Optimization and modeling of preconcentration and determination of dyes based on ultrasound assisted-dispersive liquid-liquid microextraction coupled with derivative spectrophotometry

Study on oxidation behavior during process of recycling carbon fibers from CFRP by pyrolysis

The study utilized a pyrolysis method to recycle carbon fibers from carbon fiber reinforced polymer (CFRP), followed by oxidation to remove pyrolysis carbon. The obtained recycled carbon fibers had good mechanical properties, and the tensile strength could reach 96.2% of the virgin carbon fibers under the optimal process conditions. The recycled carbon fibers displayed similar chemical structure and graphitization degree as the virgin carbon fibers, and showed better wettability with epoxy resin. In addition, density functional theory (DFT) calculations were also employed to analyze the mechanism of pyrolysis carbon oxidation removal. The results showed that the adsorption energy of oxygen on pyrolytic carbon and the reaction activation energy were lower than those of carbon fibers, indicating that pyrolytic carbon was more easily oxidized than carbon fibers. This allowed pyrolytic carbon to be removed by oxidation at relatively low temperatures and preserved the integrity of carbon fibers, thus ensuring that the carbon fibers also maintained excellent mechanical properties after recycling. This study helps to reveal the oxidation mechanism of resin pyrolysis carbon, providing technical support for efficient and clean recycling of carbon fibers.

CaTiO3/g-C3N4 heterojunction-based composite photocatalyst: Part I: Experimental design, kinetics, and scavenging agents' effects in photocatalytic degradation of gemifloxacin

A critical, challenging environmental issue is explored pollution of water supplies by discharging industrial/pharmaceutical/hospital/urban wastewaters into the aquatic environment. These needs introducing/developing novel photocatalysts/adsorbents/procedures for removing or mineralizing various pollutants in wastewater before discharging them into marine environments. Further, optimizing conditions to achieve the highest removal efficiency is an important issue. In this study, CaTiO₃/g-C₃N₄ (CTCN) heterostructure was synthesized and characterized by some identification techniques. The simultaneous interaction effects of the experimental variables on the boosted photocatalytic activity of CTCN in the degradation of gemifloxcacin (GMF) were studied in RSM design. The optimal values for four parameters were: catalyst dosage: 0.63 g L^-1, pH: 6.7, C_GMF: 1 mg L^-1, and irradiation time: 27.5 min, with approximately 78.2% of degradation efficiency. The quenching effects of the scavenging agents were studied to show the reactive species' relative importance in GMF photodegradation. The results illustrate that the reactive ^•OH plays a significant role, and the electron plays a minor role in the degradation process. The direct Z-scheme mechanism better described the photodegradation mechanism due to the great oxidative and reductive abilities of prepared composite photocatalysts. This mechanism is an approach to efficiently separating photogenerated charge carriers and improving the CaTiO₃/g-C₃N₄ composite photocatalyst activity. The COD has been performed to study the details of the mineralization of GMF. The pseudo-first-order rat (from the Hinshelwood model) constants of 0.046 min^-1 (t_1/2 = 15.1 min) and 0.048 min^-1 (t_1/2 = 14.4 min) were respectively obtained from the GMF photodegradation data and COD results. The prepared photocatalyst retained its activity after five reusing runs.

The potential application of bio-based ceramic/organic xerogel derived from the plant sources: A new green adsorbent for removal of antibiotics from pharmaceutical wastewater

