Automated multisyringe stir bar sorptive extraction using robust montmorillonite/epoxy-coated stir bars

Advancements in Clay Materials for Trace Level Determination and Remediation of Phenols from Wastewater: A Review

The wide spread of phenols and their toxicity in the environment pose a severe threat to the existence and sustainability of living organisms. Rapid detection of these pollutants in wastewaters has attracted the attention of researchers from various fields of environmental science and engineering. Discoveries regarding materials and method developments are deemed necessary for the effective detection and remediation of wastewater. Although various advanced materials such as organic and inorganic materials have been developed, secondary pollution due to material leaching has become a major concern. Therefore, a natural-based material is preferable. Clay is one of the potential natural-based sorbents for the detection and remediation of phenols. It has a high porosity and polarity, good mechanical strength, moisture resistance, chemical and thermal stability, and cation exchange capacity, which will benefit the detection and adsorptive removal of phenols. Several attempts have been made to improve the capabilities of natural clay as sorbent. This manuscript will discuss the potential of clays as sorbents for the remediation of phenols. The activation, modification, and application of clays have been discussed. The achievements, challenges, and concluding remarks were provided.

Application of a new adhesive elastomeric coating and hydrophilic-lipophilic-balanced sorbent for modified stir-bar sorptive extraction

A new polyurethane adhesive was evaluated to fix a hydrophilic-lipophilic-balanced sorbent and to produce modified stir-bars. It presented high mechanical and chemical resistance, indicating that it is an adequate adhesive. The homemade bars were employed to determine bisphenol A, diclofenac, ibuprofen and triclosan in aqueous medium. Satisfactory figures of merit were observed, with LOD between 0.06 and 0.30 ng mL-1 and enrichment factors between 133 and 195 times, using an extraction time of 2 h. The stir-bars were employed to determine the four analytes in water samples, presenting recovery results from 53 to 135% and RSD between 0.7 and 20%. In general, the results observed here indicated that the adhesive is an appropriate alternative material to fix HLB particles, and could probably be applied to other sorbents.

Stir bar sorptive extraction and its application

Recent progress of stir bar sorptive extraction (SBSE) in the past six years is reviewed. The preparation methods including electrodeposition, self-assembly, solvent exchange, physical magnetic adsorption and electrostatic spinning, for the coated stir bar are summarized and compared, specifically for a specific material for coatings fabrication, e.g., carbon-based materials and metal organic frameworks. The emerging materials (e.g., graphene, graphene oxide, carbon nanotubes, monolith, metal-organic frameworks and porous organic polymers) applied for coated stir bar fabrication are one of the focus of this review, along with their respective advantages in extraction process and application in trace analysis. The development and application of extraction apparatus of SBSE are also involved. Based on these information, the development status and prospects of SBSE as an efficient sample pretreatment technique in real sample analysis are discussed.

A banana peel/silicon glue coated stir bar for extraction of aspirin, diclofenac, ibuprofen and mefenamic acid followed by high performance liquid chromatography-UV detection

In the current study, a green, cost-effective, and bio-degradable additive was used for the preparation of a highly efficient sorbent based on silicon glue. Here, a banana peel was pretreated and mixed with silicon glue. It was proved that the prepared banana peel-silicon glue bar is a reliable sorbent for stir bar sorptive extraction of nonsteroidal anti-inflammatory drugs (NSAIDs) including aspirin, diclofenac, ibuprofen and mefenamic acid in human urine and plasma. Compared to the lab-made sorbents, the prepared sorbent showed high extraction performance, high stability, and satisfactory reproducibility and involved easy preparation. In order to optimize the effective factors, different parameters such as (stirring rate, pH, extraction time, desorption time and elution solvent volume) were optimized using response surface methodology (RSM) through applying Central-Composite Design (CCD). Under the optimum conditions, the linear dynamic ranges of the target analytes were investigated in the range of 0.2-200 μg L^-1 with r² higher than 0.9929. Limits of detection (LODs) and limits of quantification (LOQs) of analytes were in the ranges of 0.04-0.5 and 0.15-1.65, respectively. The reproducibility of the method was also investigated by calculating the relative standard deviation. The RSD was measured to be lower than 4.9%. Bar-to-bar reproducibility at a 100 μg L^-1 concentration level was also evaluated to be lower than 5.3% (n = 3). Also, each prepared film can be used up to 64 times without any reduction in extraction performance. Finally, the method was successfully applied for the determination of selected drugs in different biological fluids including urine and plasma samples. The calculated relative recovery in real sample analysis was higher than 90%.

