Amount Of Sorbent Research Articles

Synthesis of Functionalized Pyridine Modified Magnetic Nanoparticles for Utilization in Magnetic Solid‐Phase Extraction of Tebuconazole and Propiconazole Followed by Quantification via High‐Performance Liquid Chromatography‐Ultraviolet Detection

ABSTRACTIn the current study, a new magnetic sorbent (Fe3O4@2,6‐diamino‐4‐(3,4‐dihydroxyphenyl) pyridine‐3,5‐dicarbonitrile) was prepared as a new and efficient sorbent to be used in the magnetic solid‐phase extraction method to extract tebuconazole and propiconazole as model compounds. In this regard, effective parameters such as pH of the sample solution, desorption volume, ionic strength, extraction time, desorption time, and amount of the magnetic sorbent were optimized using experimental design. In the optimal condition, the linear dynamic ranges for tebuconazole and propiconazole were between 0.5 and 200.0 µg/L. Also, the limits of detection, limits of quantification, and relative standard deviations were 0.21–0.14 µg/L, 0.49–0.45 µg/L, and 1.3%–4.6%, respectively. The estimated enrichment factors for tebuconazole and propiconazole were 22 and 28, respectively. The absolute recovery (AR%) values for tebuconazole and propiconazole were also 67% and 84%, respectively. Finally, the proposed method was used for determination of tebuconazole and propiconazole in cucumber, tomato, orange, and lemon fruits. The obtained result confirmed that the presented method is capable for the analysis of the selected analytes in complicated matrices. In addition, the ARs% were in the range of 67%–84%. The result proved that the presented method can be an alternative to the extraction process of various pesticides.

The Environmental Stake of Bitcoin Mining: Present and Future Challenges

The environmental impact of Bitcoin mining has raised severe concerns considering the expected growth of 30% by 2030. This study aimed to develop a Life Cycle Assessment model to determine the carbon dioxide equivalent emissions associated with Bitcoin mining, considering material requirements and energy demand. By applying the impact assessment method IPCC 2021 GWP (100 years), the GHG emissions associated with electricity consumption were estimated at 51.7 Mt CO2 eq/year in 2022 and calculated by modelling real national mixes referring to the geographical area where mining takes place, allowing for the determination of the environmental impacts in a site-specific way. The estimated impacts were then adjusted to future energy projections (2030 and 2050), by modelling electricity mixes coherently with the spatial distribution of mining activities, the related national targeted goals, the increasing demand for electricity for hashrate and the capability of the systems to recover the heat generated in the mining phase. Further projections for 2030, based on two extrapolated energy consumption models, were also determined. The outcomes reveal that, in relation to the considered scenarios and their associated assumptions, breakeven points where the increase in energy consumption associated with mining nullifies the increase in the renewable energy share within the energy mix exist. The amount of amine-based sorbents hypothetically needed to capture the total CO2 equivalent emitted directly and indirectly for Bitcoin mining reaches up to almost 12 Bt. Further developments of the present work would rely on more reliable data related to future energy projections and the geographical distribution of miners, as well as an extension of the environmental categories analyzed. The Life Cycle Assessment methodology represents a valid tool to support policies and decision makers.

Magnetic particle spray mass spectrometry for the determinationof beta-blockers in plasma samples.

Magnetic particle spray mass spectrometry (MPS-MS), an innovative ambient ionization technique proposed by our research group, was employed to determine beta-blockers in human plasma samples. A dispersive solid phase extraction of atenolol, metoprolol, labetalol, propranolol, nadolol, and pindolol was carried out using magnetic molecularly imprinted polymer (M-MIP) particles that were attached to the tip of a metal probe, which was placed in the mass spectrometer inlet. A solvent (1% formic acid in methanol) was dispensed on the particles, and the Taylor cone was formed around them (in high voltage). The analytes were desorbed/ionized and determinedby a triple quadrupole mass spectrometer. M-MIP was synthesized with oxprenolol as a pseudo-template, demonstrating good selectivity to beta-blockers compared withno-analog molecules, with an adsorption process occurring in monolayers, according to isotherm studies. Kinetic experiments indicated chemisorption as the predominant M-MIP/analyte interaction. The analytical curves were linear (R2 > 0.98), and the limit of quantification was 3µg L-1 for all the analytes. Limits of detection ranged from 0.64 to 2.41µg L-1. Precisions (relative standard deviation) and accuracies (relative error) ranged from 3.95 to 21.20% and-17.05 to 18.93%, respectively. MPS-MS proved to be a simple, sensitive, and advantageous technique comparedwithconventional approaches. The analyses were fast, requiring no chromatographic separation and without ionic suppression. The method is aligned with green chemistry principles, requiring minimal sample, solvent, and sorbent amounts. MPS-MS successfully integrates sample preparation and ambient ionization mass spectrometry and holds great potential for application with other sorbents, samples, and analytes.

