Surfactant Sodium Dodecyl Sulfate Research Articles

Effect of percentage of methanol on micellization position of mixed surfactant interaction in the absence and presence of dye

The interaction behavior of mixed surfactant-dye systems, i.e., anionic surfactant sodium dodecyl sulfate (SDS), cationic surfactant cetyl pyridinium chloride (CPC), and dye methyl orange (MO) was investigated through the allocation of micelles using conductivity measurements. Conductivity as a function of surfactant concentration was monitored to calculate the critical micelle concentration (CMC). The conductivity increased sharply as the surfactant content increased, according to the results. Moreover, the conductivity rises with temperature, whereas it falls with increased methanol (CH3OH). CH3OH-H2O mixed dissolvable media containing 0 %, 10 %, 20 %, and 30 % of CH3OH at 298.15, 308.15, and 318.15 K to work out the basic micelle fixation, gives significant understanding to the arrangement of the mixed surfactants. The CMC and degree of micellar dissociation (α) of SDS with CPC increase in the CH3OH and H2O mixture. The CMC and α values are increased by increasing the temperature. Various thermodynamic parameters, i.e. Standard free energy of micellization (ΔGmo), Standard enthalpy of micellization (ΔHmo), and Standard entropy of micellization (ΔSmo) were computed in SDS-CPC without MO. ΔGmo values for SDS-CPC in the presence of MO results in micellization more probable with MO.

Stability mechanism of viscoelastically enhanced surfactant air foam for low permeability reservoir

Polymer has been widely studied as an effective means to improve foam stability in reservoir exploitation. Nevertheless, the deployment of this technology in low-permeability reservoirs may prove challenging and could potentially result in formation damage. The innovation of this study is the utilization of viscoelastic surfactants to create enhanced air foam with wormlike micelles and three-dimensional network structures. This can result in a synergy between the properties of fluidity control and oil washing efficiency, thereby enhancing the strength of the foam. The supramolecular self-assembly property facilitates the injection of the foam into the formation while preserving its original structure and properties, thereby enhancing the stability of the foam and markedly improving the recovery of low permeability reservoirs. The viscoelastically enhanced air foam system is composed of the zwitterionic surfactant erucylamido propyl betaine (EHSB) and the anionic surfactant sodium dodecyl sulfate (SDS), which has been designated EHSB-SDS. The foam performance was evaluated using the Waring Blender method and rheological behavior, with foam fluid viscosity, initial foam volume (V0), half-life for drainage (td) and foam half-life (tf) serving as the evaluation indicators. The influence of temperature, salinity and oil content on foam performance is considered to explore the reservoir adaptability. The dynamic/micro stability, macro rheological properties, interfacial viscoelasticity and Zeta potential of the enhanced air foam system were further studied to clarify the stability mechanism of enhanced air foam system. The td, tf and composite index of EHSB-SDS is 56.6 min, 36 h and 648000 mL·min, respectively. The viscoelastic surfactants form wormlike micelles, which increase the foam solution viscosity. This results in a slow drainage speed and the rupture of the bubbles. The adsorption of surfactant at the gas/liquid interface results in an increase in surface activity, interfacial expansion modulus and zeta potential, which serves to enhance the strength of the liquid film and the electrostatic repulsion among bubbles. These three factors are primarily responsible for the stability of the foam. The research establishes a theoretical basis for the effective development of low permeability reservoirs and new foam flooding technology.

Solvent-induced modulation of sensitivity and selectivity in the self-assembly of tetracationic cyclophanes with cholesterol sulphate, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate: Observations of significant shifts

