Optimal Mobile Research Articles

Theoretical Study on Optoelectronic Properties of 1,4-Dithiazole-5,10-dihydrophenazine and Its B ← N-Fused Derivatives.

Recently, Liu et al. reported 1,4-dithiazole-5,10-dihydrophenazine (DTDHP) and its B ← N-fused derivative (DTHDHP-BF2), which were expected to show excellent optoelectronic properties (Angew. Chem. Int. Ed. 2022, 61, e202205893). However, their charge-transport performance and luminescence emission mechanisms have not been revealed. In this work, we used density functional theory (DFT) calculations to investigate the optoelectronic properties of DTDHP and DTHDHP-BF2 and analyzed the influence of the introduction of -BF2 on the basic parameters governing charge transport and injection in detail. Our calculation results showed that adding -BF2 could stabilize the frontier molecular orbitals and decrease the reorganization energies associated with electron transport due to the formation of B ← N bonds, and the intermolecular electronic couplings are greatly enhanced owing to the strong intermolecular F···H interactions. Based on the master equation coupled with the Marcus-Hush electron transfer theory, we theoretically predicted the charge transport properties of DTDHP and DTHDHP-BF2. The optimum hole mobility (3.87 cm2 V-1 S-1) and electron mobility (1.52 cm2 V-1 S-1) of DTHDHP-BF2 are, respectively, 3 and 9 times as high as the corresponding optimum values of compound DTDHP. Moreover, the assignments of multiple fluorescence bands in the experiment were confirmed by time-dependent density functional theory (TDDFT) calculations. The simulated emission spectra indicate that the experimental fluorescence maxima at 687 nm originates from the S1 → S0 transition of the double proton transfer phototautomer (T2H) of DTDHP, and the shoulder peak at ∼660 nm may be related to the excited-state single-proton transfer phototautomer (T1H); for DTHDHP-BF2, the experimental fluorescence maxima at 687 nm should be attributed to normal Stokes shifted emission, and the shifted fluorescence with a peak at 751 nm originates from the emission of the photodissociation product of DTHDHP-BF2.

A mechanistic approach to determine the relationship between film structure, electronic properties, and photocatalytic activity of ALD ZnO thin films on glass gibers

Atomic layer deposition (ALD), a high-conformality thin-film deposition technique, offers the opportunity to immobilize photocatalytic materials on high surface area substrates. Textile substrates are inexpensive, easily accessible materials with a fibrous nature, making them high surface area scaffolds for photocatalytic applications. This study applied ZnO thin-film coatings to fabric structures with different numbers of ALD cycles. The effect of coating thickness on the surface and electronic properties of the films and their photocatalytic properties were investigated. SEM, XRD, PL, and UV–Vis were used to examine the surface morphology, crystal structure, defects, and optical properties of the ZnO thin films. As the film thickness increased, the crystal sizes and the number of defects in the structure increased. Contact angle and Hall Effect measurements revealed that these structural defects are present on the surface of the films. Optimum wettability, mobility, and photocatalytic efficiency values were observed in the 15-nm coated samples, resulting in the highest photocatalytic activity and a turning point.

Utilizing experimental design and desirability function in optimizing RP-HPLC method for simultaneous determination of some skeletal muscle relaxants and analgesics

An experimental design and response surface methodologies using Plackett–Burman and Box-Behnken designs were applied for selecting and optimizing the most appropriate parameters which significantly affect the separation and quantitative estimation of five skeletal muscle relaxants and four analgesic drugs (baclofen, methocarbamol, dantrolene sodium, orphenadrine citrate, cyclobenzaprine hydrochloride, ketoprofen, etoricoxib, ibuprofen, and mefenamic acid) with a relatively short duration of analysis in a single run. For the separation of the nine drugs, an INERTSIL ODS-V3-5 µm C18 column (250 × 4.6 mm I.D.) was used with the optimum mobile phase conditions (45.15 mM ammonium acetate buffer pH 5.56 adjusted with acetic acid, acetonitrile, and methanol in a ratio of 30.5:29.5:40, v/v/v with a flow rate of 1.5 mL/min) and UV-detection at 220 nm. The optimized method was successfully subjected to the validation steps as described in ICH guidelines for linearity, precision, accuracy, robustness, and sensitivity. The optimized and validated method was effectively applied to determine the content of the studied drugs in their pharmaceutical preparations and to expand its applicability to the counterfeit estimation of etoricoxib in different brands of tablet dosage forms.

