Cloud Point Extraction Research Articles (Page 1)

This study reports on a cloud point extraction (CPE) method devised for the thorough separation, preconcentration, and spectrophotometric estimation of cadmium (Cd(II)) from solutions and food matrices using azo derivatives as complexing agents. The research problem under study concerns the sensitive and selective determination of Cd(II), a heavy metal recognized as toxic due to its profound environmental and health dangers. The specific aim was to optimize and check CPE method reproducibility for the more stable chelation complexes of cadmium (II) 4-((4-hydroxyquinolin-3-yl)diazenyl)benzenesulfonamide (HQDBS) and 3-((1H-indol-5-yl)diazenyl)quinolin-4-ol (IDQ). The optimization was performed by testing the following fundamental parameters: pH, type and volume of surfactant (Triton X-100), extraction temperature, and duration of heating. The maximum absorptions (λmax) of both examined complexes of cadmium with HQDBS and IDQ were found at 478 nm and 499 nm respectively. The spectroscopic methods and field emission scanning electron microscopy (FE-SEM) were applied to structural characterization of the extracted complexes. The developed method was applied to food samples and validated with Flame Atomic Absorption Spectroscopy (FAAS). It was showed that the methods gave highly sensitive and good selective responses which had a strong correlation with the FAAS results. F-test statistical calculations showed that the differences between techniques are insignificant, thus proving the reliability of CPE methodology expected for Cd(II) analytical chemistry. The CPE technique is recommended for determining the presence of Cd(II) in food and environmental samples since it is easy, economical, and less harmful to the environment.

New azo reagent 2-[Benz Thiazol azo]-1 –Dopamine , The reagent was Prepared through a coupled reaction and characterized using spectroscopic methods, including (FTIR) and (UV. –Vis.) is spectroscopy , as well as proton nuclear Magnetic resonance ( HNMR).to verify its chemical identity .This reagent was used to estimate Zinc( II ) ion through the formation of a doubly charged complex, Which was extracted and identified using cloud point extraction(CPE) technique , Optimization conditions and factors affecting is study that effected on extraction Efficiency E%. The measured of spectrophotometrically at a wavelength of at λ max =515 nm for Zn+2 complex . The conditions for complex formation and extraction Using (CPE)technique were studied and optimized , and the optimum pH is found =9 , critical volume the Triton X-100 concentration is at 0.5 mL, heating time is 85 C˚. Thermodynamic study of parameters to CPE are also calculated ,and their values Were as follows ΔH =0. 243874 KJ ,ΔG=-0. 181914134 KJ and ΔS =50.8821 J Indicating that the reaction is endothermic (LOD=6.4486x10-6µg mL-1) and LOQ= 6.4486x10-5µg mL-1 , with( Molar absorptivity Ɛ=286.88L.mol-1,cm-1. The Stoichiometry of the ]Zn+2(BTAD)[ showed that the ratio of M:L obtained are (1:1). at optimum conditions , the analysis 10 mL of sample yielded pre concentration Factor and enrichment factor of (200 and65.92366) respectively, while the Sandal's sensitivity(4.1x10-6 µg cm-2).Standard calibration curve was linearity at Range between 0.05-1ppm, with a correlation coefficient of 0.9933. The RSD% of Repeated measurements by a concentration of determinations at (90) µg 10mL−1 is 74.11%this developed method was applied to estimate Zinc concentration in Different samples and compered whit FAAS for samples and use t-test to compered The results accept Nell hypothesis and this method can be depend at confidence Limit 95%.

To determination of sulfanilamide (SNA) as a pure and pharmaceutical forms by easy, fast, and sensitive method. A liquid ion association complex of SNA formation by NiCl4-2 in the presence of nonionic surfactants TritonX-114 and mixture of (TritonX-114+Tween80) to form cloud point layer. The highest absorption at 277nm with both surfactants. The optimum conditions effect on the separation method was studied: concentration of HCl (0.8M), temperature (75℃), heating time (15min), the concentration of Ni (II) was 100μg.mL-1, and (0.5mL) of both surfactants. The calibration curve was linear over the concentration range of 10-100μg.mL-1with LOD of (0.984 μg.mL-1) and LOQ of (2.98 μg.mL-1) with TritonX-114 and LOD of (0.9936μg.mL-1) and LOQ of (3.011μg.mL-1) with mixture (TritonX-114+Tween80). SNA spectrophotometric determination was carried out by CPE and compared with HPLC. The results showed no significant differences between the two methods.