Multivariate optimization of the extraction and cleaning procedure to determine neonicotinoids in honey from intensive livestock and agricultural production areas by UHPLC-MS/MS

Neonicotinoid insecticides have been associated with the decline of bee population. This study aimed to investigate the occurrence of neonicotinoids in honey samples from apiaries located in areas of intensive livestock and agricultural production in Argentina. For this purpose, a QuEChERS-based analytical method was developed and optimized using multivariate strategies to reduce the processing time and the necessary amount of salts and sorbents. Validation was based on SANTE 11312/2021 guidelines, with recovery percentages between 79 and 120 %, and limits of quantitation between 0.25 and 1.00 µg kg−1. The present study provides a highly sensitive and reliable method for ascertaining residue levels of eight insecticides in 151 honey samples using liquid chromatography coupled to mass spectrometry (UHPLC-MS/MS). The presence of three of the target analytes was determined in 13 % of the samples, indicating that honey bee colonies were exposed to neonicotinoids, especially imidacloprid and thiamethoxam. The maximum residue limits were not exceeded in any of the samples; therefore, there is no risk to consumers from the public health point of view.

Cellulose-based nanostructured aerogels for leachate decontamination: Towards sustainable phosphorus recovery from sewage sludge ash

Recent EU data confirmed phosphorus as a critical raw material, with efficient recovery from sewage sludge ash presenting challenges, particularly due to the co-dissolution of heavy metals. This work investigated an innovative strategy for the removal of heavy metals from sewage sludge ash derived leachate by using sustainable cellulose nanosponges, synthetized by thermal cross-linking between branched polyethylenimine and 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose nanofibers.Lab-scale adsorption tests were conducted with varying sorbent amounts (1, 3 and 10 g/L) in absence or presence of citric acid (10 g/L) across pH values (1.8–10), to assess the removal of metals/metalloids (As, Cu, Cr, Ni, Zn, Fe, Al). P was subsequently precipitated from the decontaminated leachate by adding Ca(OH)2 till target pH.Results showed that cellulose nanosponges were able to adsorb considerable amounts of metallic ions, in particular Fe and Al, under strongly acidic conditions, reducing their percentage by 40% and 30%, respectively. Under optimized conditions (10 g/L of citric acid and 10 g/L of sorbent), the solid precipitate recovered at pH 8 from the decontaminated leachate was compliant with EU regulation 2019/1009 in terms of P2O5 and heavy metals content, suggesting its possible future use as raw material for inorganic fertilizers production.

Uptake of uranium(VI) upon a novel developed nanocomposite of bimetallic Mg/Mn bentonite lupine peels

In this work, a new green nanocomposite material was synthesized, characterized, and implemented for the removal of Uranium(VI) from nuclear waste solution. The nanocomposite material consisted of bimetallic Mg/Mn-Tartaric intercalated with bentonite and functionalized with lupine peel biochar through a refluxing process with a mixed solution of water and formaldehyde (3:1). The synthesized nanocomposite and the pristine materials were characterized using FTIR, and XRD, and the thermal stability of all the components was investigated using TGA. Finally, the morphology of the synthesized materials was investigated using SEM images. The adsorption was studied through different parameters: different pH values, sorption time, different amounts of sorbent, and different uranium concentrations. In addition to the adsorption studies, the desorption studies and the elution process were also investigated. It was found that the maximum adsorption value at pH 4.0 and 60.0 min as about 113.90 mg·g−1, the kinetics fit with pseudo second-order, and the adsorption was fitted with the Langmuir model. Finally, the desorption study was established, and the effective eluting agent was Na2CO3, with an elution efficiency of about 97.4 %.

