optimized through face central composite design (FCCD), computational fluid dynamics (CFD) simulations, response surface methodology (RSM), artificial neural networks (ANN), and genetic algorithms (GA). The nozzle performance in the CS process advances the manufacturing technologies by significantly optimizing the four response variables. Comparative analysis shows that RSM models (R² = 0.9893) were more accurate on average than ANN models (R² = 0.9848), although ANN provided a deeper understanding of complex interactions with an overall correlation coefficient of 0.99191. Sensitivity analysis suggested that increasing convergent length (Lc) increases particle velocity (PV) before it stabilizes while particle temperature (PT) decreases due to cooling effects. Divergent length (Ld) increases PV to an optimal range, but reduces PT, indicating energy loss. Smaller injector inner diameter (Did) enhances PV but reduces PT. Injector length (Li) increases PV to a certain limit, beyond which benefits stabilizes, and also increases surface pressure (SP). Expanding the exit diameter (De) increases PV, drops PT and heat flux (HF), and reduces SP, indicating decreased flow resistance. Optimization with RSM coupled with numerical simulation (RSM-DF) improved PV, PT, HF, and SP by 9.1 %, 4.4 %, 17.9 %, and 27.6 % respectively. Further optimization with a 5–6–4 ANN and GA (NSGA-II) improved PV by 5 %, PT by 5.4 %, HF by 15.7 %, and reduced SP by 20.9 %. Integrating CFD, RSM, ANN, and GA provides an effective approach for optimizing CD nozzle parameters.

Optimization of gluten-free cake formulation by replacement of rice flour and baking powder with different levels of eggshell powder using response surface methodology

AbstractThe shell and membrane of the egg constitute approximately 11% of the whole egg and is an important food industry waste. Eggshells can be used as an additional source of calcium to the diet because of their low cost and high bioavailability. This study aimed to design and produce the optimum formulation for the gluten-free cake using eggshell powder as rice flour and baking powder replacer by Face-Centered Composite Design. According to the results, it was determined that the optimized formulation should contain 9.85% eggshell powder as a rice flour replacer and 32.78% eggshell powder as a baking powder replacer to obtain a gluten-free cake with a desirable profile in terms of hardness, specific volume, color ($${\text{L}}_{{{\text{crust}}}}^{*}$$ L crust ∗ and $${\text{L}}_{{{\text{crumb}}}}^{*}$$ L crumb ∗ values), ash content, calcium content, and overall acceptability. The gluten-free cake with eggshell powder obtained was characterized as a product rich in calcium, high in ash content, high in specific volume, with a brighter colour and good sensory acceptability. Also, the proximate properties of the gluten-free cake produced with the optimum formulation were also reported. These findings show for the first time that eggshell powder can be used as a rice flour and a baking powder replacer for the formulation of gluten-free cake.

Effect of Minimum Quantity of Lubricant on Carbide Tools and Surface Integrity in the Machining of Titanium Aluminides

Titanium aluminides are being explored as potential materials for the aeronautical sector. However, their application is limited by the high costs of processing and their difficulties in machining. This research evaluates the effectiveness of the minimum quantity lubrication technique (MQL) on the turning process of Ti48Al2Cr2Nb aluminide in terms of tool wear, tool life, cutting forces, surface integrity, and temperature. It was found that MQL conditions can improve the process efficiency, reducing the thermally induced wear mechanisms and enlarging the tool life compared to dry machining. Furthermore, it allows the cutting speed to be incremented, leading to lower processing times. However, MQL seems to not be effective in the reduction of the strain-hardening effect near the machined surface and, although the number of microcracks is reduced, defect-free surfaces cannot be obtained. Moreover, similar microstructural alterations as for dry cutting were detected. The best cutting conditions in terms of surface quality were assessed using the central composite face (CCF) design and surface response methodology. Optimization of the surface roughness under industrially viable cutting conditions was achieved with an average surface roughness value, Ra, of 0.29 µm (feed rate of 0.05 mm/rev, a cutting speed of 54.6 m/min and a depth of cut of 0.125 mm).