A bio-based ceramic/organic xerogel (BCO-xerogel) was obtained from the combination of sugarcane bagasse ash, polyvinyl alcohol, and pine cone-derived tannin extract, which are abundant, non-toxic, and renewable sources. The as-prepared BCO-xerogel was used as a low-cost green adsorbent for the eliminate of four types of the most widely used antibiotics, including amoxicillin (AMX), tetracycline (TC), cefalexin (CLX), and penicillin G (PEN G) residuals from contaminated water. The simultaneous effects conventional variables including adsorbent dosage, antibiotic concentrations, solution pH, and contact time were studied and optimized by central composite design (CCD) under response surface methodology (RSM). Analysis of variance (ANOVA) was employed as a statistical formula to determine the significance of operating environmental conditions and their interactions with 95% confidence limits. Under optimized conditions, the experimental removal efficiencies for AMX, TC, CLX, and PEN G were 98.78 ± 3.25, 99.12 ± 2.52, 98.02 ± 1.98, and 98.42 ± 2.19, respectively. The adsorption isotherms and kinetics were better fitted with Langmuir and pseudo-second-order models, respectively. Thermodynamic studies showed that the adsorption process was endothermic, spontaneous, and occurred by combination of physical and chemical mechanisms. Also, evaluating the ability of BCO-xerogel to adsorptive removal of AMX, TC, CLX, and PEN G antibiotics in real wastewaters showed about 97.4-98.6% adsorption efficiency in river water and about 67.1-71.3% in three hospital effluents. After the adsorption process, the antibiotic-loaded adsorbent was regenerated by NaOH (0.01 mol L^-1), and the reusability tests showed that the removal efficiencies of the antibiotics in the four recovery steps were still above 90%. This work explored the development of green, efficient, and economical bio-adsorbent that can be utilized for the removal of antibiotics from contaminated wastewaters.

Experimental modelling studies on the removal of dyes and heavy metal ions using ZnFe2O4 nanoparticles

The presence of dyes and heavy metals in water sources as pollutants is harmful to human and animal health. Therefore, this study aimed to evaluate the efficacy of zinc ferrite (ZnFe2O4) nanoparticles (ZF-NPs) due to their outstanding properties including cost-effectiveness, availability, and applicability for removal of auramine O (AO), methylene blue (MB), and Cd (II). The effect of the main operating parameters such as AO concentration, MB concentration, Cd (II) concentration, adsorbent amount, solution pH, and sonication time was optimized by the response surface methodology (RSM). Optimal conditions were obtained at adsorbent amount of 0.25 g, pH = 6, sonication time of 15 min, and concentration of 15 mg L-1, and more than 91.56% were removed from all three analytes. The adsorption of AO, MB, and Cd (II) onto ZF-NPs followed pseudo-second-order kinetics and the equilibrium data fitted well with Langmuir isotherm. The maximum adsorption capacities of ZF-NPs for AO, MB and Cd (II) were as high as 201.29 mg g-1, 256.76 mg g-1 and 152.48 mg g-1, respectively. Also, the reuse of the adsorbent was investigated, and it was found that the adsorbent can be used for up to five cycles. Based on the results of interference studies, it was found that different ions do not have a significant effect on the removal of AO, MB, and Cd (II) in optimal conditions. The ZF-NPs was investigated successfully to remove AO, MB, and Cd (II) from environmental water samples. The results of this study showed that ZF-NPs can be used as a suitable adsorbent to remove AO, MB, and Cd (II) from aqueous solution.

Quantification of twenty pharmacologically active dyes in water samples using UPLC-MS/MS

This study presents a multi-compound method for the determination of 20 pharmacologically active dyes from 5 different chemical classes in environmental water samples. These compounds, including triphenylmethane dyes (malachite green, crystal violet, brilliant green, ethyl violet, methyl violet 2B, pararosaniline, victoria blue B, victoria blue R, victoria pure blue BO), phenothiazine dyes (methylene blue, azure A, azure B, azure C, new methylene blue, thionine), phenoxazine dye (nile blue A), acridine dyes (acriflavine, proflavine) and xanthene dyes (rhodamine B, rhodamine 6G) constitute pharmacologically active substances (PASs). For the optimisation of sample preparation, different solid-phase extraction (SPE) sorbents and a wide range of pH (from 2 to 12) of water samples were tested. Finally, water samples were preconcentrated and cleaned up on diol SPE cartridges. Extracts were analysed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) operating in the positive electrospray ionisation (ESI+) mode. The chromatographic separation of the 20 pharmacologically active dyes was achieved within 5 min by using a pentafluorophenyl (F5) analytical column and mobile phases of ammonium acetate buffer (0.05 M, pH = 3.5) and acetonitrile with gradient elution. The developed method was validated proving to be suitable for the determination of all tested compounds. Limits of quantification were 0.01–0.1 μg/l, are sensitive enough to quantify very low concentration levels of the dyes in environmental water samples. The obtained recovery values for all tested analytes were between 71.2 and 104.9% with a good RSD, less than 14 % at all fortification levels. The application of the developed method to water samples allows the detection of dyes such as crystal violet, rhodamine B, and methyl violet in two wastewater samples in concentration range from 0.017 to 0.0043 μg/l).