Cyclophane CP-1 demonstrates markedly distinct sensitivities toward Cholesterol sulfate (CH-S), Sodium Dodecyl Sulfate (SDS), and Sodium Dodecyl Benzene Sulfonate (SDBS) when the solvent is shifted minimally from a 95 % to a 98 % HEPES-DMSO mixture. In a 98:2 HEPES-DMSO mixture, CP-1 engages in highly selective self-assembly with CH-S, which is characterized by aggregation-induced emission enhancement (AIEE) in contrast to other steroidal sulfates such as pregnenolone sulfate (PRG-S), dehydroisoandrosterone sulfate (DIAND-S), taurocholic acid (TACH-S), and the surfactants SDS and SDBS. This assembly results in an approximate 40-fold increase in fluorescence intensity with three equivalents of CH-S and allows for the detection of concentrations as low as 200 nM under physiological conditions. Dynamic light scattering (DLS) studies illustrate the aggregation of CP-1 and CH-S, with the zeta potential of each shifting from negative values to nearly zero in a 1:2 CP-1:CH-S mixture, indicating self-assembly. This aggregation behavior is reversible, as demonstrated by a corresponding decrease and then increase in fluorescence intensity with temperature variations from 25 °C to 70 °C and back to 25 °C. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analyses show that CP-1 forms aggregates ranging from 100 to 180 nm, which increase to 150–250 nm upon interaction with CH-S. In a 95:5 HEPES-DMSO mixture, CP-1 exhibits a stronger AIEE response with SDS and SDBS compared to CH-S. Cyclophane CP-2, when dissolved in binary DMSO-water mixtures with water content exceeding 80 %, shows similar AIEE phenomena and undergoes selective fluorescence quenching with SDS and only a 50 % increase in fluorescence intensity with CH-S, irrespective of the HEPES concentration (95 % or 98 %).

Monolayer instability of ionic surfactants at the water/air interface due to biosurfactant molecules: A molecular dynamic approach

The decomposition of monolayers prepared with anionic surfactants, sodium dodecyl sulfate (SDS), or cationic ones, dodecyltrimethylammonium bromide (DTAB), at the water/air interface was studied when biosurfactants (surfactin) are added to the films. Molecular dynamics simulations were carried out for monolayers with a fixed number of SDS or DTAB molecules and a different amount of biosurfactants to form SDS/surfactin and DTAB/surfactin mixtures. It is found that the presence of the biosurfactant modifies interfacial and structural properties of the ionic monolayers at the interface; the DTAB monolayer is distorted even for a few surfactin molecules, whereas the SDS monolayer remains steady up to a given amount of biosurfactant. In both monolayers the surface tension decreases with the number of biosurfactants, however while for the DTAB/surfactin the values seem to fluctuate, for the SDS/surfactin mixture the values decay linearly, with a discontinuity for a given surfactin concentration. The linear behaviour of the surface tension for the SDS/surfactin allows us to evaluate free energies for the monolayers and a two-dimensional equation of state. The structure of the monolayers was analyzed in terms of density profiles, order parameters, thickness of the interfaces and the data show that the DTAB/surfactin is more distorted than the SDS/surfactin by the presence of few surfactin molecules. The results indicate that SDS surfactants are more likely to form longer lasting films with fewer surfactin molecules than DTAB.

Hydrophilic surface-modified titanium-based lithium ion sieve adsorbents for efficient lithium extraction

Titanium-based lithium ion sieve adsorbents (HTOs) are considered among the most promising materials for lithium extraction from aqueous sources. In this study, four surfactants—sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), hydroxypropyl cellulose (HPC), and tannic acid (TA)—were used to surface-etch HTOs, preparing adsorbents with enhanced hydrophilicity at the nanoscale. Correlation studies between the hydrophilicity of the HTO-X and their adsorption performance revealed that all HTO-X had lower contact angles than the unetched counterparts, indicating improved adsorption capacities. Notably, TA plays a synergistic role of “killing two birds with one stone”. The TA-etched HTO-T adsorbent exhibited the lowest contact angle (8.8°) and the highest specific surface area (62.10 m2/g). In a LiCl solution, HTO-T’s adsorption capacity for Li+ reached 33.61 mg/g, a 26 % increase over the unetched HTO adsorbent (26.56 mg/g). Simultaneously, HTO-T significantly reduces the adsorption time and enhances the adsorption efficiency during the surface diffusion phase. Additionally, HTO-T demonstrated remarkable selectivity for lithium ions, with separation factors α(Li/Na), α(Li/K), α(Li/Mg), and α(Li/Ca) of 397.13, 181.55, 1288.47, and 1345.19, respectively, showcasing an excellent separation effect. The adsorption mechanism indicates that Li+ adsorption by HTO-T primarily occurs through the disruption of O–H bonds and the formation of new O-Li bonds. This research presents an efficient strategy for the development of HTOs, demonstrating HTO-T as a potential adsorbent for lithium recovery from brine sources.

Performance evaluation of hybrid electrochemical oxidation and ultraviolet light-based persulfate process for the abatement of sodium dodecyl sulfate from wastewater.

