Phase Transfer Research Articles

A Twin Spiral Coil Phase Transfer Heat Exchanger for Storing Heat Should Be Designed and Tested in The Lab.

Abstract This in-depth study of thermal energy storage (TES) systems examines their function in resolving time, temperature, power, and location problems within the immense energy system design. With its incredible growth, TES creates a shadow over the future, projecting optimism for a better economy and more reliable energy infrastructure. The study is concentrated on a state-of-the-art heat exchanger that has circular double coils with various diameters, with a reliance on charging process amplification. The trial stage is decorated like a well-coordinated ensemble, integrating shell-and-tube design together with intense evaluation of varied tube morphologies, HTF flow designs, and protecting processes. The TES device effortlessly reveals its many components, such as a gas heater, control valves, a pump, a circular container with spiral HTF tubes, and a chorus of music. The PCM heat storage unit’s performance improved in two resonant cases that evaluated the effect of the HTF input temperature and coil charge in great detail. Case 2 and Case 1’s connections exhibit the significant heat absorption and PCM liquification by creating a web of various temperature differences while charging. With its improved temperature performance and straightforward design, Case 2 displays rapid removal and quicker charging periods. In addition, the study examines the HTF input parameters, which cast light on the constant HTF departure temperatures and demonstrate the importance of temperature during the charging opera. While the total energy storage rate rises with increasing temperatures, the expected scores are in accord with the mood fluctuations at the beginning and end of HTF. This review functions as a folder of vital insights, analyzing notes towards constructing PCM charging processes for higher energy storage efficiency - ultimately placing a limelight on the endless possibilities that TES systems predict in the present spectrum of energy uses.

Получение экологичного катализатора на основе четвертичной аммониевой соли гетерополикислоты для глубокой окислительной десульфуризации дизельного топлива

Hydrodesulfurization (HDS) is the most widely used method for fuel oil desulfurization, which can easily remove mercaptan and thiophene from diesel oil, but the removal rate of dibenzothiophene (DBT) and its alkylated derivatives is low. Compared with traditional HDS technology, oxidative desulfurization (ODS) technology has the advantages of less investment, mild reaction conditions, and high ODS activity for DBT and its derivatives. Heteropoly acid (salt)/H2O2 system is highly efficient and the oxidation product of hydrogen peroxide is water, making them green catalysts. A new type of polyoxometalates phase transfer catalyst, [(C16H33(CH3)3)N]3-HPW11VO40, was synthesized through ion exchange method. It was applied to the catalytic oxidative desulfurization of model diesel oil using H2O2 as oxidant. The influencing factors of reaction were investigated in detail. The catalyst exhibits the dibenzothiophene conversion rate of 100% and excellent reusability and retrievability with 99.97% conversion after five times reaction in mild reaction conditions of n(catalyst)/n(DBT)=1/80, n(H2O2)/n(DBT)=8/1, 50 °C, and atmospheric pressure in 3 h. The catalyst could be quickly separated and recycled by centrifugation after reaction and hence be promising in the low-sulfur fuel production.

An Innovative Approach for Oxidative Desulfurization Advancement through High Shear Mixing: An Optimization Study on the Application of Benzothiophene.

Alternative fuels are being explored to mitigate the effects of petroleum-based fuels. Pyrolysis oil from waste tires is a promising alternative fuel; however, it contains very high concentrations of benzothiophene (BT) which are beyond the allowable sulfur limits of Taiwan and the Philippines. Mixing-assisted oxidative desulfurization (MAOD) is a method that removes sulfur from fuel oils by utilizing high-shear mixing and oxidants. In this paper, the oxidation of BT in a model fuel was studied to determine optimal process conditions. Crude Fe(VI) prepared from sludge was used as the oxidant. Using the Box-Behnken design under response surface methodology, the significance of the following independent variables was studied: mixing speed (4400-10 800 rpm), phase transfer agent (PTA) amount (100 to 300 mg), Fe(VI) concentration (400-6000 ppm), and mixing temperature (40 to 60 °C). The results from a comprehensive statistical analysis showed the increase of sulfur conversion with high levels of Fe(VI) concentrations and PTA amounts together with low levels of agitation speeds and temperatures. The BT to BT sulfone conversions from experimental runs ranged from 17% to 64%. The optimum sulfur conversion of 88% for the BT model fuel was reached at the maximum levels of Fe(VI) concentration and mixing speed, along with the minimum levels of PTA concentration and temperature. The optimal MAOD variables were applied to a high-sulfur pyrolysis oil sample, which resulted in a sulfur reduction of 55%. The produced fuel oil meets the sulfur requirements of Taiwan and the Philippines for industrial heating oils. Therefore, the findings of the study support the effectiveness of sludge-derived Fe(VI) in the MAOD of BT in the model fuel and pyrolysis oil under mild process conditions.