Adsorption Separation of Various Polar Dyes in Water by Oil Sludge-Based Porous Carbon

The pollution caused by printing and dyeing wastewater is increasingly severe, posing significant harm to aquatic plants and animals. In this study, porous carbon was synthesized via the high-temperature pyrolysis of light and heavy organic matter present in oily sludge, utilizing low oil content sludge as the raw material and zinc chloride as a chemical activator. The results exhibited a significant increase in the specific surface area of the oily sludge-based porous carbon, from 4.95 m²/g to 10.95 m²/g. The effects of various parameters such as pH, amount of sorbent, dye concentration, temperature, and contact time on dye removal have been studied. The results showed that the oil sludge-based porous carbon exhibited high efficiency in removing Malachite Green from aqueous solutions, which has low polarity and remains consistently above 97%. The removal rate of Crystal Violet, which is more polar, was as low as 24.14%. The corresponding adsorption capacities were 33.41 mg/g for Malachite Green, 16.41 mg/g for Crystal Violet, and 13.56 mg/g for Methylene Blue. The adsorption capacity of OSC700 for three types of dyes was characterized by monolayer adsorption, primarily driven by chemical adsorption, with significant contributions from electrostatic and hydrophobic effects. The adsorption process was spontaneous, exothermic, and accompanied by an increase in entropy. For less polar substances, the adsorption on oily sludge-based porous carbon is primarily driven by aromatic functional groups on the carbon surface, hydrophobicity, π-π electron-donor-acceptor (π-π EDA) interactions, and surface hydrogen bond formation. In contrast, for more polar dyes, electrostatic and hydrophobic interactions dominate, with electrostatic adsorption being the predominant mechanism and minimal hydrogen bond formation during adsorption.

Seaweed Superheroes: Cystoseira barbata-Incorporated Electrospun Fibers for Lead Ion Sequestration.

The efficient removal of lead ions at low concentrations is paramount in combating the significant threat posed by water pollution resulting from industrial activities and population growth. In this study, electrospun C. barbata/PAN fibers were developed to efficiently remove lead(II) ions from water. The morphology, structure, and mechanical properties of the fibers were examined, highlighting that the augmentation of the surface area through the conversion of C. barbata into the polymer fibers facilitates increased metal bonding sites during sorption. C. barbata/PAN fibers exhibited superior characteristics, including higher surface area, smaller pore size, and increased pore volume, compared to powdered C. barbata. The effects of factors such as shaking time, algae percentage, sorbent amount, pH, metal concentration, and temperature on Pb(II) sorption were investigated by the batch method. At an initial ion concentration of 100 μg L-1 and pH 4.0, C. barbata (5 wt %)/PAN fiber demonstrated a notable sorption efficiency of 89-90% (270 μg/g) after 60 min. The equilibrium data align with the Freundlich and Dubinin-Radushkevich isotherm models, whereas the pseudo-second-order kinetic model provides the most suitable description. The characterization of fibers after sorption revealed that carboxyl, hydroxyl, and sulfonyl groups play an active role in Pb(II) sorption.

Dispersive micro Solid-Phase extraction with Bimetallic Ni, Zn-MOF sorbent and gas chromatography method for Organophosphorus pesticide determination in environmental water samples

A dispersive micro solid-phase extraction coupled with the GC-FID method was developed to determine three Organophosphorus pesticides: Fenitrothion, Chlorpyrifos, and Diazinon. Various sorbents, including Fe3O4 NPs, Zn-MOF, Ni-MOF, Bimetallic Ni, Zn-MOF, and Fe3O4 NPs@SiO2@ Bimetallic Ni, Zn-MOF, were synthesized and evaluated for their extraction efficiency of OPPs. Fe3O4 NPs@SiO2@ Bimetallic Ni, Zn-MOF was identified as the optimal sorbent based on its performance. The affective factors in the procedure were optimized using one factor of the time and experimental design methods. The significant factors in this method included sorbent amount, extraction time, and desorption solvent volume with an optimum value of 37 mg, 8.3 min, and 231 µL, respectively. Under optimized conditions, the method exhibited distinct linear ranges for Fenitrothion, Chlorpyrifos, and Diazinon, ranging from 0.24 to 259, 0.17–234, and 0.25–247 ng mL−1, respectively, with high corresponding R2 values (0.9947, 0.9929, and 0.9943). The limits of detection (LOD) were determined based on three times the standard deviation of the blank sample divided by the slope of the calibration curve for each OPP to be 0.07, 0.05, and 0.07 ng mL−1 for Fenitrothion, Chlorpyrifos, and Diazinon, respectively, while the limits of quantification (LOQ) were 0.24, 0.17, and 0.25 ng mL−1. Precision was assessed by calculating intra-day and inter-day relative standard deviation (RSD%) values in one day and three consecutive days with three replicates of each analysis for three concentrations of 10, 25, and 50 ng mL−1, which were found to be below 4.27 %, 4.35 %, and 4.32 % for Fenitrothion, Chlorpyrifos, and Diazinon, respectively, for intra-day analysis, and below 5.43 %, 5.11 %, and 5.29 % for inter-day analysis, respectively. Additionally, the enrichment factor (EF) values for Fenitrothion, Chlorpyrifos, and Diazinon with a concentration of 20 ng mL−1 were determined to be 78.6, 82.4, and 75.7, respectively. Analysis of spiked real samples in two concentrations of 5.0 or 25.0 ng mL−1, such as tap water, river water, dam water, and well water, revealed recovery percentages in the range of 91.2 % to 97.7 %, with relative standard deviations ranging from 3.79 % to 4.98 %, further validating the method’s reliability for practical applications. Overall, the method provides wide linearity, low LODs and LOQs, responsible RSDs, high EFs, and proper recovery percentages for determining OPPs.