NH2NH-MOF: a reaction matrix for the specific determination of small aldehydes by MALDI-MS

Efficient determination of aldehydes by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is hampered mainly by the low mass and unstable nature of analytes. In the present work, we propose a combined strategy of a reactive metal-organic framework (MOF) matrix for the derivatization and detection of aldehydes. A novel reactive MOF matrix (NH₂NH-MOF) was synthesized in two steps. First, NR₃⁺-MOF was synthesized via Cu²⁺ and the quaternary amine ligand 4,4'-bipyridinium, 1,1″-(1,2-ethanediyl)bis-, dibromide (PyEtBr). Then, -NHNH₂ was introduced to NR₃⁺-MOF through electrostatic adsorption between the -NR₃⁺ and -HSO₃^- of 4-hydrazinylbenzenesulfonic acid to synthesize NH₂NH-MOF. The acid-base chemistry of NH₂NH-MOF led to uniform cocrystallization of the aldehyde-matrix mixtures and helped to achieve the detection of low-weight aldehydes with good relative standard deviations (RSDs = 0.07-12.35%). It was confirmed that this strategy can accurately quantify formaldehyde, valeraldehyde, and benzaldehyde with good linearity (r > 0.97). Furthermore, this strategy was applied to quantitatively detect benzaldehyde in wastewater, thus showing potential applications in environmental pollutant detection.

Application of ultrasound in combination with other technologies in food processing: A review

The use of non-thermal processing technologies has been on the surge due to ever increasing demand for highest quality convenient foods containing the natural taste & flavor and being free of chemical additives and preservatives. Among the various non-thermal processing methods, ultrasound technology has proven to be very valuable. Ultrasound processing, being used alone or in combination with other processing methods, yields significant positive results on the quality of foods, thus has been considered efficacious. Food processes performed under the action of ultrasound are believed to be affected in part by cavitation phenomenon and mass transfer enhancement. It is considered to be an emerging and promising technology and has been applied efficiently in food processing industry for several processes such as freezing, filtration, drying, separation, emulsion, sterilization, and extraction. Various researches have opined that ultrasound leads to an increase in the performance of the process and improves the quality factors of the food. The present paper will discuss the mechanical, chemical and biochemical effects produced by the propagation of high intensity ultrasonic waves through the medium. This review outlines the current knowledge about application of ultrasound in food technology including processing, preservation and extraction. In addition, the several advantages of ultrasound processing, which when combined with other different technologies (such as microwave, supercritical CO2, high pressure processing, enzymatic extraction, etc.) are being examined. These include an array of effects such as effective mixing, retention of food characteristics, faster energy and mass transfer, reduced thermal and concentration gradients, effective extraction, increased production, and efficient alternative to conventional techniques. Furthermore, the paper presents the necessary theoretical background and details of the technology, technique, and safety precautions about ultrasound.

Optimization of Flow Rate and Pipe Rotation Speed Considering Effective Cuttings Transport Using Data-Driven Models