Influence of highly optimized charge carrier mobility and diverse physical features toward efficient organic solar cells

Organic solar cells (OSCs) exhibit potential in low-emissive photovoltaic (PV) technology by enhancing excitonic absorption, higher trap-assist recombination, lower excitons diffusion length (Ln,p), and carrier lifetime (τ n,p). The main challenge remains the asymmetric carrier mobility (μ n,p) of the organic absorbing layer (OAL) and various physical factors affecting efficiency (η). This effort has been explored through the attributes of different fullerene derivatives based on binary blends of OAL thickness that suggest new physical insights into the roles of several contributions in the PV performances under intense light illumination. The relationship between optimum mobility ratio (β) and lower trap-state density (Nt) of OAL in OSC structures for inclusive η has been collectively investigated. With a very thin OAL and pioneering transparent hole transport layers (HTLs) can significantly reduce recombination loss and enhance transparency, focusing on near-infrared band absorption and thin hetero-interface design for η and stability. The improved thin OALs, tunable absorption bands, and carrier selectivity address efficiency–transparency trade-offs and reproducibility concerns. The outcome revealed a stable η of 6.27% with a 250 nm thinnest OAL at a temperature of 300 K, which may be interpreted as a coupled framework for effective optimization strategies to accomplish balance between photogeneration and charge carrier recombination. Thus, the observed hypothetically analyzed results have verified the further optimization of OAL thickness for fabrication perspectives with a typical interpretation of ohmic contact.

The effects of interfacial layers on dielectric properties of an acrylic co-polymer containing polymer-grafted reduced graphene oxide

In this study, the influence of interfacial layers, in addition to other effective parameters, on the dielectric efficiency of polymer nanocomposites in the rubbery state is presented. For this purpose, reduced graphene oxide (rGO) was grafted by poly (butyl acrylate) chains (rGO-PBA) via surface-initiated atom transfer radical polymerization (SI-ATRP) and incorporated into an acrylic co-polymer matrix with the glass-transition temperature (Tg) well below room temperature. The rGO exhibited poor dispersion and uneven distribution in acrylic co-polymer, whereas polymer grafted-rGO showed excellent dispersion. The grafted chains can penetrate and form entropic interactions with the matrix chains, which results in a strong interfacial region. The immobilized interfacial layer was characterized by DSC and dielectric measurements. The dielectric measurements in different temperatures provided the means to evaluate the contribution of the interfacial layers on dielectric properties. The findings confirmed that there exists an optimum chain mobility in which the chain polarization shows a major contribution to the dielectric properties of polymer nanocomposites. Reduction of temperature to a certain degree exhibited more rise in the dielectric properties of polymer/rGO-PBA nanocomposites than pure matrix which can be correlated to the interfacial region.

Thin Layer Chromatography Fingerprint Analysis of Tempuyung (Sonchus arvensis L.)

Thin layer chromatography (TLC) fingerprint profile analysis can be used for quality control of herbal medicinal raw materials through identification, authentication, and discrimination. This study aims to develop a fingerprint analysis method for tempuyung TLC (Sonchus arvensis L.), which is then used for quality control. Tempuyung was extracted with methanol using ultrasonication which was then analyzed using the developed fingerprint TLC method. The optimum mobile phase used to separate compounds from tempuyung was a composition of chloroform: ethyl acetate: dichloromethane: formic acid (7.5:2:0.5:0.1) and produced eleven bands. The mobile phase composition produced good separation and had a typical luteolin band with an Rf value of 0.22, detected under UV 366 nm and derivatized with 10% sulfuric acid reagent. This method was applied to tempuyung from three locations, including Malang, Solo, and Yogyakarta, whose fingerprint patterns did not differ significantly. The fingerprint method has been validated and met the acceptance requirements for quality control of tempuyung.

