Traditional Solid-phase Extraction Research Articles

Adaption and application of cell-based bioassays to whole-water samples

The increasing presence of contaminants of emerging concern in wastewater and their potential environmental risks require improved monitoring and analysis methods. Direct toxicity assessment (DTA) using bioassays can complement chemical analysis of wastewater discharge, but traditional in vivo tests have ethical considerations and are expensive, low-throughput, and limited to apical endpoints (mortality, reproduction, development, and growth). In vitro bioassays offer an alternative approach that is cheaper, faster, and more ethical, and can provide higher sensitivity for some environmentally relevant endpoints. This study explores the potential benefits of using whole water samples of wastewater and environmental surface water instead of traditional solid phase extraction (SPE) methods for in vitro bioassays testing. Whole water samples produced a stronger response in most bioassays, likely due to the loss or alteration of contaminants during SPE sample extraction. In addition, there was no notable difference in results for most bioassays after freezing whole water samples, which allows for increased flexibility in testing timelines and cost savings. These findings highlight the potential advantages of using whole water samples in DTA and provide a framework for future research in this area.

Molecularly imprinted beads based on modified cellulose hydrogel:A novel solid phase extraction filler for specific adsorption of camptothecin

Traditional solid phase extraction (SPE) suffers from a lack of specific adsorption. To overcome this problem, a combination of adsorption method and molecular imprinting technology by polydopamine modification was proposed to realize specific recognition of target compounds in SPE, which is of great significance to improve the separation efficiency of SPE. Cellulose hydrogel beads were prepared by dual cross-linking curing method and modified with polydopamine to make them hydrophilic and biocompatible. Subsequently, cellulose hydrogel-based molecularly imprinted beads (MIBs) were synthesized by surface molecular imprinting technology and used as novel column fillers in SPE to achieve efficient adsorption (34.16 mg·g−1) with specific selectivity towards camptothecin (CPT) in 120 min. The simulation and NMR analysis revealed that recognition mechanism of MIBs involved hydrogen bond interactions and Van der Waals effect. The MIBs were successful used in separating CPT from Camptotheca acuminata fruits, exhibiting impressive adsorption capacity (1.19 mg·g−1) and efficient recovery of CPT (81.54 %). Thus, an environmentally friendly column filler for SPE was developed, offering a promising avenue for utilizing cellulose-based materials in the selective separation of natural products.

Switchable metal extractant integrated miniaturized 3D-printed device: A semi-online multi-metal separation system for matrix-free ICP-MS analysis

BackgroundThis study tackles the critical challenges in metal analysis by presenting an innovative miniaturized metal extraction device prototype. This device features a functional nanocomposite (FNC) enhanced 3D-printed polylactic acid (PLA) metal extractant (FNC@3D PLA). The research is motivated by the constraints of traditional solid-phase extraction (SPE) methods, specifically their limitations in handling competitive metal ion environments and matrix interference during inductively coupled plasma mass spectrometry (ICP-MS) analysis. The designed prototype aims to overcome these challenges and enhance the extraction efficiency of diverse metals. ResultsThe FNC, designed to incorporate various functional groups critical for metal ion extraction efficiency, was meticulously engineered through the reaction of acid-treated and delaminated graphitic carbon nitride nanosheets (Thiol-gCN NSs) with 3-mercaptopropyl trimethoxysilane (MPTMS). The competitive metal ion extraction efficiency of FNC@3D PLA was demonstrated, showcasing notable limit of detection values of 3.2 ± 0.7 ng mL−1 and 8.57 ± 3.05 ng mL−1 for Cu and Ag, respectively. Furthermore, the miniaturized 3D-printed metal-preconcentration setup incorporating FNC@3D PLA exhibited favorable intraday relative standard deviation (RSD) percentage (%) values ranging from 1.23 to 8.6 for both Cu and Ag. Interday RSD % between 1.41 and 8.14 were observed under spiked real urine sample conditions. The sustainability and robustness of the proposed approach were underscored by substantial recovery % values exhibited by FNC@3D PLA, even after eight consecutive regeneration processes. SignificanceThis study significantly contributes to the advancement of analytical methodologies by providing a reliable and efficient platform for metal extraction and preconcentration in practical metal analysis applications. Developed FNC@3D PLA system demonstrates its potential to address the challenges associated with SPE in metal analysis, especially in complex sample matrices. We believe implications of this research can be extended to various fields, from environmental monitoring to clinical diagnostics, where accurate and reliable metal analysis is paramount.