Effectively transporting drilled cuttings to the surface is a vital part of the well construction process. Usually, mechanistic models are used to estimate the cuttings concentration during drilling. Based on the results from these model, operational parameters are adjusted to mitigate any nonproductive time events such as pack-off or lost circulation. However, these models do not capture the underlying complex physics completely and frequently require updating the input parameters, which is usually performed manually. To address this, in this study, a data-driven modeling approach is taken and evaluated together with widely used mechanistic models. Artificial neural networks are selected after several trials. The experimental data collected at The University of Tulsa–Drilling Research Projects (in the last 40 years) are used to train and validate the model, which includes a wide range of wellbore and pipe sizes, inclinations, rate-of-penetration values, pipe rotation speeds, flow rates, and fluid and cuttings properties. It is observed that, in many cases, the data-driven model significantly outperforms the mechanistic models, which provides a very promising direction for real-time drilling optimization and automation. After the neural network is proven to work effectively, an optimization attempt to estimate flow rate and pipe rotation speed is introduced using a genetic algorithm. The decision is made considering minimizing the required total energy for this process. This approach may be used as a design tool to identify the required flow rate and pipe rotation speed to acquire effective hole cleaning while consuming minimal energy.

Ultrasonic-assisted cloud point microextraction and spectrophotometric determination of Ponceau 4R in various beverage samples using Non-ionic surfactant PONPE 7.5

In the current study, a simple, cheap, and fast analytical procedure, termed ultrasonic-assisted cloud point microextraction (UA-CPME), combined with UV-VIS spectrophotometry, was developed for the pre-concentration and identification of Ponceau 4R in some beverage samples. Ponceau 4R was extracted from aqueous solution using polyethylene glycol mono-p-nonylphenyl ether (PONPE 7.5) as extraction solvent in the presence of Cu(II) at pH 6.0. Variables influencing the UA-CPME extraction efficiency such as pH, metal type and amount, temperature, ultrasonic effect, solvent type, non-ionic surfactant type and concentration were optimised in detail. Under optimum conditions, the analytical properties of the developed method were as follows: linear working range, 20-750 μg L^-1; limit of detection, 6.5 µg L^-1; and the pre-concentration factor, 200. The relative standard deviation (RSD%) obtained for 50 µg L^-1 (n = 5) of Ponceau 4R was 2.9%. The accuracy and precision of the method were evaluated by intra-day and inter-day studies. Finally, the developed method has been successfully applied to the separation and identification of Ponceau 4R in the selected samples and the recoveries ranged from 94.3 to 104.2.

Self-assembled matrix fabricated by Fe-metal organic frameworks and carboxymethyl cellulose for the determination of small molecules by MALDI-TOF MS

A nanoprobe of laser desorption/ionization-time of flight mass spectrometry (LDI-TOF MS) for the determination of small molecules was developed that is based on the composition of Fe-metal organic frameworks (Fe-MOFs) and carboxymethyl cellulose-Na (CMC-Na). This material is a good adsorbent for small molecules via hydrogen bonding and π-interactions; we detected three molecules, dopamine, glyphosate, and pyrene. The detection limits for these compounds are 0.01 mg L^-1, 1.50 μg L^-1, and 0.01 μg L^-1, respectively; the recoveries are 85-117%, 81-127%, and 89-115%, respectively. The relative standard deviations (~ 15%) and coefficients of determination of the calibration plot (~ 0.97) are satisfactory. The applicability of the chip for practical samples is demonstrated by quantifying pyrene in domestic water and polluted lake water; the recoveries are about 90~117% and 85~125% (n = 5), respectively; the RSDs are 9.4% and 13.5%, respectively. Graphical abstract.

The impact of ultrasonic treatment on blueberry wine anthocyanin color and its In-vitro anti-oxidant capacity

Ultrasound (US) has been recognized as a non-thermal technology for accelerating blueberry wine aging for flavor development. However, influence of US on anthocyanin and color characteristics is uncertain. In this study, US was applied to new blueberry wine, and changes in color characteristics, anthocyanin content and anti-oxidant capacity were evaluated at early stage of aging period. Low-frequency power US resulted in an improvement in color characteristics and lower chromatic aberration as compared to untreated samples, specially at condition of 180 W, 20 min and 2 cycles. Furthermore, this contribution was attributed to unattenuated anthocyanins protected from US stress. Importantly, the structural polarity dependence was mediated by the impact of US on anthocyanins. Additionally, anti-oxidant activity of blueberry wine was not adversely affected under a moderate US condition. US treatment of blueberry wine was therefore considered to significantly enhance the color presentation, hinting at the possibility of promoting blueberry wine aging.

