A rapid, sustainable, and efficient analytical method based on Rotating Disk Sorptive–Dispersive Extraction (RDSDE) coupled to HPLC–DAD was developed and validated for the determination of florfenicol in animal plasma. The method employs a magnetic activated carbon (MAC) sorbent derived from avocado seed, an agricultural waste material, combining high extraction efficiency with improved environmental performance. Key extraction parameters were optimized, achieving optimal conditions with 20 mg of MAC, an extraction time of 20 min, and acetone as desorption solvent with a desorption time of 5 min.The method was fully validated in porcine plasma, demonstrating excellent selectivity, linearity (R² ≥ 0.9967), precision (RSD ≤ 7.2%), and accuracy (recovery ≥ 91%) over the concentration range of 0.5–10 mg L⁻¹. Dilution integrity was confirmed up to 20 mg L⁻¹, and robustness was demonstrated with respect to sorbent batch variability. Applicability to bovine plasma was also verified, confirming the method’s robustness toward matrix variation.A kinetic comparison between RDSDE and conventional Rotating Disk Sorptive Extraction (RDSE) revealed markedly faster extraction kinetics for RDSDE, reaching equilibrium within 20 min, whereas RDSE required substantially longer extraction times under comparable conditions. In addition to its analytical performance, the method was evaluated using AGREE, AGREEprep, BAGI, and RAPI metrics, confirming its classification as a white analytical method that balances metrological robustness, environmental sustainability, and operational practicality.Overall, the proposed RDSDE followed by HPLC-DAD methodology represents a technically innovative and environmentally responsible alternative for florfenicol determination in animal plasma, offering significant advantages for veterinary pharmacokinetic studies and residue monitoring.

BACKGROUND:A new approach based on Stir Bar Sorptive Dispersive Microextraction (SBSDME), termed Rotating Disk Sorptive Dispersive Extraction (RDSDE), was developed to confirm and quantify the kinetic advantages of sorbent-based dispersive techniques compared to their non-dispersive counterparts. Among non-dispersive techniques, Rotating Disk Sorptive Extraction (RDSE) allows for a direct comparison with its dispersive counterpart, as the sorbent phase in RDSE can be confined within the disk cavity using the exact same amount as in the dispersive mode. This comparison is not feasible in stir bar sorptive extraction. RESULTS:The advantages of RDSE combined with the dispersion of magnetic sorbent materials were explored using RDSDE technology. Magnetic activated carbon (MAC) derived from avocado seeds was used as the sorbent, with triclosan (TCS), bisphenol A (BPA), ibuprofen (IBU), and 1-hydroxy-ibuprofen (1-OH-IBU) as representative analytes. The RDSDE method was optimized for efficiency and speed. Optimal conditions were: 10 mg of MAC, 20 min extraction at pH 2, acetone as desorption solvent and 10 min desorption. These parameters provided the best analytical response with minimal time and resource use. The method was then validated, and a kinetic comparison was performed. The results demonstrated that RDSDE reaches extraction equilibrium in approximately 20 min, significantly faster than RDSE. The initial extraction velocities were between 12 times higher for BPA and 43 times higher for IBU in the dispersive mode. SIGNIFICANCE:The kinetic comparison clearly shows that RDSDE is a more efficient extraction technique due to its rapid extraction equilibrium. The dispersive mechanism plays a crucial role in accelerating analyte extraction, as evidenced by the steeper extraction profiles of RDSDE compared to RDSE. Importantly, this study presents the first direct kinetic comparison between RDSDE and conventional RDSE, highlighting the novelty of the approach. This underscores the potential of RDSDE as a faster and more efficient method for extracting target compounds from aqueous samples, offering significant advantages in analytical performance and operational efficiency.

