Cloud Point Extraction Research Articles

Cloud point method applied to the extraction and preconcentration of thiabendazole pesticide from whole grape juice samples and amperometric detection by HPLC.

A cloud point method was developed and applied for the first time to extract and preconcentrate thiabendazole (TBZ) from commercial whole grape juice samples, with determination by high performance liquid chromatography coupled to electrochemical detection (HPLC/EC), using a cathodically pretreated boron-doped diamond electrode (BDD). The best conditions for extraction and preconcentration of TBZ by cloud point extraction (CPE) were performed at pH 6.0, by adding 1 mL of the surfactant Tergitol TMN-6 at 10% (mass-to-mass ratio), without heating (at 27 °C) and ultrasonic stirring time of (20 kHz) for 60 min. The HPLC/EC determination was duly validated in a C8 column, in mobile phase with a 69 : 31 ratio (V/V) of phosphate buffer (pH 7.0):ACN, at a flow rate of 1.2 mL min-1 and electrochemical detection with BDD electrode by applying 1.40 V × Ag/AgCl (3.0 mol L-1). Under these conditions, the procedure showed a preconcentration factor (FC) of 21.7, and limits of detection (LOD) and quantification (LOQ) of 6.64 × 10-9 mol L-1 (or 1.33 μg L-1) and 1.66 × 10-8 mol L-1 (or 3.34 μg L-1), respectively. The method provided a percent recovery of 81% to 98%, with a coefficient of variation between 3% and 15%.

Aspirin Spectrophotometric Determination using Cloud Point Extraction and HPLC in Several Pharmaceuticals Sold in Iraqi Markets

In this work, a sensitive tandem cloud-point extraction (CPE) method with a solvation system was employed to detect aspirin in various pharmaceuticals. Aspirin, in a dilute acidic solution, formed a complex with Zn(II) ions ([Zn(II)-aspirin] complex), which was then extracted using two different surfactant systems - nonionic surfactant Triton X-100 and a mixture of surfactants (SDS-Tween 80). The extracted complex was subsequently determined using spectrophotometry at a wavelength of 293 nm for Triton X-100 and 231 nm for SDS-Tween 80. The parameters for extraction, including HCl and Zn(II) concentration, temperature, heating time, and solvent used to dissolve the cloud point layer, were thoroughly investigated. Highperformance liquid chromatography (HPLC) was used as the standard method to compare the quantitative analysis of the cloud-point extraction-onium system.

Visual detection of microplastics using Raman spectroscopic imaging.

As a new type of pollutant in the marine environment and terrestrial ecosystems, microplastics have attracted widespread attention. Assessing the ecological risk of microplastics relies on accurately detecting small-sized particles in the environment. Microplastics exhibit unique "fingerprint" characteristics in Raman spectroscopy, making them suitable for rapid identification. In this study, we achieved visualization of microplastics through pseudo-color images generated by Raman spectroscopy imaging. Pseudo-color imaging maps were generated by selecting characteristic peaks and the classical least-squares fitting method was used to visually represent the distribution of different microplastics. The study explored the potential of Raman spectroscopy and its mapping mode in distinguishing various types of mixed microplastics and demonstrated that this approach can identify microplastics in complex environmental samples. Specifically, a cloud-point extraction followed by membrane filtration method was successfully applied to identifying mixed-component microplastics. In summary, the category, quantity, location, and differentiation of microplastics can be accurately analyzed by Raman spectroscopy, which provides a basis for assessing their ecological risk.

Kinetics, thermodynamics and isotherm modelling of cloud point extraction of lycopene

Kinetics, thermodynamics and isotherm modelling of cloud point extraction of lycopene

Simultaneous Preconcentration and Determination of Nile Blue A and Rhodamine B in Aqueous Samples by the Cloud Point Extraction Coupled with the Solution Scanometric Method

Simultaneous Preconcentration and Determination of Nile Blue A and Rhodamine B in Aqueous Samples by the Cloud Point Extraction Coupled with the Solution Scanometric Method

A novel in-syringe cloud point extraction method for the determination of cadmium and lead in human hair samples

Measurement of contaminant elements in biological samples requires time-consuming sample preparation. The proposed in-syringe cloud point extraction (IS-CPE) as a fast, easy, low-cost, and green method was successfully used to measure lead and cadmium in human hair samples.