Fabrication of Magnetic Molecularly Imprinted Polymers for Selective Extraction of Dibutyl Phthalates in Food Matrices.

In this study, a novel magnetic molecularly imprinted polymeric material (Fe3O4@MOF@MIP-160) with a metal-organic backbone (Fe3O4@MOF) carrier was prepared using dibutyl phthalate (DBP) as a template. The material can be used for the efficient, rapid, and selective extraction of trace amounts of phthalic acid esters (PAEs) in food and can detect them via gas chromatography-mass spectrometry (GC-MS). The synthesis conditions of the materials were optimized to prepare the Fe3O4@MOF@MIP160 with the highest adsorption performance. Transmission electron microscopy (TEM), Fourier Transform Infrared Spectra (FT-IR), Vibration Sample Magnetic (VSM), and the Brunauer-Emmett-Teller (BET) method were used to characterize the materials. Compared with Fe3O4@MOF and the magnetic non-imprinted polymeric material (Fe3O4@MOF@NIP), Fe3O4@MOF@MIP-160 possesses the advantages of easy and rapid manipulation of magnetic materials, the advantages of high specific surface area and the stability of metal-organic frameworks, and the advantages of high selectivity of molecularly imprinted polymers. Fe3O4@MOF@MIP-160 has good recognition and adsorption capacity for di-butyl phthalate (DBP) and diethylhexyl phthalate (DEHP): the adsorption capacity for DBP and DEHP is 260 mg·g-1 and 240.2 mg·g-1, and the adsorption rate is fast (reaching equilibrium in about 20 min). Additionally, Fe3O4@MOF@MIP160 could be recycled six times, making it cost-effective, easy to operate, and time-saving as compared to traditional solid-phase extraction materials. The phthalate ester content in drinking water, fruit juice, and white wine was analyzed, with recoveries ranging from 70.3% to 100.7%. This proved that Fe3O4@MOF@MIP160 was suitable for detecting and removing PAEs from food matrices.

Determination of four phenolic endocrine-disrupting chemicals in water by dispersive solid-phase extraction-ultra performance liquid chromatography-tandem mass spectrometry based on metal-organic skeleton porous carbon materials