The application of hybrid advanced oxidation processes (AOPs) is an efficacious way to remediate emerging contaminants from wastewater. In the present research work, a hybrid electrochemical oxidation and ultraviolet light-based persulfate activation processes (EO-UV/PS) were used to efficiently degrade sodium dodecyl sulfate (SDS) surfactant from synthetic and municipal wastewater. By operating the EO-UV/PS at optimum operating conditions at pH of 7.0, NaCl of 0.02M, current density of 6.4mA/cm2, persulfate dose of 2.5mM, and operating period of 180min, about 94.5 ± 2.8% of SDS (20mg/L) removal was achieved from synthetic wastewater. The abetment of SDS in both EO and UV/PS obeyed pseudo-first-order kinetics with a rate constant of 0.012 and 0.019min-1, respectively. Moreover, the economic analysis revealed 0.23 $ m-3order-1 as the operating cost for degrading SDS in EO-UV/PS. The degradation pathway experimentation suggested the generation of lauric acid by-product during SDS abatement. Besides, nearly 89.3 ± 2.9% of SDS and 58.7 ± 2.4% of total organic carbon reduction was also achieved from real municipal wastewater. Phytotoxicity test on Vigna radiata affirms the non-toxic nature of the EO-UV/PS effluent.

Thermoascus aurantiacus harbors an esterase/lipase that is highly activated by anionic surfactant

Fungal lipolytic enzymes play crucial roles in various lipid bio-industry processes. Here, we elucidated the biochemical and structural characteristics of an unexplored fungal lipolytic enzyme (TaLip) from Thermoascus aurantiacus var. levisporus, a strain renowned for its significant industrial relevance in carbohydrate-active enzyme production. TaLip belongs to a poorly understood phylogenetic branch within the class 3 lipase family and prefers to hydrolyze mainly short-chain esters. Nonetheless, it also displays activity against natural long-chain triacylglycerols. Furthermore, our analyses revealed that the surfactant sodium dodecyl sulfate (SDS) enhances the hydrolytic activity of TaLip on pNP butyrate by up to 5.0-fold. Biophysical studies suggest that interactions with SDS may prevent TaLip aggregation, thereby preserving the integrity and stability of its monomeric form and improving its performance. These findings highlight the resilience of TaLip as a lipolytic enzyme capable of functioning in tandem with surfactants, offering an intriguing enzymatic model for further exploration of surfactant tolerance and activation in biotechnological applications.

Isothiocyanate-Based Microemulsions Loaded into Biocompatible Hydrogels as Innovative Biofumigants for Agricultural Soils.

Biofumigation was proposed as an alternative to synthetic pesticides for the disinfection of agricultural soils, in view of the biocidal effect of isothiocyanates (ITCs) released by some vegetal species, like Brassicaceae. However, biofumigation also presents limitations; thus, a novel and viable alternative could be the direct introduction of ITCs into agricultural soils as components loaded into biodegradable hydrogels. Thus, in this work, ITCs-based microemulsions were developed, which can be loaded into porous polymer-based hydrogel beads based on sodium alginate (ALG) or sodium carboxymethyl cellulose (CMC). Three ITCs (ethyl, phenyl, and allyl isothiocyanate) and three different surfactants (sodium dodecylsulfate, Brij 35, and Tween 80) were considered. The optimal system was characterized with attenuated ATR-FTIR spectroscopy and differential scanning calorimetry to study how the microemulsion/gels interaction affects the gel properties, such as the equilibrium water content or free water index. Finally, loading and release profiles were studied by means of UV-Vis spectrophotometry. It was found that CMC hydrogel beads showed a slightly more efficient profile of micelles' release in water with respect to ALG beads. For this reason, and due to the enhanced contribution of Fe(III) to their biocidal properties, CMC-based hydrogels are the most promising in view of the application on real agricultural soils.