Face-Centered Central Composite Design for the Optimization of the Extraction of Phenolic Compounds from Kernels and Shells of Raphia farinifera and Evaluation of the Antioxidant, Antimicrobial, and Anti-Inflammatory Activities

This study reports the extraction of phenolic compound from shells and kernels of the Raphia farinifera fruit and the biological activities of the extract. A face-centered composite design was established to optimize the extraction conditions: ethanol/water ratio (0-100%), solvent/powder ratio (10-30 mL/g), and extraction time (90-180 min). Subsequently, the extracts obtained under the optimal conditions were used for the evaluation of the radical scavenging capacity, the capacity to chelate ferric ions, and the antimicrobial and anti-inflammatory activities. The optimal extraction conditions for the shells are an extraction time of 134.24 min, 65% ethanol in water, and a solvent/substrate ratio of 21.16 mL/g, and for the kernel, an extraction time of 180 min, 94.3% ethanol in water, and a solvent/substrate ratio of 18.6 mL/g. In these conditions, the phenolic compounds were 95.36 mg EAG/L for the shell extract and 139.72 mg EAG/L for the kernel extract. The antioxidant activity revealed that the half-maximal inhibitory concentrations (IC50) of the kernel extracts are 22.32 μg/mL and 55.73 μg/mL for the shells. A reducing activity of Fe 3+ ions with an activity of 308.39 μg EAA/mg for the kernel extracts and 293 μg EAA/mg for the shells was observed. B. cereus was the most sensitive microorganism with a minimum inhibitory concentration (MIC) equal to the minimum bactericidal concentration (MBC) with a value of 156.25 ppm for the kernel extract while the shell extract showed MIC of 625 ppm and MBC of 2500 ppm. The IC50 values for the denaturation of proteins by extracts of shells and kernels are 0.76 μg/mL and 0.56 μg/mL, respectively. Membrane stabilization revealed IC50 values of 1054.54 μg/mL and 1339 μg/mL for the shell and kernel extracts, respectively. This work has shown the potential of Raphia farinifera extracts for the food industry and cosmetics.

Optimization of preparation conditions by response surface methodology for synthesis of titanium dioxide/reduced graphene oxide composite in dye-sensitized solar cells

This study aimed to address the need for alternative materials in the anode layer to enhance the performance of dye-sensitized solar cells (DSSCs). The synthesis of titanium dioxide/reduced graphene oxide (TiO2/rGO) was carried out using the response surface methodology by face central composite design (RSM/FCC). This method allowed us to systematically evaluate the influence of two key factors, namely the weight percentage of precursor graphene oxide (GO wt%) and the L-ascorbic acid ratio, | on the power conversion efficiency (PCE) of DSSCs. Our research is significant because it explores the synthesis of TiO2/rGO as a novel material for the anode layer in DSSCs. This material holds promise for improving device performance due to its unique properties, such as enhanced charge transport and light harvesting capabilities. Additionally, TiO2/rGO can serve multiple functions within the DSSCs device, acting not only as a charge transport layer but also potentially as a light scattering layer to increase photon absorption. The statistical analysis revealed that the GO wt% had a more significant influence on PCE compared to the L-ascorbic acid ratio. Furthermore, our simulation results demonstrated high validity and accuracy, with a correlation coefficient (R2) of 0.9988 and a residual standard error of less than 5 %. The optimized DSSCs-based TiO2/rGO anode achieved a remarkable PCE of 7.12 %, representing a 29 % improvement compared to the pure TiO2-based DSSCs anode. In summary, our study highlights the importance of synthesizing TiO2/rGO as a novel material for the anode layer in DSSCs and demonstrates its potential for significantly enhancing device performance. This study emphasizes these key points more prominently in the abstract to better convey the novelty and significance of our findings.