A novel chitosan-biochar biocomposite was engineered as a synergistic and sustainable sorbent phase for the extraction of carbamazepine and its metabolites from environmental waters. The material was prepared using citric acid as a green crosslinker and glycerol as a plasticizer. Its formulation was optimized through experimental design. Compared with crosslinked chitosan and biochar, the biocomposite exhibited superior extraction performance. Mathematical modeling, together with complementary characterization analyses, corroborated this enhancement, which revealed a synergistic hybrid effect involving multi-site interactions beyond surface area contributions. Sustainability was demonstrated by the use of renewable precursors, along with a comprehensive assessment of biodegradability, biocompatibility, and toxicity of the constituents, reusability over multiple extraction-desorption cycles, and the application of analytical greenness metrics. Applied in rotating-disk sorptive extraction, the optimized methodology achieved high recoveries (86-96 %), with low relative standard deviations (<16 %), and sub-μg L-1 limits of detection, performing comparably to commercial sorbent phases and outperforming others. The method enabled the determination of the analytes in river water, confirming the potential of this material as a cost-effective, sustainable, and high-performance material for environmental monitoring.

In the realm of green analytical chemistry, there is growing interest in sorbent phases derived from natural materials like grapefruit peels as promising alternatives to commercial sorbent phases. Initially, the effectiveness of grapefruit peels in their natural state was compared to activated carbons treated with activating agents as a sorbent phase in rotating disk sorptive extraction (RDSE). The conditions for synthesizing activated carbon were optimized by adjusting the activating agent variables, proportions, and temperatures to obtain an efficient material for extracting ethylparaben (EP), propylparaben (PP), ibuprofen (Ibu), triclosan (TCS), bisphenol A (BPA), and 17-alpha-ethinylestradiol (EE2) using rotating disk sorption extraction technique from aqueous samples. The optimal conditions were determined to be activation with ZnCl2 at a 1:1.2 ratio (material: activating reagent) and carbonization at 400 degrees C (AC400(Z1.2)). Characterization revealed a hydrophilic microporous material with a large surface area and aromatic structure, confirming its potential as a sorbent phase for aqueous sample preparation. The application of AC400(Z1.2) sorbent phase in RDSE in river water confirmed its effectiveness, revealing EP, PP, Ibu, TCS, and BPA in concentrations ranging from 0.18 to 2.8 mu g L-1, with EE2 concentration below the limit of detection. Reusability studies demonstrate that this material can be reused for the simultaneous extraction of analytes in at least two consecutive extractions without requiring additional treatment between extractions. This material proves to be an economical and bio-based alternative to commercial sorbent phases. Finally, its application in RDSE was evaluated using green analytical chemistry metrics (AGREEprep and BAGI), resulting in a methodology with a low environmental impact.

A novel strategy for microextraction of emerging contaminants was developed by using cork activated carbon (CAC) as the sorbent phase. Carbonization of the natural phase increased the surface area and the porosity of the material, thus improving the extraction efficiency. Moderately polar compounds, such as ibuprofen and its metabolites, were used as model analytes in water samples. Rotating disk sorptive extraction (RDSE) together with gas chromatography‒mass spectrometry (GC‒MS) were used for extraction and determination of the analytes, respectively. The optimum conditions for the material synthesis were 600 °C, K2CO3 as the activating agent and a mass ratio of 0.8:1 (activating agent:raw material). The optimum values for the RDSE were pH 2, a sample volume of 25 mL and an extraction time of 90 min. The absolute recovery rates for ibuprofen and its metabolites ranged from 19 to 55%, and the relative standard deviations were between 3 and 13%. The proposed method was used to measure the analytes in the influent and effluent from a wastewater treatment plant in Santiago, Chile. The concentrations found for ibuprofen and its metabolites were 0.98–9.8 µg L-1 and 0.8–8.6 µg L-1 in the influent and effluent, respectively. Activation of the cork material enabled the synthesis of a sorbent phase with sorption efficiencies similar to those obtained with the commercial octadecylsilane (C18) phase and superior to that observed for styrene-divinylbenzene (S-DVB). This process is simple and cost-effective.