Cloud Point Extraction Method for Separation and Preconcentration of Molybdenum and Zirconium Using Mixture of Surfactants from Natural Waters and their Determination by Spectrophotometry

Cloud Point Extraction Method for Separation and Preconcentration of Molybdenum and Zirconium Using Mixture of Surfactants from Natural Waters and their Determination by Spectrophotometry

Green Cloud Point Extraction Coupled for Separation and Determination of Erythrosine in Various Samples Compared to the HPLC Technique

Green Cloud Point Extraction Coupled for Separation and Determination of Erythrosine in Various Samples Compared to the HPLC Technique

Застосування міцелярної екстракції для визначення арсену методом атомно-емісійної спектрометрії з індуктивно-зв'язаною плазмою у низці фармацевтичних препаратів

Application of cloud-point extraction for arsenic determination in pharmaceuticals of various types: Calcium gluconate, solution for injection 100 mg mL-1, Potassium chloride, solution for injection 4 %, and Magnesium sulfate, solution for injection 25 %, was investigated. It has been demonstrated that direct quantitative extraction of arsenic into the micellar phase of Triton X-100 in the form of molybdoarsenic acid is possible only for potassium chloride. Magnesium sulfate requires at least five times dilution for arsenic to quantitatively enter the micellar phase. In the case of calcium gluconate, the organic anion is likely to have a higher affinity for the Triton X-100 phase than molybdoarsenic acid resulting in very low extraction coefficient values. In this case, decomposition of the drug was suggested. Three decomposition methods were evaluated and compared: acid decomposition in an open system, acid decomposition in a microwave reactor, and ashing with MgO/Mg(NO3)2. The second and third methods provide further quantitative removal of arsenic, the second being more rapid and easier to perform.

Simultaneously HPLC Analysis of B1, B9 and B12 Vitamins at Trace Levels via Cloud Point Extraction

An enrichment and determination method based on liquid chromatographically analysis and cloud point extraction (CPE) has been developed for trace levels of B vitamins (B1, B9 and B12) in the proposed study. Vitamin molecules were drawn into the non-ionic surfactant phase of Polyethylene Glycol (PEG-6000) in the presence of pH 9.0 medium. The surfactant-rich phase separated by centrifugation and then dissolved with 700 µL of ethanol. The obtained ethanol phase was filtered by 0.45-micron filter prior to the HPLC analysis. All parameters affecting the CPE method such as pH, buffer volume, incubation time, surfactant and electrolyte concentration, solvent for the surfactant-rich phase and its amount have been individually studied and optimized step by step. After the optimization of all parameters of the CPE process, the detection limits of the developed method for B1, B9 and B12 vitamins were calculated as 1.42 ng mL-1, 7.14 ng mL-1 and 14.28 ng mL-1 , respectively. The linear working ranges for three vitamin molecules was obtained in the range of 5.0-500.0 ng mL-1. After CPE procedure, determination of vitamin molecules was carried out by using HPLC system with diode array detector(DAD) at 244 nm for vitamin B1, 285 nm for vitamin B9, and 361 nm for vitamin B12, respectively

Investigation of the Polyphenol Recovery of Overripe Banana Peel Extract Utilizing Cloud Point Extraction

Consuming fruits and vegetables necessitates discarding the inedible parts, which raises issues such as waste management and contamination of the environment. Numerous studies have been conducted in recent years in an effort to identify alternatives that reduce the negative effects of food and agricultural waste. This study aims to investigate the polyphenol recovery and the antioxidant capacity of overripe banana peel through cloud point extraction (CPE), which is a green method. The optimal conditions of the CPE were three steps of CPE with 10% w/v lecithin, which was used as surfactant, pH 7, and a salt concentration of 15% at 45 °C for 20 min. The total polyphenol content (TPC) was determined to be 541.25 mg GAE/L, the total flavonoid content (TFC) was determined to be 226.38 mg RtE/L, and FRAP and DPPH assays were found to be 2.52 and 2.91 mmol AAE/L, respectively. According to the results, the antioxidant compounds from banana peels can effectively be extracted with the proposed CPE procedure. The as-prepared extracts can potentially be used as food additives to improve human well-being and even as feed additives for a similar purpose.