Phenolic endocrine-disrupting chemicals (EDCs) are exogenous substances that interfere with the endocrine system and disrupt normal cell functions upon entering a living organism, leading to reproductive and developmental toxicity. Therefore, the development of a rapid and efficient analytical method for detecting phenolic EDCs in environmental waters is crucial. Owing to the low concentration of phenolic EDCs in environmental water, appropriate sample pretreatment methods are necessary to remove interferences caused by the sample matrix and enrich the target analytes before instrumental analysis. Dispersive solid-phase extraction (DSPE) has gained considerable attention as a simple and rapid sample pretreatment method for environmental-sample analysis. In this method, an adsorbent material is uniformly dispersed in a sample solution and the target analytes are extracted through processes such as vortexing. Compared with traditional solid-phase extraction (SPE), DSPE increases the contact area between the adsorbent and sample solution, reduces the required amounts of adsorbent and organic solvents, and improves the extraction efficiency. The adsorbent material plays a critical role in DSPE because it determines the extraction efficiency of the method. Metal-organic frameworks (MOFs) are porous framework materials composed of metal clusters and multifunctional organic ligands. They possess many excellent properties such as tunable pore sizes, large surface areas, and good thermal and chemical stability, rendering them ideal adsorbent materials for sample pretreatment. MOF-derived porous carbon materials obtained through high-temperature carbonization not only increase the density of MOF materials for better separation but also retain the advantages of a large surface area, highly ordered porous structure, and high porosity. In this study, a porous carbon material derived from an MOF, named as University of Oslo-66-carbon (UiO-66-C), was synthesized using a solvothermal method and applied as an adsorbent to enrich four phenolic EDCs (bisphenol A, 4-tert-octylphenol, 4-nonylphenol, and nonylphenol) in water. A method combining DSPE with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established to analyze these phenolic EDCs in water. The UiO-66-C dosage, pH of water sample, adsorption time, eluent type and volume, elution time, and ion strength were optimized. Gradient elution was performed using methanol-water as the mobile phase. The target analytes were separated on an ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm), and multiple reaction monitoring (MRM) was conducted in negative electrospray ionization mode. The method exhibited a linear correlation within the range of 0.5-100 μg/L for the four phenolic EDCs. The limits of detection (LODs) and quantification (LOQs) of the four phenolic EDCs were 0.01-0.13 μg/L and 0.03-0.42 μg/L, respectively. The precision of the method was evaluated through intra- and inter-day relative standard deviations (RSDs), with values ranging from 1.5% to 10.6% and from 6.1% to 13.2%, respectively. When applied to the detection of phenolic EDCs in tap and surface water, the spiked recoveries of the four phenolic EDCs were 77.1%-116.6%. Trace levels of 4-nonylphenol and nonylphenol were detected in surface water at levels of 1.38 and 0.26 μg/L, respectively. The proposed method exhibits good accuracy and precision; thus, it provides a new rapid, efficient, and sensitive approach for the detection of phenolic EDCs in environmental water.

3D-printed extraction devices fabricated from silica particles suspended in acrylate resin

In recent years, there has been an increasing worldwide interest in the use of alternative sample preparation methods. Digital light processing (DLP) is a 3D printing technique based on using UV light to form photo-curable resin layer upon layer, which results in a printed shape. This study explores the application of this technique for the development of novel drug extraction devices in analytical chemistry. A composite material consisting of a photocurable resin and C18-modified silica particles was employed as a sorbent device, demonstrating its effectiveness in pharmaceutical analysis. Apart from estimating optimal printing parameters, microscopic examination of the material surface, and sorbent powder to resin ratio, the extraction procedure was also optimised. Optimisation included the type and amount of sample matrix additives, desorption solvent, sorption and desorption times, and proper number of sorbent devices needed in extraction protocol. To demonstrate this method's applicability for sample analysis, the solid-phase extraction followed by gas chromatography coupled with mass spectrometry (SPE-GC–MS) method was validated for its ability to quantify benzodiazepine-type drugs. This evaluation confirmed good linearity in the concentration range of 50–1000 ng/mL, with R2 values being 0.9932 and 0.9952 for medazepam and diazepam, respectively. Validation parameters proved that the presented method is precise (with values ranging in-between 2.98 %-7.40 %), and accurate (88.81 % to 110.80 %). A negative control was also performed to investigate possible sorption properties of the resin itself, proving that the addition of C18-modified silica particles significantly increases the extraction efficiency and repeatability.The cost-effectiveness of this approach makes it particularly advantageous for single-use scenarios, eliminating the need for time-consuming sorbent-cleaning procedures, common in traditional solid-phase extraction techniques. Future optimisation opportunities include refining sorbent size, shape, and geometry to achieve lower limits of quantification. As a result of these findings, 3D-printed extraction devices can serve as a viable alternative to commercially available SPE or solid-phase microextraction (SPME) protocols for studying new sample preparation approaches.

Analysis of 14 β-agonists in pork using an automated wooden tip-based solid-phase microextraction device and ultra-high-performance liquid chromatography-tandem mass spectrometry.