Ultrasound-assisted extraction of anthocyanin from black rice bran and its encapsulation by complex coacervation

The present work was planned to optimize extraction process of phenolics, flavonoids, monomeric anthocyanin and antioxidants from black rice bran using Ultrasound-assisted extraction and finally utilize it for encapsulation using double emulsion coacervation process. Response surface methodology (RSM) was employed for optimization of extraction process. Acidified ethanol (1 M HCl) was used as extraction solvent and ultrasound power (W) and extraction time (min) were used as independent variables. Face centered composite design (FCCD) data was successfully opted and developed a 2nd order polynomial equation with R2 value of 0.94 for total phenolic content (TPC), 0.95 for total flavonoid content (TFC), 0.87 for 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 0.98 for total anthocyanin content (ANCs) respectively. Kinetic model study for extraction of anthocyanin was compared to conventional extraction process. Characterization of the extracts was performed using high pressure liquid chromatography analysis (HPLC). Cyanidin-3-glucoside is the predominated anthocyanin found as compared to peonidin-3-D-glucoside. Finally, coacervated microcapsules were developed using anthocyanin extract as core solution and gelatin and acacia gum as wall materials. Characterization of the microcapsules in terms of moisture content, hygroscopicity, solubility, encapsulation efficiency and surface morphology were evaluated. The result thus obtained shows that potential anthocyanin content from black rice bran can be utilized as food ingredients for various food application and formulation of functional food.

Visible Light Induced Photocatalytic Removal of Methylene Blue Using Cu-tunable p-type ZnO Nanoparticles.

Removal of phototoxicity and zootoxicity pollutants from the aqueous environment is of great importance to human and aquatic life. Copper-tunable p-type zinc oxide (Cu-ZnO) photocatalysts have been prepared by the chemical co-precipitation method. The structural, morphological, elemental and optical properties of the obtained catalysts were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) analysis and ultraviolet-visible (UV-Vis) spectrophotometry. The diffraction patterns of the as-synthesized catalysts were matched with that of the hexagonal wurtzite structure for the standard ZnO nanoparticles. The photocatalytic activity of the prepared Cu-doped ZnO catalyst was evaluated using methylene blue (MB) dye under various conditions. The effect of operational parameters such as MB initial concentration, catalyst dosage, and solution pH was optimized using a face central composite design (FCCD) of the response surface methodology (RSM). The optimum photodegradation efficiency of 98.00% was found at 0.30g/L catalyst dose, 10.00mg/L initial concentration of MB and initial pH at 6.00. The degradation model was statistically remarkable with p < 0.0001% in which the MB initial concentration and solution pH were the most significant variables influencing the removal of MB over the Cu tunable p-type ZnO photocatalyst under visible light irradiation. Finally, the photocatalytic degradation of MB using the undoped and Cu-doped ZnO nanoparticles was nicely fitted pseudo-first-order kinetics scheme.

Optimization and Kinetics Extraction of Natural Dyes from Henna Leaves (Lawsonia inermis L.) with Ultrasonic Assistance

The Lawson dye contained in the leaves of Lawsonia inermis L. has a red-orange color, which can be used as a fabric dye. The solvent is ethanol because it can attract flavonoid compounds bound to Lawson. The ultrasonic-assisted extraction method is employed to enhance the extraction process by breaking down cell walls, thereby facilitating a more rapid extraction of the desired solute. This study investigated the effects of material-to-solvent ratio, ethanol concentration, and extraction time. The research results were analyzed using a UV-Visible spectrophotometer to determine the yield of Lawson extract. The Face-Centered Composite Design (FCCCD) method was applied to this study to obtain optimal analysis results and extraction conditions. The independent variables in this study were the ratio of ingredients to solvent (0.02-0.06 g/g), ethanol concentration (20-60%), and extraction time (5-15 minutes). The optimal extraction conditions were obtained at a ratio of 0.02 g/g, an ethanol concentration of 60%, and an extraction time of 15 minutes, with a predicted model yield of 15.417%. The actual yield under these conditions was found to be 15.4934%. Furthermore, the extraction kinetics model was analyzed to study and predict the optimal Lawson extraction results. Extraction kinetics calculations were carried out using first-order and second-order based on the Lagergren equation. The most suitable extraction kinetic model is second-order with a determinant coefficient value, or the value of R2 is 1, which indicates that the order kinetic model equation represents the actual conditions.