According to green analytical chemistry principles, the use of agricultural byproducts as sorbent phases is an interesting topic due to their lignocellulosic origin, as they are biodegradable and inexpensive. To the best of our knowledge, this is the first study in which avocado seed and avocado seed activated carbon are proposed as sustainable sorbents for solid-phase microextraction technologies, which were used to assess the proof of concept. Rotating disk sorptive extraction (RDSE) was used as a model technology and ibuprofen (Ibu) and 1-hydroxy-ibuprofen (1-OH-Ibu) as representative analytes. It was found that activated carbon (AC) prepared at 600 °C with an impregnation ratio (raw material/activating agent (ZnCl2), w/w) of 1:1.2 had better extraction efficiency than other ACs obtained at different temperatures, impregnation ratios, and activating agents (K2CO3). Characterization revealed several differences between natural avocado seed, biochar prepared at 600 °C, and selected AC since the typical functional groups of the natural starting material begin to disappear with pyrolysis and increasing the surface area and pore volume, suggesting that the main interactions between analytes and the sorbent material are pore filling and π-π stacking. By using this AC as the sorbent phase, the optimal extraction conditions in RDSE were as follows: the use of 50 mg of sorbent in the disk, 30 mL of sample volume, pH 4, 90 min of extraction time at a rotation velocity of the disk of 2000 rpm, and methanol as the elution solvent. The extracts were analyzed via gas chromatography coupled to mass spectrometry (GC–MS). The method provided limits of detection of 0.23 and 0.07 µg L−1 and recoveries of 81

The use of agricultural byproducts for the development of new sorbent phases has become increasingly popular among the scientific community of analytical chemists due to the intrinsic properties of these materials, including biodegradability, nontoxicity and biocompatibility. In the current research, peanut shells, peanut shell biochar and activated carbon were assessed as microextraction sorptive phases by using rotating disk sorptive extraction of emerging contaminants covering a range of polarities (ethyl paraben, diclofenac, triclosan, bisphenol A, and 17-alpha-ethinylestradiol) and subsequent detection by gas chromatography coupled to mass spectrometry (GC-MS). It was demonstrated that, independent of the polarity of the analyte, the extracting capacities of the activated carbon were superior to those of biochar and the untreated phase. The three sorptive phases were characterized by different techniques. SEM micrographs show the absence of pores in the untreated phase, which changes substantially after pyrolysis. The activated carbon exhibited a BET area of 516 m(2) g(-1) and a pore size and total pore volume of 2.12 nm and 0.27 cm(3) g(-1), respectively. The high porosity and some characteristic signals in the FTIR spectra suggest that the main interactions of activated carbons with analytes are pore filling and pi-pi stacking. Optimization studies showed that the optimal conditions for extraction were 10 mg of sorptive phase, pH 2, 70 min of extraction time, 15 mL of sample volume, 2000 rpm rotating velocity, and ethyl acetate as the elution solvent. The validation showed limits of detection between 0.003 and 0.729 mu g L-1, absolute recoveries ranging between 16 and 87% and relative standard deviations below 10%. A comparative study using the same extraction technology but with commercial phases demonstrated that activated carbon achieves comparable or higher extraction efficiencies for this set of analytes.

The features and nature of the sorptive phase may be the stage that determines the scope of microextraction techniques. In search of new alternatives, materials of natural origin have recently been explored to establish greener analytical strategies. Based on that search, this research proposes the use of chitosan as a sorptive phase, which was assessed in the rotating disk sorptive extraction of emerging contaminants from aqueous systems. Chitosan is a biopolymer of animal origin that is usually found in the shells of crustaceans. The main charac-teristic of this material is the presence of a high number of nitrogenous groups, which gives it high reactivity, but its main disadvantage is associated with its high swelling capacity.In this research, chitosan was crosslinked with a low concentration of glutaraldehyde to form thin films that were easily immobilized on the surface of the rotating disk. The main advantage of this modification is the considerable decrease in the swelling capacity, which prevents loss and rupture of the sorbent during high rotation of the disk. In addition, it not only improved the physical characteristics of chitosan but also increased its extraction capacity. With regard to its use as a sorptive phase, all the variables associated with the micro-extraction of the analytes were studied, and optimal variables were found to be: pH 4, 20% NaCl (salting out effect), 30-45 min as equilibrium time and elution of analytes with a mixture of methanol:ethyl acetate (1:1).Validation of the methodology for the determination of methyl triclosan and triclosan was carried out, and relative recoveries between 89 and 96% and relative standard deviations less than 14% were found. The detection limits were 0.11 and 0.20 mu g L-1, respectively. Through its application in real samples (natural and residual waters), triclosan was quantified between 0.7 and 1.3 mu g L 1. Finally, the "green" properties of the phase were evaluated, demonstrating that it is reusable for at least three cycles and biodegradable. Compared to its efficiency with a commercial phase (in this case, the styrene divinyl benzene phase), the proposed biosorbent provided a similar and even higher sorptive capacity (depending on the analyte).