Optimization of staining with SYTO 9/propidium iodide: interplay, kinetics and impact on Brevibacillus brevis

Fluorophores SYTO 9 and propidium iodide (PI) are extensively applied in medicine, food industry and environmental monitoring to assess the viability of bacteria. However, the actual performance of these dyes remains largely unknown. In addition, their effects on the physiology of cells have not been elucidated. Here we characterized the effects of these two dyes on Brevibacillus brevis under optimized staining. We found that SYTO 9 entered cells continuously while PI tended to adhere to the cell wall before entering the cell. In addition, results showed that a high amount of the dyes altered the physicochemical properties of membranes, improving their breakthrough. These results provide new perspectives and ideas for improving the characterization of bacterial viability using flow cytometry.

Gold nano-flowers (Au NFs) modified screen-printed carbon electrode electrochemical biosensor for label-free and quantitative detection of glycated hemoglobin

Glycated hemoglobin (HbA1c) represents the average glucose level over the past three months and has been considered as the most important biomarker for the diagnosis of Type Ⅱ diabetes (T2D). Herein, a label-free and quantitative electrochemical biosensor based on 4-mercaptophenylboronic acid (4-MPBA) modified gold nano-flowers (Au NFs) substrate was developed for the determination of HbA1c. Under optimal conditions, the linear dynamic ranges of HbA1c (5 μg/mL - 1000 μg/mL) and HbA1c% (2%-20%) by cyclic voltammetry were achieved. The electrochemical biosensor showed great detection specificity towards HbA1c and relatively stability after storage at 4 °C. This method could also be applied in human serum system which holds great potential to be applied to monitor real blood samples of diabetes patients. In human serum system, the recovery rate could reach 103.8% and 99.0%. It could achieve fast detection, the total analysis time was less than 65 min, and the detection time was less than 10 s. Moreover, in terms of fabrication process, operation procedure, detection time and cost, this technique was superior to the current HbA1c detection methods suggesting great promise for the practical clinical use in the future.

Development of a chemiluminescent aptasensor for ultrasensitive and selective detection of aflatoxin B1 in peanut and milk

More and more attention about food safety leads to a research hotspot to develop new detection methods for food contaminant. To address the problems of serious interference and low sensitivity, a chemiluminescent aptasensor for the detection of aflatoxin B1(AFB1) in food was developed in this paper. It is based on horseradish peroxidase (HRP) catalyze the luminol chemiluminescence reaction. The hybridization chain reaction (HCR) signal amplification strategy has been used to improve the detection sensitivity. Magnetic separation could further reduce background signal obviously at the same time. AFB1 as a model of analyte to test the capability of our developed assay system. Under the optimal experimental conditions, CL intensity showed a good linear correlation with the concentrations of AFB1 ranging from 0.5 to 40 ng mL^-1. The limit of detection was estimated 0.2 ng mL^-1 based on 3 times of the signal-to-noise ratio which is lower than those of the previously reported sensors. It could be used to detect AFB1 content in real samples, such as peanuts and milk which were purchased in local supermarket. The results proved that the sensing system has good anti-interference and selectivity. In all, it has potential for practical application in food safety field.

A novel electrochemical sensor based on bimetallic metal-organic framework-derived porous carbon for detection of uric acid

We demonstrate a facile electrochemical sensor (CNCo/GCE) based on N,Co-doped porous carbon (CNCo) as electrode materials for detection of uric acid (UA). The porous carbon materials were prepared via the direct carbonization of bimetallic zeolitic imidazolate frameworks (BMZIFs) based on ZIF-8 and ZIF-67 with an appropriate molar ratio of Zn/Co at 900 °C in an N₂ atmosphere. The properties of the BMZIFs and CNCo were characterized by SEM, TEM, XRD, and XPS. The electrochemical behaviors of the CNCo-modified electrode were investigated using cyclic voltammetry (CV), impedance analysis (EIS), and differential pulse voltammetry (DPV) and showed enhanced electrochemical catalytic activity toward UA. DPV was conducted for the determination of UA with a linear range of 2.0-110 μM and a low detection limit of 0.83 μM at an S/N = 3. Furthermore, the CNCo/GCE electrode showed good reproducibility and repeatability with RSDs of 3.07% and 3.26%, respectively. Additionally, the sensor was successfully employed to quantify UA in human serum samples with satisfactory recoveries, suggesting it is a promising candidate for biological applications.