Self-assembly of mixed surfactants sodium dodecylsulfate and polyethylene glycol dodecyl ether in aqueous solutions

The thermodynamic behavior of mixed systems containing the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant polyethylene glycol dodecyl ether (Brij L4) in aqueous solutions was investigated. Electrical conductivity and interfacial tension measurements were employed to investigate the concentration-dependent properties of these surfactant mixtures. Two main experiments were conducted: i) constant ratio experiment: the overall surfactant concentration was varied while maintaining a fixed ratio between SDS and Brij L4. It was shown that the critical micelle concentration (CMC) determined from electrical conductivity measurements does not indicate the formation of the first mixed micelles as observed using tensiometry, but the point from which the adsorption of counterions by the existing micelles became important. By using the Regular Solution Theory (RST), it was found that the interaction between SDS and Brij L4 is synergistic, driven by dipole-ion interactions of the hydrophilic regions of the two surfactants. ii) Fixed SDS concentration while increase the Brij L4 concentration: the resulting electrical conductivity exhibited non-trivial behavior which complexity arose from simultaneous phenomena of incorporation of free SDS molecules into the micelles as Brij L4 concentration increased, leading to a decrease in electrical conductivity; liberation of some adsorbed counterions from the mixed micelles to the solution, which increases the conductivity and increase of viscosity due to Brij L4 further addition that leads to a sequential decrease in electrical conductivity.

Experimental analysis and comparison of thermophysical properties of the three different hybrid nano-catalyst blended diesel fuels

ABSTRACT In this study various hybrid nanofluids were synthesized and investigated to evaluate the different thermophysical and heat transfer properties of nanoparticle suspension-based diesel fuel (DF). The experiments were performed to measure the thermophysical properties of several hybrid nanofluids containing nanoparticles of CuO-Al2O3, Gr-Al2O3 and CuO-Gr with surfactant Sodium Dodecyl Sulphate (SDS). Five nanofluids were synthesized at 5, 44, 102, 160 and 200 mg/l with 1-3% of SDS. The experimental results indicate significant improvements in heat transfer properties with the use of CuO-Al2O3, Gr-Al2O3 and CuO-Gr based nanodiesel test fuels compared to conventional diesel fuel. The thermal conductivity improved by 16.2%-29.5% while specific heat decreased by 3.5% -5.5%. The addition of a surfactant efficiently reduces the increase in viscosity which rises with nanoparticle concentration by 10%-17.5% respectively. Increased heat transport capacities are indicated by an 7-11% rise in the Nusselt number at the different mass concentrations. CuO-Gr hybrid nano-diesel shows encouragingly better results in thermal study that had the most significant modifications. This particular combination is the most promising for heat transfer applications because the heat transfer coefficient also significantly improves by 14-18% at a Reynolds number of 5474. Prandtl number of the CuO-Gr nano-diesel interestingly drops by 5.5%.

Highly 002-Oriented Dendrite-Free Anode Achieved by Enhanced Interfacial Electrostatic Adsorption for Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (AZIBs) are gaining recognition as promising next-generation energy storage solution, due to their intrinsic safety and low cost. Nevertheless, the advancement of AZIBs is greatly limited by the abnormal growth of zinc dendrites during cycling. Electrolyte additives are effective at suppressing zinc dendrites, but there is currently no effective additive screening criterion. Herein, we propose employing the interfacial electrostatic adsorption strength of zinc ions for the initial screening of additives. Subsequently, dendrite-free plating is achieved by employing the anionic surfactant sodium dodecyl benzenesulfonate (SDBS) to enhance electrostatic adsorption. The cycled zinc anode exhibited a dense plating morphology and a high (002) orientation (I002/I101 = 22). The Zn||MnO2 full cell with SDBS exhibited a capacity retention of 85% after 1000 cycles at 1 A g-1. Furthermore, an instantaneous nucleation model and continuous nucleation model (CNM) are constructed to reveal the microscale plating/stripping dynamics under the scenarios of weak adsorption and strong adsorption. The CNM accurately explains the self-optimizing reconstruction of electrodes resulting from enhanced electrostatic adsorption. Our exploration was extended to other anionic surfactants (sodium dodecyl sulfate and disodium laureiminodipropionate), confirming the effectiveness of strong electrostatic adsorption in the screening of electrolyte additives.

Molecular interactional study of SDS and CTAB in aqueous medium of anti-HIV drugs (Emtricitabine and Lamivudine) at different temperatures: A physicochemical investigation

The present study deals with the interactions of Emtricitabine and Lamivudine (anti-HIV drugs) with anionic surfactant sodium dodecylsulphate (SDS) and cationic surfactant cetyltrimethylammonium bromide (CTAB) at (298.15–313.15) K temperature range by volumetry, compressibility and viscometric approach. The experimental values of sound velocity and density are used to compute various parameters such as apparent molar volume (φv), isentropic compressibility (κs), and apparent molar adiabatic compression (φκ) by employing cosphere overlap model. Relative viscosity parameter (ηr) evaluated from viscosity data also helps to understand various interactions prevalent in surfactant-drug-water ternary system. This attempt of extracting information about various physicochemical interactions of anti-HIV drugs with surfactants can prove beneficial to develop novel anti-HIV agents with better viral resistance activity.