A new organic reagent [3-((2-chloro-4-hydroxyphenyl) diazenyl)-5nitrobenzene-1,2-diol] (CHPDND) was prepared and characterized by (IR, HNMR, 13C-NMR, C.H.N) used for spectrophotometric determination of Pb(II) ions in aqueous solution. The maximum wavelength of organic reagent λmax=410nm and for its complex with Pb(II) was 395nm. The study includes all optimal parameters for Pb(II) ions extraction as chelation complex by cloud point method such as pHex, temperature in addition to calculate thermodynamic data ΔHex, ΔGex, and ΔSex, heating time, surfactant volume, etc. Slope analysis method used for determine the probable structure of Pb(II)- (CHPDND) complex was 1:1. Applied method for spectrophotometric determination of Pb(II) in some environmental samples with LOD=0.219mg/L and LOQ=0.664mg/L and the results compared with AAS as standard method.

This review offers an in-depth exploration of the bioactivities, extraction techniques, formulation approaches and practical uses of naturally derived antioxidants in anti-ageing skincare. A critical analysis of the literature was performed. Extracts from leaves, aerial parts, seeds, peels, fruits and barks exhibit potent antioxidant, anti-inflammatory, photoprotective and anti-tyrosinase activities. Natural-based antioxidants exhibit a wide range of bioactivities as neutralizing free radicals through mechanisms such as metal chelation and activation of cellular antioxidant pathways (e.g. Nrf2/ARE) and anti-inflammatory effects by modulating cytokines like TNF-α and IL-6 and promoting wound healing by stimulating collagen synthesis and bioactive compound production. Extracts from Mucuna species, Magnolia officinalis and Arbutus unedo, for instance, demonstrate anti-ageing efficacy by inhibiting enzymes such as collagenase, elastase and MMPs. Certain fruit and seed extracts provide photoprotection with high SPF values, while others-such as mushroom extracts and essential oils-display potent antimicrobial activity. Their bioactivity is often enhanced through fermentation processes, innovative delivery systems like liposomes, niosomes and polymeric micelles, which improve stability, bioavailability and topical effectiveness. Extraction methods for natural antioxidants-including aqueous, hydroalcoholic, ultrasound-assisted (UAE), fermentation-assisted and alternative solvent (NaDES) techniques-are crucial for recovering and stabilizing bioactive compounds. Emerging green technologies such as supercritical CO2 extraction (SC-CO2), subcritical water extraction (SWE), supramolecular solvents (SUPRAS) and cloud point extraction (CPE) offer sustainable and selective recovery of bioactives with reduced environmental impact. These bioactives address oxidative stress, UV damage and dermal ageing, offering multifunctional applications in cosmeceuticals, pharmaceuticals and nutraceuticals. However, challenges such as photostability, inconsistent bioavailability and regulatory hurdles persist. Future research focusing on synergistic formulations, clinical validation and microbiome-friendly antioxidants will drive their advancement in next-generation sustainable skincare.

A spectrophotometric method was developed for the determination of hesperidin (HSP) in pharmaceutical preparations and bulk powder, characterized by sensitivity, simplicity, and ecofriendliness. The method involves diazotization of p-chloroaniline (PCA), followed by coupling with HSP in an alkaline medium. The resulting azo product is extracted using the cloud point extraction (CPE) with Triton X-114, and the absorbance was measured at 437 nm. Two approaches were used, i.e., the batch spectrophotometric method and the CPE technique. The batch method showed a detection limit of 0.409 μg/mL, while the CPE method achieved a significantly lower detection limit of 0.023 µg/mL. The linearity ranges were 3–40 and 1–8.5 μg/mL of HSP for the batch and CPE methods. Both methods demonstrated high precision (RSD < 1.17%) and excellent recovery rates, 99.18 to 102.27% for the batch method and 97.32 to 104.28% for CPE, with an enrichment factor of 4.7 using CPE. The methods were successfully applied to the analysis of HSP in supplement formulations and spiked urine samples without significant interference. A greenness evaluation using AGREE software confirmed its environmentally friendly nature. The proposed method offers a reliable, green, low-cost analytical approach suitable for routine pharmaceutical quality control in laboratories to analyze HSP in dosage forms.