Multiclass Analysis for the Determination of Pharmaceuticals and Their Main Metabolites in Leafy and Root Vegetables.

The irrigation of soils with reclaimed contaminated wastewater or its amendment with sewage sludge contributes to the uptake of pharmaceuticals by vegetables growing in the soil. A multiresidue method has been devised to determine five pharmaceuticals and nine of their main metabolites in leafy and root vegetables. The method employs ultrasound-assisted extraction, clean-up via dispersive solid-phase extraction, and analysis through liquid chromatography-tandem mass spectrometry. Box-Behnken design was used to refine variables such as extraction solvent volume, time of extraction, number of extraction cycles, and the type and amount of d-SPE sorbent. The method achieved linearity (R2) greater than 0.994, precision (relative standard deviation) under 16% for most compounds, and detection limits ranging from 0.007 to 2.25 ng g-1 dry weight. This method was applied to a leafy vegetable (lettuce) and to a root vegetable (carrot) sourced from a local market. Parent compounds were detected at higher concentrations than their metabolites, with the exception of carbamazepine-10,11-epoxide.

OLIVE PITS-BASED CARBON BLACK AGGLOMERATE AS AN ADSORBENT FOR PIPETTE-TIP SOLID-PHASE EXTRACTION FOR THE DETERMINATION OF CAFFEINE IN ENERGY DRINKS

Vegetal wastes are an interesting source for the synthesis of nanostructured carbon materials, which are potentially useful in various applications. Carbon black agglomerates (CBA) obtained from olive pits, synthesized in our previous research, had a low crystalline structure typical of this type of materials, with a pore size of 2.27 nm, confirming their micro/mesoporous structure, and with a high surface value of around 587 m2/g. These materials were used for the extraction of caffeine in energy drinks using a green-approach micro-sample technique called pipette-tip solid-phase extraction. This microextraction technique features reduced consumption of organic solvents, of the amount of sorbent and extraction time, thus making the whole sample pretreatment process faster and greener. In this work, we proposed an analytical method for the analysis of caffeine in commercial energy drinks, using CBA with a great extraction capacity due to its high porous surface area. The developed methodology has proven to be useful from a green chemistry point of view, using only one milligram of nanostructured sorbent, minimal solvent consumption, a reduced volume of sample, as well as easy and rapid automatization for the analysis of commercial energy drinks. For the quantification of the analyte in the energy drinks, a one-point standard addition calibration was applied to correct the matrix effect. Similar caffeine concentrations per milliliter were found in the three analyzed samples, likewise, the amounts of caffeine close to those reported by the manufacturers were established for two of the samples analyzed.

Novel Application of Metal-Organic Frameworks as Efficient Sorbents for Solid-Phase Extraction of Chemical Warfare Agents and Related Compounds in Water Samples.

In this work, we test metal-organic frameworks (MOFs) as sorbents in the solid-phase extraction (SPE) technique to determine chemical warfare agents (CWAs) and their related compounds in water samples. During this study, we used 13 target compounds to test the selectivity of MOFs thoroughly. Three MOFs were used: MIL-100(Fe), ZIF-8(Zn), and UiO-66(Zr). The obtained materials were characterized using FT-IR/ATR, SEM, and XRD. CWA's and related compounds were analyzed using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The effect of the type of elution solvent and the amount of sorbent (MOFs) in the column on the efficiency of the conducted extraction were verified. The LOD ranged from 0.04 to 7.54 ng mL-1, and the linearity range for the analytes tested extended from 0.11/22.62 (depending on the compound) to 1000 ng mL-1. It was found that MOFs showed the most excellent selectivity to compounds having aromatic rings in their structure or a "spread" spatial structure. The best recoveries were obtained for DPAA, CAP, and malathion. Environmental water samples collected from the Baltic Sea were analyzed using an optimized procedure to verify the developed method's usefulness.