Extraction and quantification of melatonin in cornelian cherry (Cornus mas L.) by ultra-fast liquid chromatography coupled to fluorescence detector (UFLC-FD)

AbstractWild edible plants (WEPs) can be widely found in the world and defined as native species that grow naturally in their natural habitat. They have become part of the traditional food as human diet and used in folk medicine to treat diseases. They are very rich in terms of nutraceuticals. Melatonin is a natural hormone providing several benefits for human health. It has functions such as regulating growth and development and increasing tolerance to environmental stress factors in plants. It is stated that the serum melatonin level in humans increases after intake of foods containing melatonin. This study examined the presence of melatonin in wild grown cornelian cherry fruits by UFLC-FD and determined suitable extraction and chromatographic conditions. The optimum mobile phase, excitation/emission wavelength, and extraction solvent were determined as methanol: water: acetic acid, 275/345 nm, and methanol: water: HCl, respectively. Melatonin content in fruits ranged from 130.82 to 201.84 ng g−1 in fresh fruit.

The role of a highly optimized approach with superior transparent conductive oxide anode towards efficient organic solar cell

The effort emphasizes the numerical analysis of different transparent conducting oxides (TCOs) perspectives, which include ITO, FTO, AZO, and IZO anode-based organic solar cells (OSCs) with the drift-diffusion approach. The prior selection of aluminum-doped zinc oxide (AZO) as TCO is feasible for more extended transparency and antireflection due to a tailored absorption wavelength of <380 nm and the factors of higher mechanical flexibility, low-cost processing, and realistic performance at lower temperatures. To confirm the stability and reproducibility of the design OSC, the contribution of each interfacial layer thickness, i.e., AZO as TCOs, P3HT: PC61BM as an organic absorbing layer (OAL), Spiro-OMeTAD (SOT) as a hole-transport layer (HTL), and ZnO as an electron-transport layer (ETL), is also investigated. Furthermore, functions of optimum trap-state densities () and charge carrier mobility () in OAL have been performed to aid in increasing the diffusion length of excitons carriers (). These properties led to better photogeneration and transport of charge carriers, decreasing the series resistance (RS), leading to lower bimolecular recombination, a long carrier lifetime (), and consequently higher power conversion efficiency (PCE). The findings revealed that the proposed OSC structure achieves an excellent PCE of 10.28% for AZO as TCO with an 850 nm ultra-thick OAL under AM 1.5 G light irradiation. Hence, a better fabrication process for efficient OSC could also be improved by the optimization of all these critical factors for future research.

Safe Displacements Device for All Conditions Blind People

One of the challenges faced by the blind to achieve optimum mobility is obstacles detection and avoidance. The traditional aid is the mobility white cane, but nowadays, there are also electronic travel aids. However, none of them is widely used. The eBAT (electronic Buzzer for Autonomous Travel) has been designed to provide protection and easy usage, interacting with a user’s mobile phone. To improve its performance, a usage test was carried out by 25 totally blind users divided by sex, age range and autonomy in mobility. The main results are that the eBAT gives a reduction in the involuntary contacts but also decreases the walking speed. There are differences between sex, age and mobility groups but with limited statistical significance, and there are also some correlations between variables.

Stability indicating HPLC method development and validation of Fostemsavir in bulk and marketed formulations by implementing QbD approach