Dynamic evolution of frontal-temporal network connectivity in temporal lobe epilepsy: A magnetoencephalography study.

Temporal lobe epilepsy (TLE) frequently involves an intricate, extensive epileptic frontal-temporal network. This study aimed to investigate the interactions between temporal and frontal regions and the dynamic patterns of the frontal-temporal network in TLE patients with different disease durations. The magnetoencephalography data of 36 postoperative seizure-free patients with long-term follow-up of at least 1 year, and 21 age- and sex-matched healthy subjects were included in this study. Patients were initially divided into LONG-TERM (n = 18, DURATION >10 years) and SHORT-TERM (n = 18, DURATION ≤10 years) groups based on 10-year disease duration. For reliability, supplementary analyses were conducted with alternative cutoffs, creating three groups: 0 < DURATION ≤7 years (n = 11), 7 < DURATION ≤14 years (n = 11), and DURATION >14 years (n = 14). This study examined the intraregional phase-amplitude coupling (PAC) between theta phase and alpha amplitude across the whole brain. The interregional directed phase transfer entropy (dPTE) between frontal and temporal regions in the alpha and theta bands, and the interregional cross-frequency directionality (CFD) between temporal and frontal regions from the theta phase to the alpha amplitude were further computed and compared among groups. Partial correlation analysis was conducted to investigate correlations between intraregional PAC, interregional dPTE connectivity, interregional CFD, and disease duration. Whole-brain intraregional PAC analyses revealed enhanced theta phase-alpha amplitude coupling within the ipsilateral temporal and frontal regions in TLE patients, and the ipsilateral temporal PAC was positively correlated with disease duration (r = 0.38, p <.05). Interregional dPTE analyses demonstrated a gradual increase in frontal-to-temporal connectivity within the alpha band, while the direction of theta-band connectivity reversed from frontal-to-temporal to temporal-to-frontal as the disease duration increased. Interregional CFD analyses revealed that the inhibitory effect of frontal regions on temporal regions gradually increased with prolonged disease duration (r = -0.36, p <.05). This study clarified the intrinsic reciprocal connectivity between temporal and frontal regions with TLE duration. We propose a dynamically reorganized triple-stage network that transitions from balanced networks to constrained networks and further develops into imbalanced networks as the disease duration increases.

Electrophysiological dynamics of salience, default mode, and frontoparietal networks during episodic memory formation and recall: A multi-experiment iEEG replication.

Dynamic interactions between large-scale brain networks underpin human cognitive processes, but their electrophysiological mechanisms remain elusive. The triple network model, encompassing the salience (SN), default mode (DMN), and frontoparietal (FPN) networks, provides a framework for understanding these interactions. We analyzed intracranial EEG recordings from 177 participants across four diverse episodic memory experiments, each involving encoding as well as recall phases. Phase transfer entropy analysis revealed consistently higher directed information flow from the anterior insula (AI), a key SN node, to both DMN and FPN nodes. This directed influence was significantly stronger during memory tasks compared to resting-state, highlighting the AI's task-specific role in coordinating large-scale network interactions. This pattern persisted across externally-driven memory encoding and internally-governed free recall. Control analyses using the inferior frontal gyrus (IFG) showed an inverse pattern, with DMN and FPN exerting higher influence on IFG, underscoring the AI's unique role. We observed task-specific suppression of high-gamma power in the posterior cingulate cortex/precuneus node of the DMN during memory encoding, but not recall. Crucially, these results were replicated across all four experiments spanning verbal and spatial memory domains with high Bayes replication factors. Our findings advance understanding of how coordinated neural network interactions support memory processes, highlighting the AI's critical role in orchestrating large-scale brain network dynamics during both memory encoding and retrieval. By elucidating the electrophysiological basis of triple network interactions in episodic memory, our study provides insights into neural circuit dynamics underlying memory function and offer a framework for investigating network disruptions in memory-related disorders.

Hydronium Ion Transport across the Liquid/Liquid Interface Assisted by a Phase-Transfer Catalyst: Structure and Thermodynamics Using Molecular Dynamics Simulation.