Mixed micelles assisted room-temperature cloud point extraction for preconcentration and spectrophotometric determination of Molybdenum(VI).

ABSTRACT This study compared two different single-step extraction methods (IPS-CPE and UA-d-MSPE) using environmental assessment tools (BAGI, MoGAPI, SPMS, AGREE and CACI) for the efficient determination and preconcentration of Methyl Violet dye. The first method, the IPS-CPE method, used the formation of ion pair (Methyl Violet-SDS) between the cationic dye and anionic Sodium Dodecyl Sulfate (SDS). This ion pair is less soluble in water and can aggregate using Triton X-114 as a non-ionic surfactant into a highly solidified, viscous, and allowing for facile separation by decantation. The second method, UA-d-MSPE method utilises a reusable porous MWCNT/Fe3O4 nanocomposite adsorbent. The MWCNT/Fe3O4 was characterised XRD, EDX and FESEM, both before and after adsorption of Methyl Violet dye. The UA-d-MSPE method worked under reasonable conditions (35°C and 15 min in an ultrasonic bath) and utilises ethanol as the only eluent, with external magnetic field for separation and adsorbent recovery. A UV-Visible spectrophotometric method was validated for Methyl Violet quantification, covering ranges of 0.1–1 mg.L−1 for IPS-CPE and 0.2–2 mg.L−1 for UA-d-MSPE. Both methods exhibited excellent linearity (R2 = 0.999), high accuracy (99.925 ± 3.469% for IPS-CPE and 99.661 ± 2.956% for UA-d-MSPE) and low RSDs (3.471% for IPS-CPE and 2.966% for UA-d-MSPE). For IPS-CPE, the LOD and LOQ were 0.034 mg.L−1 and 0.097 mg.L−1, respectively. For UA-d-MSPE, the LOD and LOQ were 0.042 mg.L−1 and 0.176 mg.L−1. Both methods showed a good sensitivity, with preconcentration factors (PF) of 20 and enhancement factors (EF) of 15.36 for IPS-CPE, and PF of 40 and EF of 10.56 for UA-d-MSPE. This work presents a comparative assessment of two single-step extraction mechanisms using environmental assessments metrics. The application of higher scores from BAGI, MoGAPI, SPMS, AGREE, and CACI tools confirmed that UA-d-MSPE can be considered a greener chemistry method than IPS-CPE. This is due to UA-d-MSPE’s advantages, such as its simple process, reduced solvent consumption (only ethanol), recyclability of the porous MWCNT/Fe3O4 extractant, lower energy and time requirements, and minimal environmental effect.

Unraveling micro/nanoplastics and phthalates in infusion solutions: A novel integrated approach for quantification and cardiovascular cytotoxicity evaluation.

Copper contamination in industrial wastewater presents serious environmental concerns due to its toxicity and bioaccumulation. Conventional extraction methods often rely on hazardous organic solvents and lack specificity. This study introduces a green and selective system based on dithizone-functionalized deep eutectic solvents for copper ion extraction from aqueous media. The solvents were synthesized using L-isoleucine, aspartic acid, oleic acid, and ethyl methyl ketone, with dithizone incorporated as a metal-chelating ligand. Key operational parameters—including pH, solvent volume, Triton X-100 amount, Sudan II volume, copper concentration, temperature, and heating time—were systematically optimized. Spectrophotometric analysis at 550ௗnm was used to evaluate copper content, and both the distribution coefficient (log D) and extraction efficiency were determined. The optimized system (pH 8, 3.0ௗmL of solvent, 0.6ௗmL Triton X-100, 0.7ௗmL Sudan II, 65ௗ°C, 10 minutes heating) achieved a distribution coefficient of 1.955 and an extraction efficiency of 98.90%. Performance declined under non-optimal conditions due to reduced solubility or complexation efficiency. The method demonstrated strong selectivity and consistent performance across a wide copper concentration range. These results highlight the potential of dithizone-functionalized deep eutectic solvents as an effective, sustainable alternative for trace metal extraction in analytical and environmental applications

Sustainable disposable chitosan dip-coated paper-based sorbent for extraction of sunset yellow from food samples and pharmaceuticals.