Background: Achieving a predictable degree of quality with intended and planned specifications is known as "quality by design." QbD (Quality-by-Design) is an alternative to conventional method development that places more attention on identifying and mitigating potential risks. Component of the Quality-by-Design methodology involves conducting a series of experiments to learn how various factors, including the dependant variables, affect the answers of interest. Here, we use a QbD (Quality-by-Design) loom to detail the creation and verification of a stability-indicating high-performance liquid chromatography (HPLC) method for Fostemsavir in both bulk and finished-goods forms.&#x0D; Results:&#x0D; In this work, we present a workable experimental design for optimising the RP-HPLC separation technique by identifying the optimum mobile phase concentration and flow rate. Below are the ideal chromatographic conditions as calculated by Design Expert version 13.0: Mobile phase: 80 parts acetonitrile to 20 parts formic acid (v/v), flow rate: 0.8 millilitres per minute, retention time: 3.24 minutes, column dimensions: GIST C18 (250 mm × 4.6 mm × 5.0 μm).&#x0D; Here we propose a practical experimental layout for determining the optimal mobile phase concentration and flow rate for the RP-HPLC separation technique. Using Design Expert version 13.0, the optimum chromatographic conditions were determined to be as follows: Shim-pack GIST C18 (250 mm 4.6 mm, 5.0 μ), mobile phase acetonitrile to 1% formic acid (80:20, v/v), flow rate 0.8 ml/min, and retention period 3.24 min.&#x0D; At a detection wavelength of 266 nm, it was discovered that the devised technique was linear over a concentration range of 50-90 μg/ml (r2 = 0.997). Test parameters for the system's appropriateness were determined to be 1.124 for the tailing factor and 9480 for the theoretical plates. Intraday RSD was found to range from 0.70 to 0.94, whereas interday RSD was found to range from 0.55 to 0.95 percent. Values for robustness were under 2%. The solution stability % RSD was calculated to be 0.83. The result of the assay was 100.05 percent. The created methodologies were used to studies of forced degradation, and the stressed materials were analysed. The parameters used to validate the procedure fell within the acceptable range recommended by ICH.&#x0D; Conclusion: Using Design Expert 13.0, we created a central composite design experiment that illustrates the relationships between mobile phase and flow rate across three levels, with retention duration, tailing factor, as well as theoretical plates as the responses of interest. By this work, we gain insight into the variables that affect chromatographic separation and strengthen our conviction that the HPLC method we've devised will serve our needs. Quantitative method development was applied to improve comprehension of multi-tiered method variables.

Development and Validation of a RP-HPLC Method for the determination of Venlafaxine hydrochloride in bulk and Pharmaceutical Dosage Forms

A simple, accurate, precise and rapid reverse phase high performance liquid chromatography method was developed and validated for the analysis of venlafaxine hydrochloride in bulk and marketed pharmaceutical dosage form. The chromatographic separation was carried out using a Phenomenex C18, (250mm × 4.6mm × 5µ) column. The optimum mobile phase consisted of ammonium acetate buffer, methanol (60:40) with pH adjusted to 5. The mobile phase was delivered isocratically at a flow rate of 1mL/min with UV detection at 227nm. Venlafaxine hydrochloride was eluted at 2 minutes. The method was validated for linearity, precision, accuracy, robustness and recovery. The method was linear in the concentration range of 15-165µg/ml with correlation coefficient 0.9997. limit of detection and limit and quantification were found to be 185ng/ml and 563ng/ml respectively.

Direct chiral separation of abscisic acid by high-performance liquid chromatography with a phenyl column and a mobile phase containing γ-cyclodextrin.

Abscisic acid (2-cis,4-trans-abscisic acid) is a plant hormone that has an asymmetric carbon atom. We tried to separate the enantiomers of native abscisic acid by HPLC using a phenyl column and a chiral mobile phase containing γ-cyclodextrin. The optimum mobile phase conditions were found to be 0.8% (w/v) γ-cyclodextrin, 4% (v/v) acetonitrile, and 20mM phosphate buffer (pH 6.0). It was found that (R)-abscisic acid was earlier detected than (S)-abscisic acid. Since γ-cyclodextrin is hardly retained on a phenyl column, it was suggested that (R)-abscisic acid formed a more stable complex with γ-cyclodextrin than the (S)-abscisic acid. Abscisic acid in an acacia honey sample was successfully enantioseparated with the proposed method and only (S)-abscisic acid was detected. A biologically inactive 2-trans,4-trans-abscisic acid, which was prepared by irradiation of abscisic acid with a light-emitting diode lamp at 365nm, was partially enantioseparated by the proposed method. Since the irradiation of (S)-abscisic acid-induced cis-to-trans isomerization to produce one 2-trans,4-trans-abscisic acid enantiomer, it is reasonable that racemization did not proceed during the cis-to-trans isomerization. (S)-Abscisic acid and probably (S)-2-trans,4-trans-abscisic acid were detected in a honey sample, where the peak area of (S)-abscisic acid was 7 times larger than that of (S)-2-trans,4-trans-abscisic acid.