Molecular dynamics simulations are used to examine the thermodynamic and structural aspects of the transfer of the classical hydronium ion (H3O+) across a water/1,2-dichloroethane (DCE) interface assisted by the phase-transfer catalyst (PTC) tetrakis(pentafluorophenyl) borate anion (TPFB-). The free energy of transfer from water to DCE of the H3O+-TPFB- ion pair is calculated to be 6 ± 1 kcal/mol, significantly less than that of the free hydronium ion (17 ± 1 kcal/mol). The ion pair is relatively stable at the interface and in the organic phase when it is accompanied by three water molecules with a small barrier to dissociation that supports its utility as a PTC. An examination of the hydration structure that accompanies the transfer of the ion pair shows that the ion pair, like the free hydronium ion, is transferred with the assistance of a finger-like water structure.

Cortical Connectivity Response to Hyperventilation in Focal Epilepsy: A Stereo-EEG Study

Hyperventilation (HV) is an activation technique performed during clinical practices to trigger epileptiform activities, supporting the neurophysiological evaluation of patients with epilepsy. Although the role of HV has often been questioned, especially in the case of focal epilepsy, no studies have ever assessed how cortical structures respond to such a maneuver via intracranial EEG recordings. This work aims to fill this gap by evaluating the HV effects on the Stereo-EEG (SEEG) signals from a cohort of 10 patients with drug-resistant focal epilepsy. We extracted multiple quantitative metrics from the SEEG signals and compared the results obtained during HV, awake status, non-REM sleep, and seizure onset. Our findings show that the cortical connectivity, estimated via the phase transfer entropy (PTE) algorithm, strongly increases during the HV maneuver, similar to non-REM sleep. The opposite effect is observed during seizure onset, as ictal transitions involve the desynchronization of the brain structures within the epileptogenic zone. We conclude that HV promotes a conductive environment that may facilitate the propagation of epileptiform activities but is not sufficient to trigger seizures in focal epilepsy.

Hydrophobic iron oxide nanoparticles: Controlled synthesis and phase transfer via flash nanoprecipitation

Iron oxide nanoparticles (IONPs) synthesized via thermal decomposition find diverse applications in biomedicine owing to precise control of their physico-chemical properties. However, use in such applications requires phase transfer from organic solvent to water, which remains a bottleneck.Through the thermal decomposition of iron oleate (FeOl), we systematically investigate the impact of synthesis conditions such as oleic acid (OA) amount, temperature increase rate, dwell time, and solvent on the size, magnetic saturation, and crystallinity of IONPs. Solvent choice significantly influences these properties, manipulating which, synthesis of monodisperse IONPs within a tunable size range (10-30 nm) and magnetic properties (75 to 42 Am2Kg-1) is obtained.To enable phase transfer of IONPs, we employ flash nanoprecipitation (FNP) for the first time as a method for scalable and precise size control, demonstrating its potential over conventional methods. Poly(lactic-co-glycolic acid) (PLGA)-coated IONPs with hydrodynamic diameter (Hd) in the range of 250 nm, high colloidal stability and high IONPs loadings up to 43% were obtained, such physicochemical properties being tuned exclusively by the size and hydrophobicity of starting IONPs. They showed no discernible cytotoxicity in human dermal fibroblasts, highlighting the applicability of FNP as a novel method for the functionalization of hydrophobic IONPs for biomedicine.

Detection and diagnosis of diabetic eye diseases using two phase transfer learning approach.

Early diagnosis and treatment of diabetic eye disease (DED) improve prognosis and lessen the possibility of permanent vision loss. Screening of retinal fundus images is a significant process widely employed for diagnosing patients with DED or other eye problems. However, considerable time and effort are required to detect these images manually. Deep learning approaches in machine learning have attained superior performance for the binary classification of healthy and pathological retinal fundus images. In contrast, multi-class retinal eye disease classification is still a difficult task. Therefore, a two-phase transfer learning approach is developed in this research for automated classification and segmentation of multi-class DED pathologies. In the first step, a Modified ResNet-50 model pre-trained on the ImageNet dataset was transferred and learned to classify normal diabetic macular edema (DME), diabetic retinopathy, glaucoma, and cataracts. In the second step, the defective region of multiple eye diseases is segmented using the transfer learning-based DenseUNet model. From the publicly accessible dataset, the suggested model is assessed using several retinal fundus images. Our proposed model for multi-class classification achieves a maximum specificity of 99.73%, a sensitivity of 99.54%, and an accuracy of 99.67%.