A multi-parallel N-glycopeptide enrichment strategy for high-throughput and in-depth mapping of the N-glycoproteome in metastatic human hepatocellular carcinoma cell lines

N-glycosylation is deeply involved in many biological processes, and approximately 50% of mammalian proteins are predicted to be glycosylated. Many large-scale studies have been carried out to reveal the glycosylation status involved in different physiological pathologies across species. However, the lack of a highly specific and high-throughput N-glycosylated enrichment method not only results in extended time requirements but also limits the depth of mapping when handling a large number of samples. In this study, we firstly optimized traditional zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) enrichment and found that using of 70% acetonitrile (ACN), 0.1% trifluoroacetic acid (TFA) as the enrichment buffer, 2800 g as the washing speed and 600 μL as the washing volume achieved the best specificity, which is higher than 75%. On this basis, we developed a multi-parallel enrichment strategy assisted by a filter-coated 96-well plate, which achieved high specificity and high throughput simultaneously. This strategy allowed us to enrich large numbers of fractionated samples from hepatocellular carcinoma (HCC) cell lines in less than 2 h. Its good specificity helped us achieve in-depth mapping of the N-glycoproteome in metastatic HCC cell lines. A total of 5466 N-glycosites from 2383 glycoproteins were identified, among which 1900 N-glycosites were unannotated in UniProt. The in-depth glycoproteome mapping provides insight into the N-glycosylation status in HCC cell lines with differences in metastatic potential and contributes to biomarker discovery.

Ultrasound-assisted dispersive magnetic solid phase extraction based on metal–organic framework/1-(2-pyridylazo)-2-naphthol modified magnetite nanoparticle composites for speciation analysis of inorganic tin

A novel magnetic metal–organic framework (MMOF) consisting of MIL-101(Cr) and 1-(2-pyridylazo)-2-naphthol-modified magnetite nanoparticles was synthesized and utilized for the ultrasound-assisted magnetic solid phase extraction and speciation analysis of Sn(ii) and Sn(iv) at trace amounts.

Synthesis of ion-imprinted polymer-decorated SBA-15 as a selective and efficient system for the removal and extraction of Cu(ii) with focus on optimization by response surface methodology

Ion-imprinted polymer-decorated SBA-15 (SBA-15-IIP) for the adsorption of copper was synthesized and characterized using different techniques, including FT-IR, XRD, TG/DTA, SEM, BET, and TEM.

Ultrasonically formation of supramolecular based ultrasound energy assisted solidification of floating organic drop microextraction for preconcentration of methadone in human plasma and saliva samples prior to gas chromatography-mass spectrometry

In this work, an ultrasonic-assisted supramolecular based on solidification of floating organic drop microextraction (UA-SM-SFO-ME) was developed as a green method for preconcentration of methadone prior to gas chromatography-mass spectrometry (GC-MS). The supramolecular solvent aggregates containing reverse micelles of 1-dodecanol in tetrahydrofuran (THF) were formed by ultrasonication that subsequently dispersed in the sample solution. Ultrasonic waves caused the fast formation of supramolecular solvent aggregates. In this work, ultrasonication was used in two phases: First phase, the formation of reverse micelles and the second phase, the dispersion of supramolecular solvent in the sample solution. Actually, ultrasonication was basic of this presented work. In order to provide the highest extraction efficiency, the influence of various parameters on the method performance (supramolecular solvent type and volume, disperser solvent condition, pH, extraction time and salt concentration) was investigated. Based on the obtained optimum conditions, the limits of detection (LODs) and the limits of quantitation (LOQs) were obtained 0.5-1.2 µg L^-1 and 1.2-2.5 µg L^-1 with preconcentration factors in the range of 182-191, in water and biological samples, respectively. Subsequently, the method was assessed for preconcentration of the methadone in human plasma and saliva samples.