Simultaneous Determination of Vitamin E and γ-Oryzanol in Rice Bran Oil via HPSEC-PDA without Sample Pretreatment.

Vitamin E (tocopherols and tocotrienols) and γ-oryzanol are two minor constituents of rice bran oil (RBO) and are known to be potential bioactive compounds. The content of γ-oryzanol, a unique antioxidant found only in RBO, is a key factor in determining the retail price of the oil. Limitations of conventional HPLC columns for vitamin E and γ-oryzanol analysis are the alteration of these components and the time-consuming need for pretreatment of samples by saponification. High-performance size exclusion chromatography (HPSEC) equipped with a universal evaporative light scattering detector (ELSD) is a versatile tool for screening optimum mobile phase conditions because components of the sample can be separated and detected in the same run. In this work, the RBO components (triacylglycerol, tocopherols, tocotrienols, and γ-oryzanol) assessed on a single 100-Å Phenogel column using ethyl acetate/isooctane/acetic acid (30:70:0.1, v/v/v) as the mobile phase provided baseline separations (R s >1.5) with a total run time of 20 min. The HPSEC condition was then transferred to determine the content of tocopherols, tocotrienols, and γ-oryzanol in RBO products using a selective PDA detector. The limit of detection (LOD) and limit of quantification (LOQ) of α-tocopherol, α-tocotrienol, and γ-oryzanol were 0.34 and 1.03 μg/mL, 0.26 and 0.79 μg/mL and 2.04 and 6.17 μg/mL, respectively. This method was precise and accurate, with a percentage of relative standard deviation (%RSD) of the retention time of less than 0.21%. The intra-day and inter-day variations were 0.15-5.05% and 0.98-4.29% for vitamin E and γ-oryzanol, respectively. The recoveries of tocopherols, tocotrienols, and γ-oryzanol ranged between 90.75% and 107.98%. Thus, the developed HPSEC-ELSD-PDA method is a powerful analytical tool for determining the vitamin E and γ-oryzanol present in oil samples without requiring any sample pretreatment.

Analytical reversed‐phase high‐performance liquid chromatography method development for silodosin and solifenacin in bulk and marketed formulation using analytical quality by design approach

AbstractA reliable HPLC method for the simultaneous estimation of Silodosin and Solifenacin was developed using the quality by design approach. In this study, the main goal was to find a dependable chromatographic system for acceptable component separation. The peaks were sharp within a reasonable run time. For the risk measurement related to the study, critical quality attributes were evaluated. To create an analytical design and a control strategy, the quantitative relationship between critical materials attributes and critical quality attributes was built utilizing the Box‐Behnken design. The optimum and ideal mobile phase ratio selected as per the quality by design approach was acetonitrile:methanol:buffer (50:20:30, v/v/v) which has a pH 4.5 flow rate of 1 ml/min. The buffer system used in this mobile phase was potassium dihydrogen orthophosphate. The retention time for Silodosin and Solifenacin determined was 3.626 and 5.754 min. respectively at λmax = 210 nm. The R2 value calculated for Silodosin and Solifenacin was 0.9994 and 0.9982, respectively. The related standard deviation was less than 2% for the developed method showing good reproducibility and recovery. A simple, precise, and repeatable high‐performance liquid chromatography method for regular quality control testing was developed simultaneously by applying a quality by design approach.

Synthesis and pore-scale visualization studies of enhanced oil recovery mechanisms of rice straw silica nanoparticles