This study introduces a cost-effective, automated ultra-high-performance liquid chromatography-tandem mass spectrometry method for the detection of 14 β-agonists in pork using a novel solid-phase microextraction probe composed of polyacrylonitrile and molecularly imprinted polymer. Integrated into an automated extraction device, the probe optimizes extraction prior to analysis while reducing expenses and time compared to traditional solid-phase extraction procedures. The method validation followed the Chinese National Standard (GB/T 27404-2008) and examined limits of detection, limits of quantification, matrix effects, linearity, intraday, and interday precision. Average recovery rates ranged from 71.6% to 82.2%, with relative standard deviations less than 15%. Limits of detection and limits of quantification ranged from 0.09 to 0.39 and 0.27 to 0.99μg/kg, respectively. The new method identified positive samples more accurately than the current National Standard GB/T 31658.22-2022 and demonstrated its potential for routine assessment and regulatory compliance in the detection of β-agonists in pork.

Automated magnetic-bead-assisted sequential extraction technology for simultaneous detection of Aβ1-42 and Aβ1-40 in cerebrospinal fluid: An advance toward fully automated liquid chromatography-tandem mass spectrometry method

Traditional solid-phase extraction (SPE) LC–MS/MS is limited by high costs, turnaround times, and procedural complexity, which limited the usage in clinical practice. This study aimed to establish a robust UPLC–MS/MS method with automated magnetic-bead-assisted sequential extraction (MBASE) technology to simultaneously measure Aβ1-42 and Aβ1-40 in cerebrospinal fluid (CSF). A Waters TQ-XS triple quadrupole mass spectrometer and Acquity UPLC Protein BEH C4 column were used. The targeted analytes were extracted and concentrated using the automated MBASE technology with chemically modified magnetic MCX beads. Analytical performance was verified referring to the CLSI C62-A and EP-15-A3 guidelines. A total of 68 CSF samples were collected and analyzed using the MBASE UPLC–MS/MS method, traditional SPE UPLC–MS/MS method, and Lumipulse G fully automated chemiluminescence detection system, and method comparison analysis is conducted. The MBASE UHPLC–MS/MS method showed an analytical performance equivalent to that of traditional SPE technology, with a higher sample throughput and smaller amount of materials ($34.98 vs. $493.96) and labor cost (101 min vs. 140 min) for 96 samples. The limit of quantification (LOQ) of Aβ1-42 and Aβ1-40 was 0.10 ng/mL and 0.05 ng/mL; recovery was 88.35–107.07 % and 95.72–96.60 %; and total imprecision was 3.69–6.83 % and 3.02–3.61 %, respectively. The measurements were faithfully reproduced within the allowable levels of uncertainty using certified reference materials. The correlations between this MBASE UPLC–MS/MS method, the SPE UPLC–MS/MS method, and Lumipulse G fully automated biochemical analysis method are all deemed good (r = 0.869–0.936), and the MBASE- and SPE-UPLC–MS/MS methods showed comparable measurements. To our knowledge, our study firstly verified the robust performance of the MBASE UPLC–MS/MS method to simultaneously determine Aβ1-42 and Aβ1-40 in CSF. With further introduce of automation, the assay with high accuracy and low material and labor costs will become a promising clinical technology.

Aqueous two-phase systems coupled with chemometrics-enhanced HPLC-DAD for simultaneous extraction and determination of flavonoids in honey.

In this study, an accurate, rapid, green, and environment friendly method for the extraction and quantitative analysis of flavonoids in honey was established by using the aqueous two-phase extraction combined with the chemometrics-assisted HPLC-DAD. The first purpose of this study was to extract seven flavonoids in five different types of honey using alcohol/salt aqueous two-phase system (ATPS). The system with 2.82mL sodium citrate (30%), 1.58mL water, and 3.10mL isopropanol, showed the highest flavonoids extraction yields in the top phase (87.66-101.50%). Additionally, the three-way array of honey samples based on HPLC-DAD was decomposed mathematically by the alternating trilinear decomposition (ATLD) algorithm to obtain reasonable chromatograms, spectra, and concentration profiles for each analyte. Compared with the traditional solid-phase extraction method, the ATPS-ATLD-based method showed satisfactory spiked recoveries, lower limit of detection, and higher sensitivity, further verifying its accuracy and stability.