Role of surfactants in the degradation and sustainable dyeing for reactive dyeing wastewater

To enhance the decolorization rate of thermally activated sodium persulfate in dye wastewater, C.I. Reactive Black 5 (RB5) was investigated in this study, which was evaluated by the decolorization of the dye solution. The effect of surfactant concentration (including anionic surfactant sodium dodecyl sulfate (SDS), nonionic surfactant Tween 80 (TW-80) and amphoteric surfactant (BS-12)), SPS concentration, and reaction temperature on the degradation of RB5 was studied. Furthermore, the relationship between free radicals and RB5 degradation was investigated. The results showed that the addition of SDS and TW-80 would inhibit the decolorization of RB5. Correspondingly, the effect would enlarge as the surfactant concentration increased. Nevertheless, the addition of BS-12 wouldn’t affect the final decolorization of RB5 dye solution, despite it could increase the decolorization rate in the initial stage. After 10 min of decolorization, compared to the dye liquor without BS-12, the decolorization could increase by 9.07 % and 0.69 %, respectively, after adding 0.5 and 1.0 CMC of BS-12. Besides, when reactive dyes were degraded by thermally activated sodium persulfate, the SO4-· and ·OH would work together, and SO4-· played a major role while ·OH played an auxiliary part. When the treated wastewater was used for dyeing, the addition of BS-12 could effectively regulate the dyeing rate. The fixation and K/S value were increased by 1.1 % and 0.20, respectively. Furthermore, the dyed fabrics also exhibited improved uniformity, with negligible differences in color fastness. The effects of adding SDS were similar to BS-12, while it decreased the exhaustion and fixation rate of RB5. In addition, non-ionic TW-80 was unfavorable to dyeing. This work provides a new way for efficient treatment of dyeing wastewater as well as reuse, opening an environmentally friendly treatment concept.

Temperature dependence of the near infrared absorption spectrum of single-wall carbon nanotubes dispersed by sodium dodecyl sulfate in aqueous solution: experiments and molecular dynamics study.

Single-wall carbon nanotubes (SWCNT) dispersed in water with the help of sodium dodecyl sulfate (SDS) surfactants exhibit a temperature dependent near infrared (NIR) exciton spectrum. Due to their biocompatibility and NIR spectrum falling within the transparent window for biological tissue, SWCNTs hold potential for sensing temperature inside cells. Here, we seek to elucidate the mechanism responsible for this temperature dependence, focusing on changes in the water coverage of the SWCNT as the surfactant structure changes with temperature. We compare optical absorption spectra in the UV-Vis-IR range and fully atomistic molecular dynamics (MD) simulations. The observed temperature dependence of the spectra for various SWCNTs may be attributed to changes in the dielectric environment and its impact on excitons. MD simulations reveal that the adsorbed SDS molecules effectively shield the SWCNT, with ~ 70% of water molecules removed from the first two adlayers; this coverage shows a modest temperature dependence. Although we are not able to directly demonstrate how this influences the NIR spectrum, this represents a potential pathway given the strong influence of the water environment on the excitons in SWCNTs. Optical absorption measurements were carried out in the UV-Vis-NIR range using a Varian Cary 5000 spectrophotometer in a temperature-controlled environment. PeakFit™ v. 4.06 was used as peak-fitting program in the spectral range 900-1400nm (890-1380meV) as a function of the temperature. Fully atomistic molecular dynamics simulations were conducted using the NAMD2 package. The CHARMM force field comprising two-body bond stretching, three-body angle deformation, four-body dihedral angle deformation, and nonbonded interactions (electrostatic and Lennard-Jones 6-16 potentials) was employed.