There is increasing interest in synthesis of silicon dioxide (SiO2) nanoparticles from agricultural biomass waste because the process is cost-efficient and eco-friendly. However, the application of rice straw SiO2 nanoparticles as enhanced oil recovery (EOR) agents have not been examined in detail. Moreover, the pore-scale mechanisms governing the mobilization and displacement of resident oil during rice straw silica nanofluids (RS SNF) flooding is rarely reported in literature. In this study, SiO2 nanoparticles (nanosilica) were synthesized from rice straw and characterized. Oil-water interfacial tension (IFT) and contact angles were measured to assess the performance of RS SNF as EOR agents. Pore-scale visualization experiments were conducted using 2-dimensional micromodel to identify the prevailing EOR mechanisms of RS SNF flooding. Significant reduction in oil-water IFT and contact angles were obtained in presence of RS SNF. These results were comparable to the performance of commercial silica nanofluids, suggesting that RS SNF could be utilized as favourable substitute to commercial SNF. The ideal rice straw nanosilica concentration for achieving optimum residual oil mobilization and microscopic sweep was identified as 0.1 wt% from pore-scale visualization experiments. At similar conditions, the oil retained (oil saturation) within the micromodel was determined by Image J software as 28.51% after 0.05 wt% RS SNF flooding and 23.73% after 0.1 wt% RS SNF flooding. The oil trapped in the micromodel after rice straw nanosilica–SDS and commercial nanosilica–SDS solutions injections were comparable at 19.35% and 18.33% respectively. The displacement efficiency and microscopic sweep was much higher when the synergy of nanoparticles and 0.2 wt% sodium dodecyl sulfate (SDS) solutions were injected into the micromodel due to the lowest oil-water IFT and contact angles achieved by SiO2/SDS solutions. The SiO2/SDS fluid front propagated uniformly and in piston-like movement pattern, suggesting that the impact of viscous force over capillary oil retention forces was significantly higher. During nanofluids flooding, uniform invasion of the displacing fluid was observed at the onset of fluid injection, the nanofluid become thicker whereas the oil become thinner with the advancement of the displacing front. However, fingering of the displacing fluid front was noticed with time, resulting in progression of displacement fronts with dendritic and dispersive patterns.

ARTIFICIAL INTELLIGENCE - BASED MULTIOPATH TRANSMISSION MODEL FOR WSN ENERGY EFFICIENCY

This paper presents a network-coding-based transmission strategy called alternative multipath to boost the transmission reliability and energy efficiency of wireless sensor networks (AMNC). Encoded data packets are transmitted to the sink through alternative multipath from the cluster head. MATLAB 7.0 simulates WSNs energy utilization and reliability. Simulation findings show AMNC outperforms parallel multipath based on network coding. The two techniques show this. A well-defined discussion of the research subject, specific technologies, strengths and weaknesses, scopes, and problem formulation is required for any study. The ocean covers approximately two-thirds of the earths surface, therefore its hard for any economy to avoid it (i.e., country). The ocean serves as a main method of transportation, supports international trade, and is crucial for defense. In recent years, it has come to light how crucial ocean or water-routes are for enabling rapid and cost-effective transportation for the expansion of businesses. In order to realize transcontinental commercial practices and discover the true meaning of socioeconomic globalization, the role that oceanic waterways have played has been essential. On the other hand, maintaining efficient real-time environmental or auditory conditioning (also known as condition awareness) is required in order to make optimum mobility possible. Because of its exceptionally high dynamic network topology, an audio channel experiences a significant amount of network deviation as a result, it calls for a communication paradigm that is more effective in order to support the aforementioned application environment.

Analytical Method Development and Validation for Determination of Doravirine by RP-HPLC

An easy, specific and precise RP-HPLC technique has been created and tested for the quantification of doravirine in pure and its tablet dosage forms. Doravirine is a novel nonnucleoside reverse transcriptase inhibitor (NNRTI). It is utilized in the treatment of HIV-1 infection in combination with other antiviral medications therapies (ARTs). The separation was completed on the Agilent C18 column (150 x 4.6 mm) with 5µ particle size. 0.01N potassium dihydrogen phosphate and acetonitrile (ACN) (60:40 v/v), at a flow rate of 1ml/min, was used as an optimum mobile phase. The wavelength chosen was 210 nm. The retention time for doravirine was 2.379 min. Linearity of doravirine was found to be 25- 150μg/ml. Linearity equation attained was y= 11776x+ 2813 with correlation coefficient 0.999. The relative standard deviation for precision was found to be less than 2%. % Recovery was found as 100.13% for doravirine. The LOD and LOQ for doravirine were found as 0.06 µg/ml and 0.18 µg/ml. Keywords: Doravirine, Method Development, Validation, RP-HPLC

VALIDASI METODE ANALISIS SENYAWA ETIL p-METOKSISINAMAT DALAM PLASMA DARAH TIKUS PUTIH JANTAN GALUR WISTAR MENGGUNAKAN KROMATOGRAFI CAIR KINERJA TINGGI