Ultrasound-assisted dispersive liquid-liquid microextraction followed by ion mobility spectrometry for the simultaneous determination of bendiocarb and azinphos-ethyl in water, soil, food and beverage samples

A sensitive and fast ultrasound-assisted dispersive liquid-liquid microextraction procedure combined with ion mobility spectrometry has been developed for the simultaneous extraction and determination of bendiocarb and azinphos-ethyl. Experimental parameters affecting the analytical performance of the method were optimized: type and volume of extraction solvent (chloroform, 150 µL), pH (9.0), type and volume of buffer (ammonium buffer pH = 9.0, 4.5 mL) and extraction time (3.0 min). Under optimum conditions, the linearity was found to be in the range of 2-40 and 6-100 ng/mL and the limits of detection (LOD) were 1.04 and 1.31 ng/mL for bendiocarb and azinphos-ethyl, respectively. The method was successfully validated for the analysis of bendiocarb and azinphos-ethyl in different samples such as waters, soil, food and beverage samples.

Cu- and S- @SnO2 nanoparticles loaded on activated carbon for efficient ultrasound assisted dispersive µSPE-spectrophotometric detection of quercetin in Nasturtium officinale extract and fruit juice samples: CCD-RSM design

A simple, rapid, and efficient method of dispersive micro solid phase extraction (D-μ-SPE) combined with UV-Vis spectrophotometry via ultrasound-assisted (UA) was applied for the determination and preconcentration of quercetin in extract of watercress (Nasturtium officinale), fruit juice and water samples. The sorbent in this method was synthesized by doping copper and sulfide into the tetragonal structure of SnO₂-nanoparticles (Cu- and S- @SnO₂-NPs) and subsequently loading it on activated carbon (AC). The D-μ-SPE parameters with direct effect on the extraction efficiency of the targeted analyte, such as sample pH, volume of eluent, sorbent mass and ultrasound time were optimized using central composite design method. Under optimized conditions, the calibration graph for quercetin was linear in the range of 20-4000 ng mL^-1; the limit of detection and quantitation were 4.35 and 14.97 ng mL^-1, respectively and the enrichment factor was 95.24. Application of this method to analyze spiked extract, fruit juice and water samples resulted in acceptable recovery values ranging from 90.3% to 97.28% with intra-day and inter-day relative standard deviation values lower than 6.0% in all cases. Among the equilibrium isotherms tested, Langmuir was found to be the best fitted model with maximum sorption capacity of 39.37 mg g^-1, suggesting a homogeneous mode of sorption for quercetin.

Rapid and selective luminescent sensing of allergenic gluten by highly phosphorescent switch-on probe

First time the luminescent switch-on probe using novel water-soluble cyclometallated iridium complex (Ir-dc) has been developed for sensitive and selective detection of gluten in the presence of several interfering elements. Linear concentration range of gluten is obtained from 5 to 200 µg/mL with a limit of detection 2.6 µg/mL. The Ir-dc complex responded to the broad pH range which is advantageous for the detection of gluten in various food samples. Additionally, It has been successfully employed for the detection of gluten in commercial food samples of wheat flour and oats with highest recovery values, indicating applicability of Ir-dc for practical usage.

Oil removal from spent HDT catalyst by an aqueous method with assistance of ultrasound

Deoiling enjoys great significance in recycling and landfill of spent hydrotreating (HDT) catalyst. In this study, a novel approach for oil removal from spent HDT catalyst with assistance of ultrasound was developed. The effects of variables on oil removal were investigated by response surface methodology and central composite design method. The oil removal efficiency reaches 96.03 ± 0.82% under the optimum conditions of liquid-solid ratio 16.00 ml·g^-1, 75 °C, sodium hydroxide dosage 3.88 wt%, and 40 kHz ultrasonic irradiation for 3.25 h. Under the optimum conditions, the contact angle of spent catalyst is 98.7° before oil removal, and then reduces to 57.2° after deoiling with the help of ultrasound, but turns to 72° after deoiling in the absence of ultrasound, which further verifies that the oil removal efficiency can be improved by ultrasound. Compared to traditional extraction or hydrothermal methods for removing oil from spent catalyst, the proposed approach introduced ultrasonic force field to enhance oil removal efficiency without adding organic solvent or surfactant.