The matrix of certain complex samples represents a great challenge in microextraction technology due to its ability to interfere with some step of the sample preparation procedure or in the detection itself. Normally, a suppression of the analytical signal occurs by the presence of certain components of the matrix, which tend to be coextracted with the analytes under study. Urine represents one of these complex matrices. The yellow coloration of urine comes from a main pigment known as urobilin, which can persist in all final extracts after sample treatment and has been correlated with the impossibility of correctly measuring the analytes. In the present study, we propose the determination of estrogens and their hydroxylated metabolites in urine by integration of a dispersive solid phase extraction (d-SPE) to eliminate the matrix effect with the rotating disk sorptive extraction (RDSE) of the analytes, prior to their determination by liquid chromatography/mass spectrometry.The proposed dispersive phase was primary-secondary amine (PSA), which, due to its physicochemical characteristics, allows the extraction of polar compounds (such as urobilin). Estrogens and their hydroxylated metabolites, being molecules of lower polarity, were demonstrated not to be removed by PSA and were extracted only by the styrene-divinylbenzene phase supported in the rotating disk. The amount of dispersive phase was optimized, finding that 300 mg is the best analytical response for 2 mL of urine sample. The equilibrium time for the extraction of the analytes was 60 min.Matrix-matched calibration was used for quantification, obtaining correlation coefficients greater than 0.99, limits of detection and quantification between 0.10 and 0.13 and 0.3-0.5 mu g/L, respectively, and recoveries between 72 and 130 % with precision, expressed as relative standard deviation, between 8 and 17 %. The matrix effect was reduced significantly between-24 and-48 % (without the use of d-SPE, most of the analytes were not detected). In addition, the proposed method was applied to the determination of the analytes in real urine samples of different persons. Finally, through enzymatic hydrolysis, it was possible to quantify estrogens and their hydroxylated metabolites in urine samples, both in their total form and in their naturally conjugated form.

Triclosan (TCS) is an antibacterial compound used mainly in personal care products. Its widespread use for decades has made it one of the most widely detected compounds in environmental matrices and in biological fluids. Although it has been shown to be an endocrine disruptor in rats and aquatic species, its safe use by humans is unclear. The aim of the present study was to evaluate the effects of exposure to TCS in female rats. To this end, 14 rats were divided into two groups and fed daily as follows: the control group with sesame oil and the TCS group at a dose of 50 mg/kg/day for 28 days. Any signs of toxicity in the rats were observed daily, and the weight and phase of the estrous cycle were recorded. At the end, the rats were decapitated, the serum and ovaries were collected. The levels of testosterone and progesterone in serum were determined by immunoassay and mass spectrometry. Estradiol (in serum) and kisspeptin-10 (in serum and ovary) were measured only by immunoassays. Trace elements were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The weight gain study of the rats showed a significant decrease by exposure to TCS, while the estrous cycle was not significantly affected compared to the control. The optimized methods based on mass spectrometry showed a significant decrease in the levels of progesterone and testosterone due to exposure to TCS. In addition, elements determined by ICP-MS in rat serum showed significant changes in calcium, lithium and aluminum due to TCS treatment. Finally, the kisspeptin-10 levels did not show a negative effect due to the treatment by TCS. The results suggest that medium-term exposure to TCS did not significantly alter estrous cyclicity but caused alterations in growth, sex hormone levels and some elements in the rat serum.