Advancing hydrogen generation: Kinetic insights and process refinement for sorption-enhanced steam gasification of biomass utilizing waste carbide slag

Sorption enhanced steam gasification of biomass (SESGB) presents a promising approach for producing high-purity H2 with potential for zero or negative carbon emissions. This study investigated the effects of gasification temperature, CaO to carbon in biomass molar ratio [CaO/C], and steam flow on the SESGB process, employing carbide slag (CS) and its modifications, CSSi2 (mass ratio of CS to SiO2 is 98:2) and CSCG5 (mass ratio of CS to coal gangue (CG) is 95:5), as CaO-based sorbents. The investigation included non-isothermal and isothermal gasification experiments and kinetic analyses using corn cob (CC) in a macro-weight thermogravimetric setup, alongside a fixed-bed pyrolysis-gasification system to assess operational parameter effects on gas product. The results suggested that CO2 capture by CaO reduced the mass loss during the main gasification as the [CaO/C] increased. The appropriate temperature for SESGB process should be selected between 550 and 700 °C at atmospheric pressure. The appropriate amount of sorbent or steam could facilitate the gasification reaction, but excessive addition led to adverse effects. Operational parameters influenced the apparent activation energy (Ea) by affecting various gasification reactions. For each test, Ea at the char gasification stage was significantly higher than that at the rapid pyrolysis stage. The addition of CS notably increased H2 concentration and yield, while sharply reducing CO2 levels. H2 concentration initially rose and then fell with greater steam flow, peaking at 76.11 vol% for a steam flow of 1.0 g/min. H2 yield peaked at 298 mL/g biomass with a steam flow of 1.5 g/min, a gasification temperature of 600 °C and a [CaO/C] of 1.0. Increasing gasification temperature remarkably boosted the H2 and CO2 yields. Optimal conditions for the SESGB using CS as a sorbent, determined via response surface methodology (RSM), include a gasification temperature of 666 °C, a [CaO/C] of 1.99, and a steam flow of 0.5 g/min, under which H2 and CO2 yields were 464 and 48 mL/g biomass, respectively. CSSi2 and CSCG5 demonstrated excellent cyclic H2 production stability, maintaining H2 yields around 440 mL/g biomass and low CO2 yields (∼60 mL/g biomass) across five cycles. The study results offer new insights for the high-value utilization of agroforestry biomass and the reduction and resource utilization of industrial waste.

Development of a sustainable adsorption system based on alginate-encapsulated clay for pharmaceutical pollutant capture in aqueous solution using Box–Behnken methodology

Our study focused on the removal of metformin in aqueous solution. Metformin, an antidiabetic drug, is increasingly detected in wastewater. This study explored the feasibility of using bentonite encapsulated in sodium alginate as a sustainable and efficient sorbent for metformin removal. The adsorbent was characterized by RAMAN, Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), electron-dispersive spectrometer (EDS), and point of zero charge (pHzc). The adsorbent contains various functional groups including hydroxyl (-OH) groups from both bentonite and sodium alginate, carboxyl (-COOH) groups from sodium alginate, and silanol (-Si-OH) groups from bentonite. Batch kinetic studies were carried out as a function of pH, metformin concentration, sorbent amount, and solution temperature. The Freundlich and Langmuir models were used to describe the isotherm data. The maximum monolayer adsorption capacity of the sorbent material was 19,19 mgg−1. The pseudo-second order kinetic model adequately describes the kinetic data. The negative ΔH (−35,253 kJmol−1) confirms an exothermic process, which is further supported by the negative Gibbs energy values (−0,489 to −3,668 kJmol−1), indicating spontaneity and reversibility. Moreover, ΔS° = −0.105 kJ/mol−1.K−1. Response surface methodology was employed to identify the optimal parameters for metformin removal. These parameters were found to be: pH of 6.34, metformin concentration of 5.4 mgL−1, and adsorbent dosage of 3 g L−1 resulted in a remarkable efficiency of 94%. Additionally, bentonite beads (BBs) maintained a significant adsorption capacity for up to three cycles, demonstrating promising reusability. This study highlights that the encapsulation of clay in sodium alginate is a sustainable and effective approach for removing metformin during water treatment.