Dimerization of perfluoropropyl vinyl ether during the pyrolysis of hexafluoropropylene oxide dimer

Dimerization of perfluoropropyl vinyl ether (PPVE) generally reduces its yield and selectivity during the pyrolysis of hexafluoropropylene oxide dimer ((HFPO)2). However, the mechanism of PPVE dimerization is not well understood. In this paper, the PPVE dimer was obtained during the pyrolysis of (HFPO)2. Subsequently, the chemical structure of PPVE dimer was further determined by gas chromatography-mass spectrometry (GC–MS) and nuclear magnetic resonance (NMR). The results showed that the concentration of PPVE dimer rises in proportion to the extended reflux time of PPVE in the reaction system. Based on the experimental phenomenon, a possible generation mechanism of PPVE dimer was then proposed, and the possibility of the generation pathway was further verified in combination with density functional theory (DFT). In addition, to effectively reduce the production of PPVE dimer, crown ethers and quaternary ammonium salts were added to the reaction system as phase transfer catalysts. Among them, the phase transfer catalyst (15-crown-5) was more effective and reduced the PPVE dimer content from 1.34 % to 0.31 %. This work provides an idea to inhibit the dimerization of PPVE and increase the yield and selectivity of PPVE.

Enantioselective S‐Alkylation of Sulfenamides by Phase‐Transfer Catalysis

AbstractA general phase‐transfer catalyst (PTC) mediated enantioselective alkylation of N‐acylsulfenamides is reported. Essential to achieving high selectivity was the use of the triethylacetyl sulfenamide protecting group along with aqueous KOH as the base under biphasic aqueous conditions to enable the reaction to be performed at −40 °C. With these key parameters, enantiomeric ratios up to 97.5 : 2.5 at the newly generated chiral sulfur center were achieved with an inexpensive cinchona alkaloid derived PTC. Broad scope and excellent functional group compatibility was observed for a variety of S‐(hetero)aryl and branched and unbranched S‐alkyl sulfenamides. Moreover, to achieve high selectivity for the opposite enantiomer, a pseudoenantiomeric catalyst was designed and synthesized from inexpensive cinchonidine. Given that sulfoximines are a bioactive pharmacophore of ever‐increasing interest, selected product sulfilimines were oxidized to the corresponding sulfoximines with subsequent reductive cleavage affording the free‐NH sulfoximines in high yields. The utility of the disclosed method was further demonstrated by the efficient asymmetric synthesis of atuveciclib, a phase I clinical candidate for which only chiral HPLC separation had previously been reported for isolation of the desired (R)‐sulfoximine stereoisomer.

High-fidelity transfer of helical phase via hyper-Raman scattering in a monolayer graphene

Graphene is a fascinating two-dimensional optical material with a unique electronic band structure and a giant optical nonlinearity under the action of a strong magnetic field. Here we propose a scheme to transfer helical phase of the orbital angular momentum (OAM) light via hyper-Raman scattering in a monolayer graphene assisted by a magnetic field. Due to the unique electronic properties and selection rules near the Dirac point, it is found that high-fidelity transfer of phase structure and, in particular, of OAM from a pump field to the Raman field generated in a hyper-Raman scattering process occurs under the resonance condition. Interestingly, the obtained results allow us to control the intensity of Raman field with stable phase structure by varying the intensities of two pump fields. Hereby, the mechanism of efficient generation and manipulation of OAM Raman field may have exciting potential applications in the generation of short-wavelength coherent radiation, conversion of frequency as well as nonlinear spectroscopy in graphene materials.

Phase Transfer Catalysis: New Technology to Boost Organic Farming

Introduction of Phase Transfer Catalysis (PTC) technology, which was developed in the 1970s has revolutionised the dyes and pharmaceutical industries in many ways. PTC is a process that facilitates the organic compounds to move from one phase to another phase, without any change in the chemical qualities. Application of this technology was explored in the 1980s for agriculture, by using different plant extracts as PT catalysts. The objective was to facilitate increased absorption of nutrients by plants, by stimulating plant growth and easy availability of nutrients in the soil. Introduction of nano-carbon materials with nutrients and herbal growth stimulants could further support the crop growth by facilitating increased uptake of nutrients, apart from enabling the plants to develop resilience to harsh environmental conditions, resulting in higher crop yields. Some organic bio-stimulants developed recently by Snehasrusthi Group in India have been very successful in improving the growth, yield and quality of several seasonal and perennial crops in India. These bio-stimulants have excellent potential to boost organic agricultural production and income of farmers in the future.

Jacobi-Fourier phase masks as ophthalmic elements to correct presbyopia.