New spectrophotometric determination sulfamethaxazole drug via various analytical techniques in pharmaceutical formulation

The first method on the oxidative coupling Amoxixilin reaction with 2,4- dinitrophenyl hydrazine and Sodium Iodate diluted to produce a soluble red-Orange dye product was devised to estimate the Amoxicillin in bulk and pharmaceutical preparation. The concentration range is between 1 and 50 g/mL. Beer's law is met by the product in terms. With a molar absorptivity of 6.2×103L.mol-1.cm-1 and a correlation coefficient of 0.9995, Sandell's sensitivity is 0.059g.cm-2 at 475 nm. A second technique for determining a trace amount in an aqueous solution product is called cloud point extraction (CPE), and it is based on measurements made with a UV-visible spectrophotometer at a wavelength of 480 nm. The correlation coefficient was 0.9996 and the Beer's law concentration range was 0.25–6 g/mL The molar absorptivity was 103623.79 L.mol-1.cm-1. Pre-concentration 25, detection of limit 0.023 µg/mL. The distribution coefficient (D) was 158.6, and enrichment factor was 28.35. The last method is flow injection analysis, which is straightforward to estimate. The Beer's law concentration range was 2-150 µg / mL, Sandell's sensitivity is 0.13 µg.cm-2 at 475 nm, with a molar absorptivity of 2.8×103 L.mol-1.cm-1 and correlation coefficient was 0.9996, it is successfully used for drug estimation. Qualities in a straightforward situation or pharmacological formulations.
 
 
 

Compatibility of cloud point extraction with gas chromatography: Matrix effects of Triton X-100 on GC-MS and GC-MS/MS analysis of organochlorine and organophosphorus pesticides

Cloud point extraction is an environmentally benign and simple separation/concentration procedure that can be regarded as an alternative to classical liquid-liquid extraction. In the current work, it was studied the compatibility of cloud point extraction followed by back-extraction in low volume of organic solvent with gas chromatography-mass spectrometry (GC-MS and GC-MS/MS). Triton X-100 was preferred than Triton X-114 as a surfactant to produce the clouding phenomenon and hexane or isooctane was found to be appropriate organic solvents which can be used at the back-extraction step. It was observed that ca. 0.09 % w/w Triton X-100 was co-extracted in the organic phase (hexane or isooctane) so further study was carried out to find out its effect on the GC-MS (GC-MS/MS) measurement when liquid samples are injected without any pre-cleaning to remove the surfactant. The chromatographic separation and the mass detection were not deteriorated by the concomitant Triton X-100 for analysis of several Organochlorine and Organophosphorus pesticides (alpha-HCH, beta-HCH, gamma-HCH, Pentachlorobenzene, Hexachlorobenzene, Chlorpyrifos, Chlorpyrifos-methyl, Aldrin, Endrin, Dieldrin, alpha-Endosulfan, Heptachlor, Heptachlor-endo-epoxide-A, o,p-DDD, p,p-DDD, o,p-DDE, p,p-DDE, o,p-DDT and p,p-DDT). The stability of the GC system when introducing surfactant was assessed as acceptable (typically the peak area RSD% for 20 consecutive injections were below 5 %). Under the developed vaporization conditions using PTV or PSS injectors it can be deduced that Triton X-100 is deposited on the inner surface of the liner. This effect is beneficial since the resulting surfactant layer makes a surface which facilitates the pesticides transfer to the GC column. As a consequence, for some analytes, a substantial enhancement (up to 2.3 times) in the sensitivity was observed when the matrix-matched medium (0.09 % w/w Triton X-100 in organic solvent) is used compared to calibration in solely hexane or isooctane. Meanwhile, the measurement precision in the presence of Triton X-100 remains unchanged. The GC-MS/MS analysis was alternatively accomplished by the use of glass or metal liner and it was found that the glass one should be preferable. Finally, it can be concluded that cloud point extraction with Triton X-100 can be combined with GC-MS or GC-MS/MS analysis by applying liquid injection of the target analytes transferred in organic solvents such as hexane or isooctane. We have established a positive effect of Triton X-100 on the instrumental performance which is on opposite to the generally accepted concern of the negative influence of the surfactants on the gas chromatographic analysis.