Synthesis of green nanosorbent from bovine serum albumin and curcumin for magnetic solid phase extraction of pesticides from food samples

For the first time, a magnetic carbon nanocomposite was synthesized using one-step hydrothermal procedure, employing bovine serum albumin, curcumin, and ferric ammonium citrate. Additionally, the application of this novel composite as an adsorbent for magnetic dispersive solid phase extraction of fungicides and pesticides from water and food samples is a unique aspect of this study. Under optimum conditions (salt concentration: 5.0% w/v, pH: 7.0, desorption solvent: ethanol, sorbent amount: 20 mg, extraction time: 20 min, desorption time: 3 min, stirring rate: 500 rpm, sample volume: 30 mL, extraction temperature: room temperature, and desorption solvent volume: 150 μL) linearity (2.5 to 1400 ng mL−1), coefficients of determination (R2 ≥ 0.997), limits of detection (0.75 to 1.5 ng mL−1), and limits of quantification (2.5 to 5.0 ng mL−1) were achieved. The method validation results showed extraction recovery ranging from 71.2% to 93.4%, and preconcentration factors ranging from 142.5 to 186.1.

Sorption of three PAHs profile groups using eco-friendly and inexpensive hydroxyapatite extracted from camel bone

Hydroxyapatite (HAp) was used in the sorption study for three different polycyclic aromatic hydrocarbons (PAHs) ring structures (Naphthalene (NAP), Anthracene (ANT), and Chrysene). HAp powders were produced from Camelus bone as an eco-friendly and inexpensive source. Three distinct surface areas (66.56, 94.88, and 94.35 m2/g) at three different temperatures (500, 650, and 900 °C), were applied to prepare the HAp500, HAp650, and HAp900 samples after passing CO2 at 700 °C. It was obvious that the surface area of HAp was greatest at 650 °C as compared to 500 °C with a very small variation in uptake between HAP650 and HAP900. Furthermore, for ANT, HAp900 provides the best uptake. In addition, HAp650 is the best since calcining at 650 °C is less expensive than calcining at 900 °C. The effect of shaking time on the sorption of NAP, ANT, and CHR dissolved in n-hexane was carried out using HAp650. The impacts of sorbent amount, concentration, and temperature were studied. The study indicated that the uptake was 66.89, 69.49, and 19.67 mg/g after 120 min of equilibration. It was observed that the uptake of NAP, ANT, and CHR increased as the temperature increased up to 35 °C. A slight increase was obtained from 35–55 °C, indicating that the adsorption occurring on the HAp650 surface is endothermic. The positive values of Δ H demonstrated the endothermic nature of the adsorption process. Furthermore, the positive entropy of adsorption represents the adsorbent material’s affinity for NAP, ANT, and CHR. In addition, several isotherm models were used to deduce an adsorption mechanism. The adsorption system’s R2 values were 0.9615 for NAP, 0.8666 for ANT, and 1.00 for CHR. These values agree well with the Langmuir isotherm.

Melamine sponges incorporated azo-linked porous organic polymer as adsorbent for extraction and determination of six B vitamins using pipette tip micro solid-phase extraction

A novel azo-linked porous organic polymer (AL-POP) was synthesized from caffeic acid and benzidine via an azo-coupling reaction and characterized by FTIR, SEM-EDS, BET, TGA, XRD and zeta potential analysis. AL-POPs were incorporated into melamine sponges and used for pipette tip micro solid-phase extraction (PT-MSPE) of six types of B vitamins (including thiamine, riboflavin, nicotinamide, pyridoxine, folic acid, and cyanocobalamin). After extraction, the samples were analyzed using high performance liquid chromatography-diode array detection (HPLC-DAD) system. The effect of AL-POP composition on the extraction efficiency (EE) of vitamins was investigated and benzidine to caffeic acid mol ratio of 1.5, 3.35 mmol of NaNO2, and reaction time of 8 h were selected as optimum conditions. The efficiency of the extraction process was improved by optimizing various parameters such as the amount of sorbent, pH and ionic strength of the sample, sample volume, number of sorption and desorption cycles, type of wash solvent, and type and volume of eluent solvent. Linearity (R2≥0.9987), Limit of detection (LOD) (11.88–18.97 ng/mL), limit of quantification (LOQ) (39.62–63.23 ng/mL), and enrichment factor (EF) (1.27–4.31) were obtained using calibration curves plotted under optimum conditions. Recovery values of these six B vitamins in the spiked multivitamin syrup samples varied from 80.01% to 108.35%, with a relative standard deviation (RSD) below 5.44%. Eventually, the optimized method was successfully used to extract and quantify the B vitamins in multivitamin syrup and non-alcoholic beer.