Investigations into the correction of presbyopia have considered lens design, clinical implications and the development of objective metrics such as the visual Strehl ratio. This study investigated the Jacobi-Fourier phase mask as an ophthalmic element in the correction of presbyopia. The goal was to develop a contact or intraocular lens whose performance was largely insensitive to changes in pupil diameter. Numerical simulations based on Fourier optics were performed to evaluate three different Jacobi-Fourier polynomials, with the aim of providing a range of clear vision (1 Dioptre (D)). Performance was evaluated for three pupil sizes (6, 4 and 2 mm), while polychromatic images were simulated using three different wavelengths (656.3, 587.6 and 486.1 nm). The Neural Transfer function was included in the simulation. To validate the method and results, we used the Visual Strehl combined objective metric (VSCombined) currently used in visual optics. This metric gives more weight to the phase transfer function and is more suitable for non-symmetrical phase functions. Numerical validation showed the suitability of the Jacobi-Fourier phase masks for extending the range of clear vision of presbyopic eyes, providing a visual acuity of at least 0.10 logMAR (6/7.5 Snellen) at all distances between 1 and 6 m. The results show a range of clear vision of 1D was not affected by changes in pupil size, an increase in retinal image contrast accompanied by image artefact reduction by increasing the radial order of the Jacobi-Fourier phase mask and a reduction of wavelength dependence of the retinal images. These results are supported by simulated images and the objective criterion VSCombined. The use of Jacobi-Fourier phase masks as ophthalmic elements for presbyopic correction show promising results, with a good range of clear vision andreduced dependence on pupil size and chromatic aberration.

Thiocarbohydrazide-cross-linked pectin: A promising support material for palladium nanoparticles in the water-mediated Suzuki-Miyaura cross-coupling reaction and the catalytic reduction of 4-nitrophenol

Suzuki-Miyaura reaction is a classic palladium-catalyzed reaction for forming Csp2-Csp2 bonds. However, the leaching of Pd species and using organic solvents are two important problems that adversely affect their performance, reusability, and greenness. Considering the abundant resources, cheapness, and availability of pectin (Pec), a Pec-based catalyst for the Suzuki reaction in pure water as a non-toxic reaction medium was developed for the first time. In this regard, Pec was chosen as a benign support and cross-linked by thiocarbohydrazide (TCH) to prepare Pec-TCH. The Pec-TCH acted as an efficient reducing and stabilizing agent for in-situ fabrication of Pd(0) nanoparticles. The heterogeneous and air-stable Pec-TCH-Pd(0) nanoparticles were thoroughly characterized. The results exhibited a significant catalytic activity (up to 99%) and reusability (at least 7 times) for in-water Suzuki-Miyaura cross-coupling reaction. The use of TBAB as a phase-transfer catalyst improved the yield of Suzuki reaction since it prevented the problems related to the immiscibility of water and aryl halides as well as the gelation of catalyst. The catalyst was also utilized for water-mediated 4-nitrophenol reduction to 4-aminophenol with NaBH4 which showed excellent activity (k = 9.2 × 10−3 s−1). A very good compatibility with iodobenzene, bromobenzene, and chlorobenzene was observed for the Suzuki reaction. Because of various binding sites such as amino, hydroxyl, carbonyl and thiocarbonyl groups, negligible leach of Pd nanoparticles was observed, as shown by ICP-MS after runing 7th of reusability studies. Moreover, the leaching, mercury poisoning, and large-scale tests showed its potential for industrial applications.

Zirconia Ageing is related to Total Hip Arthroplasty Aseptic Loosening. A Study of 45 Retrieved Zirconia Heads

BackgroundY-TZP zirconia heads were recalled by the Food and Drug Administration (FDA) in 2001 and zirconia alone was no longer used in orthopedics. Tunnel furnace sintering was suspected of producing defects responsible for early material failure. As Zirconia Toughened Alumina (ZTA) matrices are widely used as bearing material and contain zirconia grains, there remains a need to better understand the in vivo ageing process of zirconia and its clinical implications when the material is produced by batch furnace sintering, the validated sintering process. Questions/objectivesIs there an association between the ageing of batch furnace produced zirconia and THA revision? Methods45 retrieved femoral heads, batch furnace sintered only, were analyzed. Roughness was measured by 3D profilometry, phase transfer by µRaman spectroscopy.Clinical data were compared with material characteristics. ResultsIrrespective of the cause of revision, all heads showed a crystallographic phase transition from tetragonal to monoclinic over 19.5%. A correlation was found between the phase change, roughness increase and aseptic loosening, with a threshold set at 24.5% of monoclinic phase. ConclusionsThe ageing process of zirconia may lead to aseptic loosening, which, in the absence of contrary evidence, prohibits its use as the sole component of orthopedic materials. ZTA matrices should be clinically monitored, especially in young patients, and better in vitro modelling needs to be performed. Level of evidenceIV; Case series.