Resource utilization of arsenic into As(0) by iodide/sulfite boosted photo-reduction and cloud point extraction

Cloud Point Extraction of Platinum Group Metal solutions: Key factors in metal extraction and selective elution at low concentrations

ABSTRACT Cloud point extraction is an eco-friendly technique used to extract phytochemical compounds via liquid-liquid extraction. Allium semenovii Regel is a medicinally important spice with potential source of polyphenols and antioxidants. The current study was proposed to develop more efficient method for separation and extraction of polyphenols and other compounds from aerial parts of A. semenovii. Thus, Cloud point extraction was used in comparison to aqueous extraction. CPE showed higher content of total polyphenols (44.47 ± 0.81 mg GAE/g) and flavonoid (54.28 ± 0.40 mg QE/g) than the aqueous extract. Furthermore, UPLC-PDA-based targeted polyphenol analysis showed highest amount of polyphenols including protocatechuic acid (2677.27 ± 0.05 µg/g), vanillic acid, and luteolin in CPE followed by CPEW and aqueous extract. GC-MS analysis of derivatized samples showed the presence of rare and important sugars. Samples also exhibited significant antioxidant activity, which might be due to the presence of hydroxyl group of compounds/polyphenols. Additionally, CPE showed the highest tyrosinase inhibitory activity using L-DOPA as substrate (IC50 = 0.42 ± 0.02 mg/mL) and α-glucosidase enzyme inhibition (IC50 = 0.07 ± 0.01 mg/mL). Hence, CPE was observed as safe, cost-effective, and environmentally friendly way to extract bioactive metabolites, including polyphenols from the vegetative matrix of A. semenovii.

A novel centrifuge-less cloud point extraction (CL-CPE) method was developed for the spectrophotometric determination of copper(II) using 4-nitrocatechol (4NC) as the chelating agent. The extraction system utilizes a mixed micellar phase composed of the nonionic surfactant Triton X-114 and the ionic liquid (IL) Aliquat® 336 (A336). The extracted ternary ion-association complex, identified as (A336+)2[Cu(4NC)2], exhibits a maximum absorbance at 451 nm, with a molar absorption coefficient of 8.9 × 104 M−1 cm−1 and a Sandell’s sensitivity of 0.71 ng cm−2. The method demonstrates a linear response in the copper(II) concentration range of 32–763 ng mL−1 and a limit of detection of 9.7 ng mL−1. The logarithmic extraction constant (log Kex) was determined to be 7.9, indicating efficient extraction. Method performance, evaluated by the Blue Applicability Grade Index (BAGI) and the Click Analytical Chemistry Index (CACI), confirmed its feasibility, practicality, simplicity, convenience, cost-effectiveness, environmental friendliness, and analytical competitiveness. The proposed IL-CL-CPE method was successfully applied to the analysis of a dietary supplement, a solution for infusion, and synthetic mixtures simulating various copper alloys.

The toxicity of metal ions, such as lead (Pb2+) and cadmium (Cd2+), has been a worldwide issue since the 1970s. For Pb2+ specifically, chronic exposure via drinking water can have lasting health effects. While inductively coupled plasma‐mass spectrometry (ICP‐MS) and atomic absorption spectroscopy (AAS) are the most common instruments used for the detection of Pb2+, electrochemical methods like square wave anodic stripping voltammetry (SWASV) have classically shown promise. However, the determination of metals in a real sample matrix typically requires pretreatment and/or extraction of the analyte from the sample itself. Cloud point extraction (CPE) is a sustainable technique that can be used as a solventless substitute for liquid–liquid or solid‐phase extraction. While typically coupled to AAS detection, the applicability of CPE to electroanalysis is still not well understood, nor fully optimized. In this work, CPE was used to isolate Pb2+ from water samples for analysis by SWASV with a bismuth‐coated glassy carbon (Bi‐GC) electrode. This is the first report coupling CPE to electroanalytical detection of trace metals in the absence of mercury (Hg). In addition, a back extraction (BE) step was incorporated to recover Pb2+ from the surfactant‐rich phase, which resulted in a more sensitive and accurate method. High extraction efficiency was achieved and theoretical limits of detection (LOD) of 2.6, 0.81, and 1.7 μgL−1 were obtained with deposition times (tdep) of 1, 2, and 3 min, respectively. The optimized CPE‐SWASV procedure for Pb2+ was selective; only manganese (Mn2+) was identified as an interferant. Measurements in more complex water samples were also completed. Overall, this innovative CPE‐SWASV approach offers a sensitive, cost‐effective, and sustainable alternative to Hg‐based electrochemical quantification of Pb2+.