Biogenic synthesis of ZnO from Rubia cordifolia root extract: A study on sono-photocatalytic dye degradation and anti-bacterial assay

ZnO is a semiconductor metal oxide with unique antibacterial and photocatalytic properties. Green synthesis of nanoparticle is environmentally friendly procedure, imparting multiple properties to the nanoparticles (NPs). This study reports Rubia cordifolia root extract mediated ZnO NP synthesis. Synthesised NPs were analysed for antibacterial properties and sonication assisted photocatalytic dye degradation experiments were performed. Synthesised ZnO NPs were characterized employing UV-VIS spectroscopy, X-Ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) followed by energy dispersive X-ray spectroscopy (EDX) analysis and was compared with commercial grade ZnO. UV-VIS adsorption peak of NPs was found at 375 nm with a bandgap of 3.2 eV. The NPs reveals to have a crystalline size of 17.54 nm with a hexagonal wurtzite structure and clustered flakes with rose petal morphology were identified through XRD and SEM analysis respectively. The green ZnO possesses good antibacterial properties against both gram positive (Staphyllococcus aureus) and gram negative bacteria (E.coli). Study on the effectiveness of synthesised ZnO for ultrasound sonication-assisted photocatalysis over normal photocatalytic degradation were carried out through response surface methodology with face central composite design. The regression models (R2adj > 90 % and R2pred > 90 %) were confirmed by analysis of variance (ANOVA), and optimization was performed. The green ZnO nanoparticle was capable of degrading alizarine red up to 92.89 % and rhodamine B up to 89.95 % under optimal conditions and were also compared with commercial ZnO NPs. Reusability of the photocatalyst was confirmed by conducting 4 cycles of experiments at optimum condition.

Fast simultaneous electrochemical detection of Bisphenol-A and Bisphenol-S in urban wastewater using a graphene oxide-iron nanoparticles hybrid sensor

In this work, a novel and sensitive electrochemical sensor was developed for the simultaneous determination of low concentration levels of Bisphenol-A (BPA) and Bisphenol-S (BPS) in a secondary effluent from a wastewater treatment plant and surface water. The sensor design involved the utilization of a glassy carbon electrode that was modified with hybrid iron nanoparticles and a nanostructure of graphene oxide. The synthesized material displayed a stable heterostructure, facilitating efficient electronic transfer and exhibiting impressive electrocatalytic capacity. Furthermore, the sensor successfully detected anodic signals of BPA and BPS with a peak separation of 0.28 V, confirming its excellent performance. For method optimization, a chemometric tool based on a Central Composite Face (CCF) design response surface was employed. The optimized conditions yielded an analytical curve with a linear range of 15.0 to 120.0 µmol L−1 for BPA, represented by the equation Iap (µA)= -0.088 + 0.044 (µA L µmol−1) [cBPA], and 20.0 to 70.0 µmol L−1 for BPS, represented by the equation Iap (µA)= -0.367 + 0.025 (µA L µmol−1) [cBPS]. The detection and quantification limits for BPA were established at 12.05 and 36.51 µmol L−1, respectively. Similarly, for BPS, the corresponding values were determined to be 11.63 and 35.24 µmol L−1. The electrochemical method developed was validated by comparing it with the high-performance liquid chromatography coupled to diode array detector (HPLC-DAD) technique. Notably, the electrochemical method demonstrated to be successful in the simultaneous detection and quantification of BPA and BPS in a secondary effluent and surface water.

Solar heterogeneous photo-Fenton for complete inactivation of Escherichia coli and Salmonella typhimurium in secondary-treated wastewater effluent