Novel passive samplers based on cork as a sorbent phase were implemented for the sampling and preconcentration of triclosan in water. Two sampler configurations were developed: The larger sampler (cork passive sampler, CPS) involved a Teflon casing to protect a circular laminar cork phase with a diameter of 4.5 cm, which was covered by polyethersulfone membranes. In the smaller sampler (miniaturized cork sampler, MCS), a circular piece of cork with a diameter of 0.8 cm was directly exposed in the water samples.The sampling rates were calculated through static kinetic calibration tests in the laboratory, and linearity was observed in the kinetic part of the absorption (or depletion) curve. The sampling rates were 0.47 L d −1 and 3.9 × 10−4 min−1 for CPS and MCS, respectively. The difference in these values was attributable to the substantial variation in the surface area of the exposed sorbent phase (approximately 25 times). Compared with that associated with existing passive devices, the use of cork in passive sampling devices yielded larger values of sampling rates in several cases. The samplers presented isotropy, which suggested uniform sorption and desorption capacities.The samplers were tested in the field to quantify the amount of triclosan in wastewater and river water at points near a wastewater treatment plant. The triclosan content was 19–390 and 7–271 ng L-1 for wastewater and river water, respectively. The persistence and increase in the triclosan level indicates that its use continues to be pervasive without any regulation. The proposed samplers based on cork represent an ecofriendly, efficient, low-cost and easily accessible alternative to monitor triclosan over long periods.

Phthalateacid esters (PAEs) concentration in bottled water and different factors (water pH, storage time, sunlight exposure, and temperature) that affect/control them have become hot topics during recent years. Nevertheless, quite contradictory results and disagreements on the effects of these factors have been published. In an attempt to find some consensus on this topic, a comprehensive study considering the combined effect of long storage times (longer than a year) and the water hydrochemical signature (including water pH, elemental composition and the presence/absence of dissolved CO2)was performedusing the four most commonly consumed bottled water brands on the Chilean market. Each water brand was analyzed between 10 or 14 different times, depending on the brand (in total 97 samples were studied). Following the concept ofthe hydrochemical signature typically used in hydrogeology to classify types of waters, the notion of a water phthalate fingerprint was proposed. Finally, concerning the effect of long storage times, this study demonstrates that all the trends (increase, decrease or steady) of the Total PAEs concentration are possible; and these trends are controlled by the specific hydrochemical signatureandphthalate fingerprint of the bottled water.

Ibuprofen is one of the most widely used nonsteroidal anti-inflammatory drugs due to its analgesic, anti-inflammatory and antipyretic properties, as well as its low cost and easy accessibility. A fraction of the compound and its metabolites are excreted in the urine, being eliminated in the wastewater reaching river waters in the range of ng L-1 to mu g L-1. In this context, highly sensitive and selective analytical methods are required to quantify them, including these methods a pre-concentration step. In this work, the use of a microextraction technology based on rotating-disk sorptive extraction, involving a sorptive phase of laminar cork, was implemented for the extraction of ibuprofen and 1-hydroxyibuprofen from aqueous samples and their subsequent determination by gas chromatography coupled to mass spectrometry.The optimal conditions for determination of the analytes were: 20 mL of sample volume, pH 2, 20 % w/v NaCl (to increase the ionic strength), 90 min of extraction time and 2000 rpm of rotation velocity of the disk. Recoveries of 118 and 39 % and relative standard deviations of 6 and 13 % for ibuprofen and 1-hydroxyibuprofen were obtained, respectively. The presence of both compounds in river waters (Mapocho river, Santiago of Chile) at a concentration of 2.56 to 4.08 mu g L-1 were found. The use of laminar cork as a natural sorbent phase immobilized in the rotating-disk allowed to extract the analytes from water samples through its lipophilic-hydrophilic balance that favors the interaction with the compounds under study.