Removal of Aluminum from Synthetic Rare Earth Leach Solution by Selective Complexation and Turbidity Point Extraction

During the leaching process of ion-adsorbed rare earth ores, large amounts of non-rare earth impurities such as aluminum and iron will be generated. This study selected glutamic acid as a complex agent to selectively calculate aluminum ions; then, added non-ionic surfactants and extract and separate aluminum ions from a rare earth solution using the cloud point extraction method. The effects of solution pH, reaction temperature, equilibration time, amount of glutamic acid, reaction time, and amount of Triton X-114 on aluminum extraction were investigated. The results showed that with a Mglu:MAl ratio of 3:1, a solution pH of 4.5, a constant temperature of 40 °C, and the addition of 10 mL Triton X-114 after 10 min of reaction time, the single extraction efficiency of aluminum ions reached 78.01%, and the extraction efficiency of rare earths was only 5.09% after 10 min of equilibration time. The reaction equation of glutamic acid with aluminum ions was determined, and the lowest extraction concentration of aluminum ions in the glutamic acid complexation extraction solution was found to be cAl = 0.045 ± 0.003 g/L, with a separation coefficient of β(Al/RE) = 66.15. This result indicated that the aluminum ions in the mixed solution could be effectively separated from the rare earth ions when using glutamic acid as a complexing agent in combination with the turbidity point extraction method.

Cloud point extraction coupled HPLC for a green downstream process and quantification of 1,9β,17,21-tetrahydoxy-4-methyl-19-nor-9β-pregna-1,3,5(10)-trien-11,20-dione and 1,9β,17,20β,21-pentahydoxy-4-methyl-19-nor-9β-pregna-1,3,5(10)-trien-11-one obtained by microbial biotransformation of cortisone

The widespread use of corticosteroids as molecules with high therapeutic potential has shown a gradual increase in recent years, but there is a need to progressively have molecules with high therapeutic effects but an increasingly low side effect profile. The chemical approach to the synthesis of new corticosteroids is often time-consuming, expensive, impacts the environment, difficult, and requires multiple manufacturing steps in contrast to new green approaches. In recent decades, microbial biotransformation has introduced an alternative to chemical synthesis of corticosteroids; however, although biotransformation seems to be a good alternative approach to traditional synthetic routes, the products often require difficult downstream purification processes. The purpose of this work was to identify an alternative process to liquid-liquid extraction for the isolation of two new steroids, 1,9β,17,21-tetrahydoxy-4-methyl-19-nor-9β-pregna-1,3,5(10)-trien-11,20-dione (SCA) and 1,9β,17,20β,21-pentahydoxy-4-methyl-19-nor-9β-pregna-1,3,5(10)-trien-11-one (SCB), obtained by biotransformation of cortisone with Rhodococus rhodnii. Cloud point extraction was chosen and applied for the first time as a “green” downstream method, as it is characterized by a profile of low cost, short extraction time, aqueous environment, moderate temperature, as well as performed with absolutely non-impactful and non-toxic extraction agents. Therefore, this study allowed the evaluation of the main factors affecting cloud point extraction, such as the concentration of polyethylene glycol tert-octylphenyl ether (TX-114), chosen as the extraction agent, of the electrolytes, such as NaCl, of the temperature and equilibration time at which the extraction is performed. Evaluation of extraction efficiencies was performed by RP-HPLC with values of 96% for SCA and 86% for SCB in real biotransformation samples. The analytical performances of the method were evaluated in terms of limits of detection (0.022 g L-1 for SCA and 0.016 g L-1 for SCB), limits of quantification (0.069 g L-1 for SCA and 0.050 g L-1 for SCB), linearity (0.072–3.82 g L−1). The relative standard deviations were calculated for the repeatability (0.54–0.91% for SCA and 0.70–3.80% for SCB) and stability (0.62–0.80% for SCA and 2.21–2.54% for SCB) of the proposed method. The accuracy was evaluated through recovery studies in relation to 50%, 100%, 150% excess analytes, allowing to obtain 99.69–99.77% recovery of SCA and 99.24–99.51% for SCB with RSD% less than 5%.