Ultrasonically synthesis of Mn- and Cu- @ ZnS-NPs-AC based ultrasound assisted extraction procedure and validation of a spectrophotometric method for a rapid preconcentration of Allura Red AC (E129) in food and water samples

This study is devoted on Allura Red as food colorant preconcentration and determination in beverage, fruit juice and drink water samples is based on usage of Mn- and Cu- @ ZnS-NPs-AC as new sorbent for ultrasound-assisted-dispersive solid-phase microextraction (UA-DSPME) combined with ultraviolet-visible spectrophotometric based method (UV-Vis). Contribution of volume of eluent, pH, sorbent mass and sonication time on response following conduction of 28 experiments were optimized and investigated while their significantly justified according to p-value. Values of "Prob > F" less than 0.0500 is proportional with their significant influence on recovery of analyte. Under the optimum conditions 0.14 mL of THF; pH of 2.5; 8 mg of sorbent and 3 min sonication time guide and help achievement of limit of quantification (LOQ) and limit of detection (LOD) of 6.08 and 20.26 ng mL^-1, respectively. The accuracy of method was validated according to calculation of recovery following spiking 400 and 600 ng mL^-1 to blank solution and recovery as more reliable indication of accuracy 93.41 and 102.17% recoveries with RSD < 3.5%, which demonstrate the successful applicability of present method for real sample analysis. The maximum sorbent capacity was 50.0 mg g^-1 based on Langmuir isotherm as best model with high correlation coefficient. Combination of UA-DSPME and UV-Vis lead to higher sensitivity and lower cost for accurate and repeatable monitoring of Allura Red level in beverage, fruit juice and drink water samples with acceptable recovery and reasonable RSD%.

Ultrasound-assisted liquid–liquid spray extraction for the determination of multi-class trace organic compounds in high-volume water samples

A premier analytical method for the determination of multi-class trace organic compounds in high-volume water matrices.

Optimization of process parameters for determination of trace Hazardous dyes from industrial wastewaters based on nanostructures materials under ultrasound energy

In this study, ultrasound-assisted dispersive solid phase micro-extraction based on nanosorbent namely silver-zinc oxide nanoparticles loaded on activated carbon (Ag-ZnO-NP-AC) combined with derivative spectrophotometry method for the simultaneous pre-concentration and determination of Methyl Green (MG) and Rose Bengal (RB) dyes in water and industrial wastewater. Characterized sorbent by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), particle-size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM) analysis with superior adsorption capacity was applied in ultrasound assisted dispersive-solid-phase micro-extraction (UA-DSPME) methodology. pH, sorbent mass, ultrasonication time, and eluent volume influence and contribution on response correspond to simultaneous pre-concentration and determination of MG and RB were optimized by response surface methodology (RSM) and results were compared with the experimental values. Under the optimal conditions (UA-DSPME), the enrichment factors (EFs) were 93.89 and 97.33 for the MG and RB dyes, respectively. The limits of detection were 2.14 and 2.73ngmL^-1 and the limit of quantification were 7.15 and 9.09ngmL^-1 for MG and RB, respectively. The analytes can be determined over 10-2000ngmL^-1 with recoveries between 90.8% to 97.7% and RSDs less than 3.6%. The developed method due to simplicity and rapidity is able successful for repeatable and accurate monitoring of under study analytes from complicated matrices.

Development of an eco-friendly approach based on dispersive liquid–liquid microextraction for the quantitative determination of quercetin inNasturtium officinale,Apium graveolens,Spinacia oleracea,Brassica oleracea var. sabellica, and food samples

A fast, sensitive, inexpensive and environment-friendly dispersive liquid–liquid microextraction technique was developed based on solidification of floating organic drops.