Preconcentration of Cu2+, Cr3+, Co2+, and Ni2+ by Solid-Phase Extraction Using a Recently Developed Mixed-Mode Sorbent

The enrichment and simultaneous analysis of Cu2+, Cr3+, Co2+, and Ni2+ by solid-phase extraction method were performed using a stationary phase containing amide functional groups, an aromatic benzene ring, and aliphatic groups in a silica-based structure that we had synthesized for HPLC separations in our previous studies. Solid-phase extraction was performed using a column system and the results obtained were analysed by ICP-OES. Effects of pH, amount of sorbent, amount of eluting solvent, sample volume, flow rates of the eluent and the sample, and interfering ions were evaluated in recovery processes for the metals in the sample solutions. Linear range, detection limit, and relative standard deviation (% RSD) values were calculated for each metal. The linear range (ng/mL) was between 0.01 and 0.25 for all ions, while the limit of detection (ng/mL) was found to be 0.64, 1.7, 0.44, and 0.51 and % RSD was 2.8, 2.4, 2.6, and 2.9 for Cu2+, Cr3+, Co2+, ve Ni2+, respectively.

Optimization of an analytical method based on miniaturized matrix solid-phase dispersion combined with gas chromatography-mass spectrometry for the determination of bisphenols in mussel samples

In this study, a new method has been optimized to determinate nine bisphenols (BPs) in mussel samples. This approach is based on miniaturized matrix solid-phase dispersion combined with gas chromatography-mass spectrometry determination after trimethylsilylation with 99% N,O-Bis-(trimethylsilyl)trifluoroacetamide + 1 % trimethylchlorosilane. The optimization process investigated the derivatization (derivatizing agent volume, time and temperature) and sample preparation (C18 co-column packed and C18 dispersant agent amounts and elution volume) parameters. A second clean-up step was performed using EMR-Lipid cartridges in order to efficiently remove lipids from mussel, the optimized parameters were Captiva EMR-Lipid sorbent amount and elution volume. The whole method was validated and very good linearity (r2 > 0.99) was obtained. The recoveries (accuracy) at two concentration levels ranged from 51.2 to 109 % and the coefficients of variation (precision) were between 0.55 and 13 %. The limits of quantification were between 0.014 μg/Kg dry weight for BPM and 4.0 μg/Kg dry weight for BPS. The analytical procedure was applied to four mussel samples from Galician Rías. Except for one of four samples whose BPAF level was below the limit of quantification, all BPs were found in concentrations that ranged from 0.39 to 301 μg/Kg dry weight.

Magnetic iron-based metal organic framework as an adsorbent for magnetic dispersive solid-phase extraction of pyrene and phenanthrene in water samples

ABSTRACT A dispersive magnetic solid-phase extraction by means of core-shell iron-based metal-organic framework (Fe3O4- SiO2/EN@MIL-101(Fe)) nanospheres coupled with high-performance liquid chromatographic was developed for the determination of pyrene (Pyr) and phenanthrene (Phe) in water samples. Key parameters such as sorbent amount, sample volume, pH, extraction time, type and volume of elution, and desorption time were optimised by response surface methodology (RSM). Under the optimised conditions (sample volume: 5 mL, extraction time: 3 min, eluent: 3 mL acetonitrile: propanol, and desorption time: 3 min), the developed method showed a low detection and quantification limits (0.015 and 0.040 ng mL−1, respectively), good precision (< 9.8% RSD), wide linear range (0.06 - 10,000 ng mL−1, R2 > 0.99), high enrichment factors (49–57), good matrix effect (> 93.2%), high reusability (25 times), short extraction and desorption time (3 and 3 min, respectively), and high extraction recovery (96.5%). The established method was able to recover the Pyr and Phe from spiked real water samples with an extraction efficiency of 95.71% and 96.32%, respectively (RSD ≤ 9.52%).