Antioxidant Capacity in Two Different Cultivars of Ripe and Unripe Peaches Utilizing the Cloud-Point Extraction Method

In this study, the objective was to ascertain the optimal extraction method for the recovery of polyphenols from two peach cultivars, namely ‘Andross’ and ‘Everts’, at unripe and ripe stages. Two extraction techniques were explored: conventional extraction and cloud-point extraction (CPE), utilizing various solvents, including water, ethanol, 60% ethanol, and the surfactant Tween 80. Moreover, the conditions of CPE (such as pH, ionic strength, surfactant concentration, etc.) were optimized. To elucidate the antioxidant activity of the extracts, the total polyphenol content (TPC), the ferric-reducing antioxidant power (FRAP) assay, and the DPPH antiradical scavenging were measured. Our findings indicate that CPE is a superior method for polyphenol recovery. Unripe fruits had more antioxidants than ripe ones. Unripe ‘Andross’ fruit has a TPC of 1465.32 mg gallic acid equivalents per kilogram (mg GAE/kg). FRAP and DPPH levels were 7.33 and 5.12 mmol ascorbic acid equivalents (AAE/kg), respectively. With a TPC of 1714.53 mg GAE/kg, the unripe fruit from the ‘Everts’ cultivar has even more antioxidant capacity. Additionally, its FRAP and DPPH values were increased at 8.57 and 6.08 mmol AAE/kg, respectively. These findings underscore the efficacy of CPE as a preferred method for polyphenol extraction while also highlighting the enhanced antioxidant potential of unripe peaches, particularly in the ‘Everts’ cultivar.

LOW TEMPERATURE ANALYTICAL CLOUD POINT EXTRACTION. 1: PROTOLYTIC PROPERTIES OF ACIDIC EXTRACTION INITIATORS IN ORGANIZED MEDIA

Cloud point extraction is a powerful tool for the analytical preconcentration of trace amounts of analytes. The standard cloud point extraction procedure requires prolonged heating of the solution, which is not always appropriate in the case of thermally unstable analytes or analytical forms and significantly limits the capabilities of the method. One of the ways to modify cloud point extraction is to find approaches to intensifying the process of analytical concentration. The main disadvantage of cloud point extraction is the need for thermal, ultrasonic, infrared or any other initiation of the formation of the surfactant-rich phase. The difficulty lies in the fact that such influence on the system is not always appropriate and possible, and can also negatively affect the formation of the target analytical form. The purpose of this work is to search for new initiators of cloud point extraction and justify the possibility of their analytical use. In the current paper, the ionization constants (pKa) of some cloud point extraction initiators such as aromatic carboxylic acids (benzoic, 4-chlorobenzoic, 3-nitrobenzoic, 2,4-dihydroxybenzoic, o-, m-, p-toluic and salicylic acids) in water and Triton X-100 micellar solutions at various concentrations of surfactant in the studied systems have been determined by the potentiometric titration method. It was found that the values of pKa of aromatic carboxylic acids (benzoic, 4-chlorobenzoic, 3-nitrobenzoic, 2,4-dihydroxybenzoic, o-, m-, p-toluic and salicylic acids) in water and Triton X‑100 micellar solutions naturally increase with increasing concentration of surfactant in the system. It is shown that the nature and the physico-chemical properties of the environment influence the nature and degree of change in the acid-base properties of the studied aromatic carboxylic acids (benzoic, 4-chlorobenzoic, 3-nitrobenzoic, 2,4-dihydroxybenzoic, o-, m-, p-toluic and salicylic acids). Criteria for the selection of cloud point extraction initiators are proposed, which allow analytical concentration to be carried out at room temperature.