In this work, complete elimination of Escherichia coli and Salmonella typhimurium was achieved in 120 min using a heterogeneous photo-Fenton process under sunlight at pH 6.5 in distilled water. A face-centered composite central design 22 with one categoric factor and three replicates at the central point was used to evaluate the effect of iron (III) oxide concentration (0.8–3.4 mg L−1), H2O2 (2–10 mg L−1), and the type of iron oxide phase (maghemite and hematite) on the inactivation of both bacteria. The results showed that the amount of catalyst, H2O2 concentration and their interaction were significant factors (p < 0.05) in the elimination of the microorganisms. Thus, under the best conditions (3.4 mg L−1 of iron (III) oxide and 10 mg L−1 of H2O2) in the experimental ranges, complete inactivation of E. coli and S. typhimurium was achieved (6-log reduction) in 120 min using the photo-Fenton treatment with both iron-oxide phases. Furthermore, the photocatalytic elimination of both bacteria by the photo-Fenton process using hematite and maghemite in secondary-treated wastewater effluent was performed obtaining slower inactivation rates (1.2–5.9 times) than in distilled water due to the matrix effect of the effluent from a wastewater treatment plant. Nevertheless, the process continued to be effective in the effluent, achieving complete bacterial elimination in 150 min using the hematite phase. Additionally, the SEM images of the bacterial cells showed that the heterogeneous photo-Fenton treatment generated permanent and irreversible cell damage, resulting in complete cell death.

Migration study of phthalates from non-food plastic containers used in food preservation

Phthalate acid esters (PAE) are used as additives in the formulation of plastics, to increase their flexibility and transparency. They can migrate from plastic packaging to food, then cause endocrine disruption in consumers. This migration depends on the conditions of use defined for each plastic. Non-food plastics are likely to release more PAE than food-grade plastics. In Cameroon, non-food grade plastics such as old paint buckets are used by people to preserve liquid food. The present work aimed at studying the conditions and mechanism of migration of total PAE from paint buckets to pap. For this purpose, the effects of seven factors were determined through Plackett-Burman experimental design. The interactions of the most influential factors were determined through a full factorial design. The conditions of the migration of total PAE were obtained via face-centered composite design. Then experimental results of migration kinetics were modelled according to equations of pseudo-first order, pseudo-second order and intra-particle diffusion. The results revealed that the most influential factors were pH, temperature and contact time. The effects of these factors are non-linear, and their interactions have to be considered. When pap is preserved in paint buckets according to the conditions: temperature of pap >70 °C, pH of pap ≤4 or ≥10 and contact time > 2 h, as is the case in donut shops in Cameroon, the amount of total PAE released is greater than 50 μg/L. Migration of total PAE from paint buckets to pap is best described by the pseudo-second order model.

Utilization of triethylammonium hydrogen sulphate-mediated solvent for optimization of asiaticoside extraction and antioxidant capacity of Centella asiatica (L.)

Asiaticoside, a pentacyclic triterpene of Centella asiatica with broad pharmacological actions. Higher asiaticoside content of Centella extracts in food products increases their nutritional and medicinal values. Protic ionic liquids (PIL) were utilized as bioactive extraction additives. The research focuses on obtaining the optimum extraction parameters for higher asiaticoside yield, and Centella extract antioxidant capacity. Optimization of all responses (asiaticoside yield, TPC, TEAC) achieved through faced-centered composite design (FCCD) involving three factors (temperature, extraction time, and triethylammonium hydrogen sulfate, [TEA][HSO4] %). The optimal conditions were 66 °C, 12 h duration, and 20% [TEA][HSO4], which resulted in 4.44 ± 0.05% (w/w) asiaticoside, TPC of 114.11 ± 12.58 mg GAE /g and TEAC of 70.01 ± 5.74 µmol TE/g respectively. All responses fit the quadratic model with proximity between predicted and experimented values. Procurement of higher asiaticoside yield, TPC, and TEAC verified the pertinent of the optimal conditions. In addition, the outcomes give an overview of PILs potential for higher bioactive extractions. Research expansion by utilizing other PILs for plant extraction in addition to solute–solvent interaction study will be beneficial for the designation of an efficient plant extraction process that maximizes the plant-based product market.