Cork sheet as a sorptive phase to extract hormones from water by rotating-disk sorptive extraction (RDSE)

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 R² 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.

Epoxy resin as a new alternative sorbent phase for stir bar sorptive extraction for the determination of triclosan and methyl-triclosan

The main objective of this study is to propose a new sorbent phase based on a commercial epoxy resin, for use as an alternative sorbent in the stir bar sorptive extraction (SBSE) technique. The analytes triclosan (TCS) and methyl-triclosan (MTCS) were selected in order to demonstrate the application of the bars, using some water samples as matrices. The extraction conditions of sample volume, stirring time, pH, temperature and ionic strength were evaluated, and for the back extraction, the bars were sonicated using 1.00 mL of acetonitrile for 10 min. The technique of liquid chromatography using a diode array detector was employed for the quantitation. Analytical curves of between 2.50 and 50.0 μg L^-1 with r² of 0.9894 (TCS) and 0.9933 (MTCS), and limit of detection (LOD) values of 0.6 μg L^-1 (TCS) and 2.0 μg L^-1 (MTCS) were observed. Recovery values between 100.4% and 121.6% were verified for ultrapure water and between 50.3% and 93.8% for wastewater samples, thereby suggesting the possibility of employing the bars for quantitation of TCS and MTCS in aqueous samples. This is the first time that this resin has been applied without the need for the adhesion of any additional sorbent phase, thereby providing a simple and low-cost method. Another feature is that only eight bars were employed in the entire work, and each bar was used approximately 40 times with the same performance without memory effects.

3D printed device including disk-based solid-phase extraction for the automated speciation of iron using the multisyringe flow injection analysis technique

The development of advanced manufacturing techniques is crucial for the design of novel analytical tools with unprecedented features. Advanced manufacturing, also known as 3D printing, has been explored for the first time to fabricate modular devices with integrated features for disk-based automated solid-phase extraction (SPE). A modular device integrating analyte oxidation, disk-based SPE and analyte complexation has been fabricated using stereolithographic 3D printing. The 3D printed device is directly connected to flow-based analytical instrumentation, replacing typical flow networks based on discrete elements. As proof of concept, the 3D printed device was implemented in a multisyringe flow injection analysis (MSFIA) system, and applied to the fully automated speciation, SPE and spectrophotometric quantification of Fe in water samples. The obtained limit of detection for total Fe determination was 7ng, with a dynamic linear range from 22ng to 2400ng Fe (3mL sample). An intra-day RSD of 4% (n = 12) and an inter-day RSD of 4.3% (n = 5, 3mL sample, different day with a different disk), were obtained. Incorporation of integrated 3D printed devices with automated flow-based techniques showed improved sensitivity (85% increase on the measured peak height for the determination of total Fe) in comparison with analogous flow manifolds built from conventional tubing and connectors. Our work represents a step forward towards the improved reproducibility in the fabrication of manifolds for flow-based automated methods of analysis, which is especially relevant in the implementation of interlaboratory analysis.

Preparation of magnetic mesoporous carbon from polystyrene-grafted magnetic nanoparticles for rapid extraction of chlorophenols from water samples

A magnetic mesoporous carbon material (Fe₃O₄@C) was fabricated by carbonizing polystyrene grafted polydopamine-coated magnetic nanoparticles.