Ethyl p-methoxycinnamate (EPMC) isolated from the rhizome of kencur (Kaempferia galanga L) is being developed at STFI. Validation of EPMC analysis in blood plasma using High-Performance Liquid Chromatography (HPLC) needs to be conducted to perform in vivo EPMC analysis. This study aims to validate the EPMC analysis method in blood plasma using HPLC. The HPLC column used is column C18, with methanol : phosphoric acid 70:30 and 80:20 mobile phases, a flow rate of 1.0 mL/min, and a maximum wavelength of 310 nm. The blood plasma used was the blood plasma of white male rats of the Wistar strain. EPMC was added to blood plasma and analyzed using HPLC. Parameter validation used is system suitability test, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). The results showed that the optimum mobile phase for analyzing EPMS in plasma was methanol : phosphoric acid with a ratio of 70:30. Based on the validation, the linear regression was 0.998. In the accuracy test, the average value range for the percent recovery is 98% - 102%. In the precision test, the average value of the RSD percentage was 4.10% - 68.83%. The LOD value is 2.747 g/mL, and the LOQ value is 9.158 g/mL. Based on this research, it can be concluded that EPMC in blood plasma can be analyzed using KKKT with column C18 and mobile phase methanol : phosphoric acid 70:30.

Xanthan gum-added natural surfactant solution of Chuback: A green and clean technique for enhanced oil recovery

Enhanced oil recovery (EOR) is one of the most important branches of petroleum engineering. For this purpose, the surfactant flooding method remains one of the primary methods because of the prospects of wettability adjustment and a decrease in oil-water interfacial tension (IFT). However, environmental load and high costs make synthetic organic surfactants flooding inefficient and uneconomical under certain conditions. A new natural surfactant, viz. Chuback, was introduced in this study because natural surfactants are environmentally benign, nonhazardous, and cost-effective. The effects of adding bio-based xanthan gum (XG) and increasing the salinity on the wettability adjustment, IFT, rheological behaviors, and core flooding characteristics were investigated in terms of the performance of the designed surfactant-polymer flooding system. The results showed that Chuback is very efficient in wettability alteration from an oil-wet state to a water-wet state with an increase in the oil droplet contact angle in the carbonate (from 16.71° to 60.52°) and sandstone (from 8.87° to 50.1°) rock cores. In addition to the 28.6% higher oil recovery in the carbonate core, effective IFT reduction of 74%, and almost optimum mobility ratio (M = 1.01), Chuback exhibited excellent improvement in its rheological properties in the presence of XG, even under high-salinity conditions; its effect was comparable to that of commonly used synthetic surfactants. Thus, in this study, we successfully determined the application of Chuback as a suitable candidate for EOR purposes.

Development and validation of a novel evaporation setup-assisted TLC method with fluorescence detection for determination of flibanserin in pharmaceutical and biological samples

A specific and sensitive thin layer chromatographic method coupled with fluorescence detection for determination of flibanserin (FLN) that treats woman hypoactive sexual desire disorder was developed. The proposed method depends on the enhancement of FLN native fluorescence intensity via the exposure of the developed TLC plate to concentrated hydrochloric acid vapors. Herein, an evaporation setup needed for HCl vapors exposure step was designed for the first time to ensure a uniform distribution of the vapors throughout the developed bands on the plate. Chloroform: methanol (9.5: 0.5, v/v) was the optimum mobile phase that gave a compact band (Rf= 0.44 ± 0.02) using TLC aluminium plates precoated with silica gel G 60F254 as a stationary phase. After exposure of the developed TLC plate to HCl vapors, the FLN bands emission intensities were measured after excitation at 275 nm. Conferring ICH guidelines, the linearity range was 20.0 – 1500.0 ng/band with a good linear relationship (r= 0.9998). Detection and quantitation limits were 5.12 and 15.50 ng/band, respectively. Also, the method was validated for accuracy, precision, robustness, specificity and selectivity. Statistical analysis verified the suitability of the proposed method for estimation of FLN in tablets and in human plasma with acceptable recoveries (98.07–101.45%).