Biochemical Characterization of Microbial Isolates and Effect of Concentration and Incubation Time of Plant and Cow Milk Yoghurt using Response Surface Methodology

The objective of the research was to evaluate the biochemical characteristics of the various microbial isolates used in the production of plant based yoghurt, the optimal growth temperatures and the effect of incubation time and inoculum concentration on the taste and desirability of the yoghurt. Pure cultures of five (5) microbial strains (Lactobacillus acidophilus; Lactobacillus bulgaricus; Lactobacillus casei; Lactobacillus lactis; Streptococcus thermophilus) were obtained from commercial yoghurt and evaluated for their biochemical characteristics, bacterial growth temperatures and synersis. The isolated organisms were used to ferment plant-based milk product produced from blends of tigernut, Dates and Coconut. Response Surface Methodology (Face centered composite design) was used to obtain an optimized ratio formulation of 0.167 for coconut, 0.667 fortigernut and 0.167 for dates. Bacterial growth temperatures were evaluated at 4°C, 27°C, 37°C,40°C, 45°C and 60°C respectively. Results showed that full bacterial growth was noticed at temperatures of 40-45°C. The taste of the yoghurt improved from 6.58 to 6.71 when the incubation temperature changed from about 45°C to 44°C and the duration of incubation changed from 15.4 hrs to 14.7 hrs.

Response surface methodology mediated optimization of diclofenac and norfloxacin biodegradation using laccase immobilized on metal–organic frameworks

In this work, laccase immobilized on a zeolitic imidazolate framework (Lac-ZIF) is used as a biocatalytic composite to decontaminate pharmaceutically active compounds (PhACs): diclofenac (DFC), and norfloxacin (NOR). A central composite face (CCF) design was used, and operational parameters were optimized using a quadratic response surface methodology (RSM) regression model, resulting in pH 6.4, 10 mg Lac-ZIF dosage, 10.4 mg L−1 initial concentration, and 8 h contact time. The model proved viable and effective for application in this study, giving predictions of 93.9 and 95.1% removal efficiencies of DFC and NOR, which were confirmed by actual experimental results with high accuracy. The Lac-ZIF revealed enhanced thermal stability with subsequently higher deactivation energies (Ed) than the free form of laccase. Additionally, the application of the biocatalyst in the treatment of real water samples, outperformed the free laccase by approximately 1.5 folds. Furthermore, the Lac-ZIF preserved 79 and 83% residual removal efficiencies after 6 cycles of reuse, with enhanced storage stabilities of 87.2 and 91.1% efficacies at 25 days for storage for DFC and NOR elimination, respectively. This study, therefore, demonstrates the potential of laccase immobilized on ZIFs for efficient biodegradation of DFC and NOR, which can be exploited for the remediation of wastewater containing PhACs.

Plackett–Burman and face-centered composite designs for development and optimization of chromatographic method for the simultaneous determination of glycopyrronium, indacaterol and mometasone in their fixed dose combination inhaler – Green profile assessment

A novel simple, specific, sensitive, accurate and precise reversed phase high performance liquid chromatographic method (RP-HPLC/UV) was developed and validated for the simultaneous estimation of Glycopyrronium bromide (GLY), Indacaterol acetate (IND) and Mometasone furoate (MOF) in pure form, in laboratory prepared mixtures and in pharmaceutical dosage form. Experimental design methodology was applied by using Plackett–Burman and face-centered composite designs to achieve the best resolution with minimum experimental trials. The designed model was statistically analyzed, graphically presented by surface plots and the relationships between coefficients of the derived polynomial equations were interpreted. Chromatographic separation was achieved on Inertsil ODS C18 column (250 ×4.6 mm, 5 µm) at ambient temperature using a mobile phase composed of methanol: 0.1% glacial acetic acid (pH4) in a gradient elution at a flow rate 1 mL /min. UV detection was carried out at 233 nm. Response was found to be linear in the concentration range of 20–120 µg /mL with regression coefficient (r2 = 0.999) for GLY, 50–300 µg /mL with regression coefficient (r2 = 0.9995) for IND and 50–300 µg /mL with regression coefficient (r2 = 0.9998) for MOF. The method was validated as per ICH guidelines and satisfactory results were achieved. The method was successfully applied for the analysis of the cited drugs in their fixed dose combination (FDC) pharmaceutical formulation. Statistical comparison between the results obtained by the proposed method and the reference methods for GLY, IND and MOF showed no significant difference. The developed method could be implemented in quality control aspects of the cited drugs. Four green metrics were used to evaluate the new RP-HPLC/UV method's greenness and compare it to other published techniques.