Advancements in Preprocessing and Analysis of Nitrite and Nitrate since 2010 in Biological Samples: A Review.

As a substance present in organisms, nitrite is a metabolite of nitric oxide and can also be ingested. Nitrate is the metabolite of nitrite. Therefore, it is necessary to measure it quickly, easily and accurately to evaluate the health status of humans. Although there have been several reviews on analytical methods for non-biological samples, there have been no reviews focused on both sample preparation and analytical methods for biological samples. First, rapid and accurate nitrite measurement has significant effects on human health. Second, the detection of nitrite in biological samples is problematic due to its very low concentration and matrix interferences. Therefore, the pretreatment plus measuring methods for nitrite and nitrate obtained from biological samples since 2010 are summarized in the present review, and their prospects for the future are proposed. The treatment methods include liquid-liquid microextraction, various derivatization reactions, liquid-liquid extraction, protein precipitation, solid phase extraction, and cloud point extraction. Analytical methods include spectroscopic methods, paper-based analytical devices, ion chromatography, liquid chromatography, gas chromatography-mass spectrometry, electrochemical methods, liquid chromatography-mass spectrometry and capillary electrophoresis. Derivatization reagents with rapid quantitative reactions and advanced extraction methods with high enrichment efficiency are also included. Nitrate and nitrate should be determined at the same time by the same analytical method. In addition, much exploration has been performed on formulating fast testing through microfluidic technology. In this review, the newest developments in nitrite and nitrate processing are a focus in addition to novel techniques employed in such analyses.

Colorimetric and fluorescent dual mode detection of Fe (III) ion in blood samples in combination with cloud point extraction

Both cloud point extraction and spectrophotometry, as well as cloud point extraction and spectrofluorometry, were developed to achieve sensitive and selective identification and measurement of iron. The technique relies on forming a complex between ferric iron (Fe3+) and 5-amino salicylic acid (MSZ), also known as mesalazine reagent. This complex is then extracted into a Triton X-114-rich nonionic surfactant phase.At a wavelength of 550 nm, spectrophotometric analysis of the extracted complex is performed. The other method employs spectrofluorometric determination, which entails quenching the fluorescence intensity of the mesalazine reagent. The excitation wavelength for this determination is 338 nm,and the emission wavelength is 496 nm.These two methods have a dynamic linear range of 1 to 23 μg mL−1 for colorimetry with a detection limit and enrichment factor of 0.0121 μg mL−1 and 4.52, respectively, and 0.1 to 1.4 μg mL−1, with a detection limit of 0.0053 μg mL−1 for fluorimetry.Spiked samples (artificially enriched with iron) were used to evaluate the method's accuracy. The procedures were also deployed successfully to identify and quantify iron in biological samples, yielding positive results. In addition, the analytical results are statistically consistent with those derived from a stimulation procedure, further validating the method's reliability.

Exploring the Feasibility of Cloud-Point Extraction for Bioactive Compound Recovery from Food Byproducts: A Review

In recent years, the production of food biomass waste has been increasing rapidly. This necessitates urgent measures to be taken so as to utilize them. Since most food biomass waste contains useful bioactive substances, cloud-point extraction (CPE) has emerged as a promising solution to valorize waste. CPE is an extraction method employed for the extraction and preconcentration of various chemical compounds, including polyphenols and flavonoids. As with any other extraction procedure, CPE isolates the target compound(s) from the sample, resulting in increased recovery. One major advantage of CPE is that the extraction is carried out without special equipment or harmful reagents. Moreover, other significant advantages are its effectiveness, simplicity, safety, and rapidity. This review focuses on the extraction of bioactive compounds from food-based waste using CPE and highlights the important parameters that can be tuned to improve the performance of CPE. Furthermore, the potential in promoting environmentally friendly practices within the food industry is also discussed.