Formation and survival of clay-mediated protocell membranes composed of single-chain amphiphiles in aqueous solutions

Protocell compartments composed of simple amphiphilic molecules could have survived on the clay mineral surfaces which can serve well as plausible sites for prebiotic chemistry on the early Earth. Herein we chose four common single-chain amphiphiles (SCAs), including the anionic surfactant sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS), the cationic surfactant dodecyltrimethylammonium bromide (DTAB) and the zwitterionic lauryl sulfobetaine (LSB)), as model constituents of early membranes to establish a tentative model for protocell compartment. Positively charged Mg2Al-/Mg2Fe-layered double hydroxides (LDHs) and FeS2 are viewed as models of clay minerals. We demonstrate by comprehensively experimental study that unconventional vesicles can be easily promoted in a SCA aqueous micellar solution in the presence of model particles. Morphology evolutions are traced by collecting samples from mixtures of LDHs and SCA aqueous solutions and then recording at different incubation times via negative-staining or cryo-transmission electron microscopy (NS-TEM or cryo-TEM) and dynamic light scattering (DLS). Additionally, the stability of SCA bilayer membranes under possible prebiotic environment are tentatively studied. This work not only offers a robust yet versatile approach for the fabrication of novel vesicles but also provides new insights into the origin of cellular life.

Thermodynamic characteristics and surface free energy analysis of bifonazole and lecithin with sodium dodecyl sulfate in hydroethanolic solvent systems

The thermodynamic investigations of the well-recognised antifungal drug bifonazole and lecithin with anionic surfactant sodium dodecyl sulphate have been established. The experiments were conducted using five distinct hydro-ethanolic concentrations, namely 0% v/v, 10% v/v, 30% v/v, 70% v/v, and 90% v/v ethanol, throughout a range of five temperatures (ranging 20 ℃, 25 ℃, 30 ℃, 35 ℃ and 40 ℃) with an increment of drug concentration. The study involved the determination of several parameters, including surface tension (σ), density (ρ), conductivity (κ), contact angle (θ) and surface free energy. Conductivity and surface tension data was used for calculating critical micelle concentration (CMC). CMC was utilised to calculate various thermodynamic properties, such as the standard entropy change (ΔS°m), standard Gibbs energy change (ΔG°m) and standard enthalpy change (ΔH°m) of micellization. This study represents a comparative analysis of the critical micelle concentration (CMC) by utilising surface tension and conductivity measurements. Contact angle is used to determine the hydrophobicity and hydrophilicity of the system. These investigations are valuable for examining the magnitude of hydrophobic interactions within the system, which might be used to ascertain an optimal concentration of bifonazole, lecithin and surfactant to prepare ethosomal formulations.

The role of the cation and anion in aqueous liquid chromatography with sodium dodecyl sulphate and imidazolium-based ionic liquids as mobile phase reagents

BackgroundIn reversed-phase liquid chromatography, solute retention is primarily influenced by interactions between a nonpolar stationary phase and a moderately polar hydro-organic mobile phase, based on the solute lipophilicity. However, challenges regarding retention and peak tailing can arise due to ionic interactions between positively charged analytes and free silanols present on silica-based stationary phases. To address these challenges, incorporating surfactants and ionic liquids (ILs) into the mobile phase offers an effective solution. These additives synergistically enhance chromatographic performance through electrostatic and lipophilic interactions, which enable fine-tuning of selectivity and improved separation efficiency. ResultsThis study explores the chromatographic behaviour of several basic compounds in aqueous mixtures containing the anionic surfactant sodium dodecyl sulphate (SDS), above its critical micellar concentration, combined with various 1-alkyl-3-methylimidazolium-based ionic liquids (ILs) featuring chloride, tetrafluoroborate, and hexafluorophosphate anions, all without the addition of organic solvents. Specifically, this research investigates the influence of different anion types within the ILs and considers the impact of the IL cations. Analysis of solute peak profiles reveals narrow and symmetrical peaks. By introducing tetrafluoroborate and hexafluorophosphate IL anions into a mobile phase that contains an anionic surfactant, the study sheds light on the interactions occurring within the chromatographic column. This enhanced understanding of the combined effects of surfactants and ILs contributes to refining chromatographic methodologies. SignificanceThis research highlights the importance of carefully selecting the appropriate IL when incorporating it into a micellar mobile phase alongside SDS. This combination results in practical retention times that surpass the performance achieved with either the surfactant or IL alone in the mobile phase. The study particularly emphasises the impact of the IL anion, especially in the absence of SDS and organic solvents. This unveils interactions that are otherwise obscured in micellar and hydro-organic media, providing new insights into chromatographic dynamics.

Green and sensitive detection of olopatadine in aqueous humor using a signal-on fluorimetric approach: GREEnness assessment.

