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.

A novel application of rotating disk sorptive extraction (RDSE), using a styrene-divinylbenzene (S-DVB) sorbent for the extraction of antibiotic residues in milk was developed. The analytes studied were oxytetracycline and its 4-epimer, enrofloxacin, ciprofloxacin, sulfadoxine and trimethoprim. After RDSE, the analytes were determined by performing both high-performance liquid chromatography coupled to diode array detection (HPLC-DAD) and ultrahigh-performance liquid chromatography coupled to ultraspray-electrospray-time of flight-mass spectrometry (UPLC-TOF/MS). By using HPLC-DAD, the absolute recoveries were between 85.5% and 106.4% with relative standard deviations between 3.7% and 9.9%. The obtained limits of quantification (LOQs) were lower than the respective maximum residue levels (MRLs) reported for each analyte, demonstrating that the methodology was applicable for residue depletion studies. UPLC-TOF/MS showed absolute recoveries from 88.5% to 114.1%, with RSDs between 4.3% and 15.4%. The LOQs obtained using UPLC-TOF/MS were also lower than the MRLs for each respective analyte. Compared with other analytical methods previously reported for some of the analytes, the present method is simpler and less expensive and utilizes green chemistry, all while providing comparable figures of merit.

This work presents a green and very simple approach which enables the accurate and simultaneous determination of benzo[a]pyrene, dibenz[a, h]anthracene, benz[a]anthracene, and chrysene, concerned and potentially carcinogenic heavy-polycyclic aromatic hydrocarbons (PAHs) in interfering samples. The compounds are extracted from water samples onto a device composed of a small rotating Teflon disk, with a nylon membrane attached to one of its surfaces. After extraction, the nylon membrane containing the concentrated analytes is separated from the Teflon disk, and fluorescence excitation-emission matrices are directly measured on the nylon surface, and processed by applying parallel factor analysis (PARAFAC), without the necessity of a desorption step. Under optimum conditions and for a sample volume of 25 mL, the PAHs extraction was carried out in 20 min. Detection limits based on the IUPAC recommended criterion and relative errors of prediction were in the ranges 20-100 ng L-1 and 5-7%, respectively. Thanks to the combination of the ability of nylon to strongly retain PAHs, the easy rotating disk extraction approach, and the selectivity of second-order calibration, which greatly simplifies sample treatment avoiding the use of toxic solvents, the developed method follows most green analytical chemistry principles. (C) 2014 Elsevier B.V. All rights reserved.

A novel extraction approach was developed based on rotating-disk sorptive extraction (RDSE). In this approach the rotating-disk extraction device consists of a Teflon disk, with a cavity that is loaded with a commercial sorbent phase selected according to the polarity of the analyte. To avoid leakage of the sorbent, the cavity is covered with a fiberglass filter and sealed with a Teflon ring. The proposed novel analytical RDSE technique was used in this study to determine florfenicol levels in plasma as a model analyte, or sample system, to describe the pharmacokinetics of a veterinary formulation. The sorbent used for this application was the copolymer of divinylbenzene and N-vinylpyrrolidone (Oasis HLB), which was selected because the florfenicol molecule contains both hydrophilic and lipophilic moieties. After the extraction, final determination of the analyte was performed by HPLC–DAD. Calibration plots and other analytical features were obtained after 90 min of extraction. The calibration plot was linear over the interval 0.4–16 μg mL−1 (n = 6), with R 2 = 0.9999. Recovery and repeatability were determined using a blank plasma sample spiked with 4.8 μg mL−1 florfenicol. A recovery of 91.5 %, with a relative standard deviation (RSD) of 8.8 %, was obtained when the extraction was evaluated using six different rotating-disk devices. Precision was also assessed, using the same disk (containing the same sorbent phase) for eight aliquots of the same sample. The RSD under these conditions was 10.2 %, clearly indicating that the sorptive phase could possibly be re-used. Accordingly, RDSE is a suitable sample preparation alternative to liquid–liquid extraction (LLE), solid-phase extraction (SPE), and stir-bar sorptive extraction (SBSE).

Solid-phase microextraction of hexachlorobenzene from water was implemented for the first time on a rotating disk coated with an octadecyl-bonded silica (C(18)) sorptive phase. The results indicate that the sorption performance of this phase for the model analyte selected is similar to that observed using a rotating disk containing PDMS. In both cases, equilibrium is achieved within approximately 120 min for samples volumes of 50 mL and decreases to 20-30 min when the sample volume is decreased to 10 mL. The comparable behavior observed for the sorption of HCB in both phases is consistent with a similar rate-determining step for extraction, which suggests that the overall mass transfer of analyte is not limited by internal diffusion into the phase but by diffusion into the aqueous stagnant layer. The main advantage in the use of the C(18) phase is that the elution of the analyte was achieved in 15 min compared with 45 min for PDMS because, in the case of C(18), dichloromethane can be used as the eluting solvent. The detection limit of the method was 0.08 μg L(-1) HCB for a tap-water sample. The mean recovery for the analyte was 84±2% and 85±3% for the C(18) and PDMS phases, respectively, which indicates good accuracy and precision of the method.

A novel and very simple microextraction approach for pre-concentration and direct solid phase spectrophotometric measurement has been developed for the determination of chromogenic analytes. The model analyte to assess this approach was the chromophore malachite green (MG). The analyte was extracted from water samples onto a small rotating disk made of Teflon containing a sorbent phase of polydimethylsiloxane (PDMS) on one of its surfaces. We refer to the extraction procedure as rotating disk sorptive extraction (RDSE). After extraction, the sorbent phase with the concentrated analyte was separated from the Teflon disk and used directly for MG determination by solid phase spectrophotometry at 624 nm, without the necessity of a desorption step. Chemical and extraction variables such as concentration of sodium sulfate, pH, disk rotational velocity, extraction time, and temperature were studied in order to establish the best conditions for extraction. Under optimum conditions, the extraction of MG was carried out in 18 min and 90 min, for sample volumes of 100mL or 1000 mL, respectively. The detection limit, based on three times the standard deviation of the blank phase (3σ(b)), was 1.4 μg L⁻¹ and the repeatability, expressed as relative standard deviation (RSD), for 20 μg L⁻¹ MG was 8.1%. This study also applied the method to real samples, obtaining quantitative recovery (mean recovery of 99.3%). The PDMS phases could be reused after desorbing the MG into methanol for 3h. Replacement of the PDMS film onto the disk is very easy and low cost.