Determination of the migration of six bisphenols from cans and sport bottles using rapid synergistic cloud point extraction and high-performance liquid chromatography

Citrus peel, a significant by-product of fruit processing, represents a rich source of carotenoids with strong antioxidant and health-promoting properties. The present study evaluated two green extraction techniques, cloud point extraction (CPE) and supramolecular solvent (SUPRAS)-based extraction, for carotenoids recovered from citron, orange, and tangerine peels. Whereas SUPRAS methods rely on a supramolecular solvent made of water, ethanol, and octanoic acid, CPE methods use surfactants and water, and both show a high potential to extract lipophilic components. CPE demonstrated superior efficiency in extracting total carotenoids and enhancing antioxidant activity, with orange peel extracts showing the highest concentrations. CPE and SUPRAS extracts were subsequently encapsulated using freeze-drying with chickpea protein isolate, achieving high encapsulation efficiencies (82.40–88.97%). The use of encapsulation technology is an effective strategy to protect carotenoids from environmental stressors. Color, morphological, and FTIR analyses confirmed the successful encapsulation and retention of carotenoids. Environmental impact was assessed using the EcoScale tool, revealing excellent sustainability for CPE (92 points) and satisfactory performance for SUPRAS-based extraction (70 points). The use of Generally Recognized As Safe (GRAS) solvents and plant-derived encapsulation materials makes this method highly suitable for clean-label product development across the food, cosmetic, and nutraceutical industries. In summary, the results point to a practical and sustainable approach to citrus waste valorization into valuable, health-promoting ingredients—supporting both circular economy goals and eco-friendly innovation.

A novel, environmentally friendly cloud point extraction (CPE) method based on 4-nitrocatechol (H2L) was developed in this study to spectrophotometrically determine trace vanadium. This method utilizes a mixed micelle-mediated system comprising a cationic surfactant (cetylpyridinium chloride, CPC) and a nonionic surfactant (Triton X-114). In contrast to conventional CPE, the present approach does not employ centrifugation to separate the two phases. The distinguishing characteristic of the extracted species, (CP+)[VVOL2], is its ability to absorb light across the entire visible spectrum. The measurement at 670 nm, where the complex displays a local maximum, is advantageous for two primary reasons. Firstly, the blank exhibits virtually no absorption, a property that engenders stable and reproducible results. Secondly, selectivity is high because almost all other metal complexes have absorption bands at shorter wavelengths. The proposed method has the following characteristics: a linear range of 2-305 ng mL-1, a limit of detection of 0.6 ng mL-1, a molar absorptivity coefficient of 1.22 × 105 M-1 cm-1, a Sandell sensitivity of 0.42 ng cm-2, and a blue applicability grade index (BAGI) of 67.5. Its efficacy was demonstrated in the analysis of mineral water, a spent vanadium-containing catalyst, and a dietary supplement.

A highly sensitive approach for separating and determining the micro amount of nickel (II) was conducted. It has been achieved after the formation of chelation complexes with 4-((4-hydroxyquinolin-3-yl) diazenyl) benzenesulfonamide (HQDBS) and 3-((1H-indol-5-yl)diazenyl)quinolin-4-ol (IDQ) as complexing agents (which are examined by using UV-Vis., FT-IR, and 1HNMR spectrum), including joint cloud point extraction with liquid ion exchange methods in the presence of the nonionic surfactant Triton X–100. The study is based on the wavelength values of maximum absorbance, λ max = 480 and 484 nm, respectively. The study optimized the extraction conditions, including the reagent concentration, temperature, heating duration, and surfactant volume. The concentration of reagents for achieving higher extraction efficiency is 1×10-3 M in the presence of 100 µg Ni (II)/mL of aqueous solution. The solutions should be heated at 80°C and 90°C HQDBS and IDQ respectively, for 15 minutes. The optimal volume of surfactants is 0.8 mL of Triton X-100 with HQDBS and 0.5 mL with IDQ. The study also includes an analysis of the impact of electrolytes and interferences and the spectrophotometric identification of Ni (II) in various samples.