PTC in the polyenolate‐mediated [10+2]‐cycloaddition for the synthesis of α,α‐disubstituted amino acid precursors

Abstract. The manuscript describes a formal [10+2] higher‐order cycloaddition between 2‐benzylideneindan‐1‐ones and α‐alkilidene azlactones as higherene precursors and higherenofiles respectively. The reaction is realized under Brønsted‐base catalysis utilizing the phase transfer catalysis approach. The key intermediate is an isobenzofulvene‐derived polyenolate which acts as a 10‐electron component in the higher‐order cycloaddition. By using this strategy, a series of structurally diverse compounds containing a polycyclic hydrocarbon scaffold was prepared in 79‐99% yields. In addition, the potential of the obtained [10+2]‐cycloadducts has been confirmed by transformations, including the synthesis of a highly‐valuable alpha,alpha‐disubstituted N‐protected alpha‐aminoester.

Catalytic Enantioselective Propargylation of Pyrazolones by Amide-Based Phase-Transfer Catalysts.

In this paper, we developed a highly enantioselective alkylation of 4-substituted pyrazolones catalyzed by phase-transfer catalysis. Cheap halohydrocarbons were employed as electrophilic alkylationg agents, and propargyl, allyl, and benzyl products with all-carbon quaternary stereocenters were afforded with excellent enantioselectivities and good yields. We found that the unique structures of the catalyst (hydrogen bond donors of the C-9 hydroxyl group and amide group, the triphenyl at the NH-position) were important for good enantioselectivity. Furthermore, chiral propargyl products could be easily connected to azide molecules by click cycloaddition, which offers unique opportunities to obtain structurally diverse chiral pyrazolones.

3‑Amino Oxindole Schiff Base Efficiently Paired with p‑Quinone Methide to Enable a New Diastereoselective and Enantioselective 1,6-Conjugated Addition in the Presence of a Cinchonidinium Phase Transfer Catalyst

3‑Amino oxindole Schiff base has been used as an efficient substrate company with p‑quinone methides for a new highly diastereoselective and enantioselective 1,6-conjugate addition in the presence of a O-allyl-N-(9-anthracenylmethyl) cinchonidinium bromide phase transfer catalyst under mild reaction conditions. A broad series of chiral quaternary 3-amino oxindoles with 4-hydroxybenzyl scaffold were smoothly obtained in good to excellent yields with excellent diastereoselectivities (>20:1) and enantioselectivities (up to 99 % ee). A typical scale-up preparation and subsequent hydrolysis of a pyridine substrate was successfully performed and a potential valuable chiral amino-pyridine bifunctional chiral building block was obtained, which is structurally feasible as chiral ligand for asymmetric metallic catalysis.

Solvent-Focused Gas Chromatographic Determination of Thymol and Carvacrol Using Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction through Solidifying Floating Organic Droplets (USA-DLLME-SFO).

An ultrasound-assisted dispersive liquid-liquid microextraction by solidifying floating organic droplets, coupled to a form of temperature-programmed gas chromatography flame ionization detection, has been developed for the extraction and determination of thymol and carvacrol. This method utilizes undecanol as the extraction solvent, offering advantages such as facilitating phase transfer through solidification and enhancing solvent-focusing efficiency. The optimal gas chromatography conditions include a sample injection volume of 0.2 µL, a split ratio of 1:10, and a flow rate of 0.7 mL min-1. The extraction conditions entail an extraction solvent volume of 20 µL, a disperser solvent (acetone) volume of 500 µL, pH 7.0, 7.0% NaCl (3.5 M), a sample volume of 5.0 mL, an ultrasound duration of 10 min, and a centrifuge time of 7.5 min (800 rpm). These conditions enable the achievement of a high and reasonable linear range of 3.5 to 70. 0 μg mL-1 for both thymol and carvacrol. The detection limits are found to be 0.95 and 0.89 μg mL-1, respectively, for thymol and carvacrol. The obtained relative standard deviations, 2.7% for thymol and 2.6% for carvacrol, demonstrate acceptable precision for the purpose of quantitative analysis.