A critical review of rotating-disk sorptive extraction (RDSE) is presented. This review reports the principles of RDSE regarding fundamentals, evolution and applications. RDSE is based on the extraction equilibrium between a sorptive phase and an aqueous phase that are in continuous contact and movement during extraction. The main advantage of this technique is the high mass transfer between the phases, which is achieved by the ability to reach high rotational velocities without tearing the extraction device. In addition, the great versatility of RDSE in the study of hydrophobic and hydrophilic analytes is evidenced considering the ease of immobilization of different sorptive phases in both laminar and particulate forms. RDSE is mainly coupled to chromatography; however, combination with spectroscopic techniques is also possible, allowing for measurements directly on the phase. Furthermore, automation through continuous flow systems has also been implemented in RDSE and in bioavailability studies.

Different clean-up stages were coupled to rotating-disk sorptive extraction (RDSE) of testosterone, progesterone, 17 beta-estradiol and triclosan in urine samples prior to derivatization and detection by gas chromatography-mass spectrometry (GC-MS). By using Oasis (R) HLB as the sorptive phase, extraction equilibrium was reached after 60 min at a disk rotation velocity of 2000 rpm. The factors involved in sample preparation of the urine were comprehensively studied and implemented to minimize matrix effects that were mainly produced by polar pigments in the urine. A 10-fold dilution of the sample was necessary prior to RDSE, followed by a washing step of the sorptive phase with 10% (v/v) methanolic solution and final selective desorption of the analytes with ethyl acetate. Derivatization of the analytes was also studied in detail and implemented prior to GC-MS. The reaction was optimized in terms of derivatizing agent consumption, time and temperature, achieving significant improvements in these factors. Under the optimized conditions, the matrix effects decreased almost five-fold for all analytes, and the relative recoveries were between 89 and 111% with detection limits in the range of 0.004-0.54 ng mL(-1), whereas the precision, expressed as relative standard deviation (RSD), was below 14%. Analytes were determined in real samples in the presence and absence of enzymatic hydrolysis, assessing both their free and total forms. The free triclosan concentration was only 10% of the total concentration found in the same sample after hydrolysis. Estradiol and testosterone were quantified with high sensitivity at concentrations between 0.11 and 10.45 and 0.20-21.23 ng mL(-1), respectively. Progesterone was only quantified in a urine sample from a woman during pregnancy.

An efficient method has been developed for the multiresidue and multiclass determination of 16 emerging contaminants (parabens, hormones, anti-inflammatory drugs, triclosan and bisphenol A) in water samples using rotating-disk sorptive extraction (RDSE) and gas chromatography coupled to mass spectrometry (GC-MS). Silylation of the compounds prior to GC-MS analysis was optimized using a factorial experimental design; the optimal derivatization conditions to maximize the response of the set of analytes included 70 μL of N-methyl-N-(trimethylsilyl)trifluoroacetamide at 80 °C for 35 min. RDSE was implemented using Oasis® HLB as a sorptive phase and an extraction time of 60 min.

The determination of eight phthalates in plastic bottled water was carried out using rotating disk sorptive extraction and gas chromatography-mass spectrometry.

This work reports for the first time the use of laminar cork as a sorptive phase in a microextraction technique, rotating-disk sorptive extraction (RDSE). Typical hormones (estrone, estradiol, estriol and ethinyl estradiol) were selected as analyte models and extracted from wastewater samples on laminar cork with statistically equivalent extraction efficiency to that provided by Oasis HLB. The cork characterization was performed by confocal fluorescence microscopy (CLSM), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), allowing the identification of lignin, suberin and polysaccharides (cellulose and hemicellulose) as the main components of the cork. The best conditions for extraction were as follows: rotation velocity of the disk, 2000 rpm; extraction time, 45 min; and sample volume, 20 mL. The analytical features of the developed method show that calibration curves for all analytes have R-2 values higher than 0.99. The absolute recoveries were higher than 63%, and the precision, expressed as relative standard deviation, ranged from 2 to 16%. The LOD and LOQ ranges were 3-19 and 10-62 ng L-1, respectively. The proposed method was applied to the analysis of wastewater, and the concentrations of hormones in a wastewater treatment plant in Santiago, Chile, ranged from<LOQ to 48 ng L-1. (C) 2019 Elsevier B.V. All rights reserved.