Olopatadine (OLP) is widely utilized as an effective antihistaminic drug for alleviating ocular itching associated with allergic conjunctivitis. With its frequent usage in pharmacies, there arises a pressing need for a cost-effective, easily implementable, environmentally sustainable detection method with high sensitivity. This study presents a novel signal-on fluorimetric method for detecting OLP in both its pure form and aqueous humor. The proposed approach depends on enhancing the weak intrinsic fluorescence emission of OLP, achieving a remarkable increase of up to 680% compared to its intrinsic fluorescence. This enhancement is achieved by forming micelles around protonated OLP using an acetate buffer (pH 3.6) and incorporating a solution of sodium dodecyl sulfate (SDS) surfactant. A strong correlation (R = 0.9996) is observed between the concentration of OLP and fluorescence intensities ranging from 1.0 to 100.0 ng mL-1 with a limit of detection of 0.22 ng mL-1. This described method is successfully employed for quantifying OLP in both its powder form and pharmaceutical eye drops. Furthermore, it demonstrates robust performance in determining OLP in artificial aqueous humor with a percentage recovery of 99.05 ± 1.51, with minimal interference from matrix interferents. Moreover, the greenness of the described method was evaluated.

Mesoporous pineapple crown-derived activated carbon modified matrix for the detection of carbendazim in the presence of anionic surfactant

Carbon paste electrodes (CPEs) are commonly employed in electroanalysis because of their chemical stability, broad electrochemical window, low capacitive current, ease of fabrication, and surface renewability. Electrocatalysts can easily be embedded into CPEs to make them suitable for a variety of applications. Poor biowaste management presents a significant challenge in the agro-industry and agriculture due to the rapid decomposition of biowaste, driven by its high water content and limited biological stability, which leads to pest attraction and greenhouse gas emissions. Consequently, this green waste can be utilized for the development of electrocatalysts. Activated carbon (AC) has been utilized in progressive electrochemical applications as it exhibits high conductivity and porosity that help to enhance electrocatalytic activity. Herein, pineapple fruit crown (PC) peel-derived AC (PCAC) is utilized as the sensing material for the determination of fungicide, carbendazim (CBM). The synthesized material was characterized using SEM, FT-IR, XRD, EDX, AFM, CV and EIS. Besides, to enhance the surface properties, Sodium dodecyl sulfate (SDS) surfactant is used as a mediator in detecting CBM. The CV and SWV approaches were employed to assess the electrochemical response of the developed electrodes for the CBM determination. Under optimum experimental conditions, the SDS/PCAC/CPE exhibits low DLim and QLim values of 32.0 nM and 128.0 nM with considerable selectivity. Furthermore, the SDS/PCAC/CPE was employed in real-time analysis of CBM in spiked environmental samples, which showed satisfying recovery results. Moreover, the electrode showed good stability over multiple measurements, and these results demonstrate that SDS/PCAC/CPE is a promising sensor for CBM detection.

Voltammetric determination of the antifungal drug posaconazole in the presence of an anionic surfactant on a boron-doped diamond electrode

This study describes a new, fast and simple procedure of electrochemical assay of posaconazole (PCZ), which is currently regarded as one of the most important antifungal agents, recommended in the treatment of systemic infections, effective even against rare and atypical kinds of fungi. PCZ is very effective and safe, displaying much lower toxicity than other traditional antifungal drugs. A new, attractive procedure of assaying the compound on boron-doped diamond (BDD) electrode after cathodic pretreatment in the presence of sodium dodecyl sulfate (SDS) is presented in the work. The anionic surfactant SDS was selected after the comparative analysis of various cationic surfactants. PCZ gave a single irreversible oxidation peak at the potential of 0.59 V. The addition of SDS resulted in an almost 5-fold growth in the value of recorded currents as compared to those observed in the absence of the surfactant. The highest peak was obtained in Britton-Robinson buffer at pH 3.78. The calibration curve of PCZ plotted using the SWV technique was linear in the concentration range from 1.34·10−8 mol/L to 1.44·10−6 mol/L. The limit of detection and limit of quantification were 3.78·10−9 mol/L and 1.14·10−8 mol/L, respectively. The value of relative standard deviation of the measurements did not exceed 4.42 %, which proves good precision of the proposed method. The proposed procedure was successfully used in assaying PCZ in simulated gastric juice.