A rapid LC-MS/MS method for multi-class identification and quantification of cyanotoxins

Cyanobacteria can form harmful blooms in specific environmental conditions due to certain species producing toxic metabolites known as cyanotoxins. These toxins pose significant risks to public health and the environment, making it critical to identify and quantify them in food and water sources to avoid contamination. However, current screening methods only focus on a single class of cyanotoxins, limiting their effectiveness. Thus, fast and sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed to analyze eighteen cyanotoxins simultaneously. A simplified extraction procedure using lyophilized samples of cyanobacterial biomass was also used, eliminating the need for traditional solid-phase extraction methods. This method uses multiple reaction monitoring and allows accurate determination and quantification of eighteen cyanotoxins, including anatoxin-a, homoanatoxin-a, cylindrospermopsin, deoxy-cylindrospermopsin, nodularin, guanitoxin, seven microcystins (RR, [D-Asp3] RR, LA, LR, LY, LW, and YR), and five saxitoxins (gonyautoxins - GTX-1&4, GTX-2&3, GTX-5), decarbamoylgonyautoxin (dcGTX-2&3), and N-Sulfocarbamoylgonyautoxin (C1&C2), all in a short acquisition time of 8 min. Therefore, this method provides a simple and efficient approach to identify and quantify harmful compounds produced by cyanobacteria. Hence, this represents the first method to detecting guanitoxin among cyanotoxins. By expanding the range of toxins analyzed, this method can help ensure high-quality food and drinking water and protect recreational users from exposure to cyanotoxins.

Matrix Solid-Phase Extraction of Nine Pesticide Residues from Vegetables Based on Mesoporous Carbon via an Alternative Sample Preparation Approach

In this work, an n-octadecylamine functionalized mesoporous carbon nanocomposite (ODA-MPC) was synthesized, and its novel application was demonstrated by utilizing it as a sorbent in matrix solid-phase dispersion (MSPD) of nine pesticide residues identified by gas chromatography-mass spectrometer. Here, the protection of the sorbent by the mesoporous fiber membrane enabled it to process complex aqueous matrices and made it advantageous to be used in MSPD. The results confirmed the excellent ability of ODA-MPC to remove matrix interferences and reduce matrix effects compared to the traditional solid phase extraction. In particular, the recoveries were 85.0–95.8% (n = 3) with relative standard deviations less than 5%. Additionally, nine pesticide residues in vegetables and fruit were satisfactorily extracted and detected.

Preparation of magnetic molecularly imprinted polymers for selective extraction of xylazine in milk

SummaryMagnetic molecularly imprinted polymers (MMIPs) were prepared by surface precipitation polymerisation, which used xylazine as its template molecule and Fe3O4 as its support. The characterisation analysis and adsorption experiments of MMIPs were carried out. At the same time, promethazine, chlorpromazine, trifluoperazine, acepromazine and perphenazine were selected as structural analogues for selective experiments. The results showed MMIPs were successfully prepared with small particle size, excellent magnetic and thermal stability, high adsorption capacity and selectivity for xylazine. The maximum adsorption capacity of MMIPs for xylazine was 4.2017 mg g−1, and the adsorption reached binding equilibrium within 30 min. The magnetic solid phase extraction (MSPE) based on MMIPs and traditional solid phase extraction (SPE) based on SPE column for xylazine in milk samples were compared and xylazine was analysed by HPLC. Although the difference between the two SPE methods was not significant, the MSPE method procedure took only about 35 min, which was faster than the traditional SPE method (>100 min), and the MSPE method had lower LOD (2.62 ng mL−1). MSPE has the advantages of simple operation, short extraction time, low cost and friendly to the environment, it has good application potential in the detection of xylazine in milk samples.

Dispersive solid-phase extraction facilitated by newly developed, fully 3D-printed device

Dispersive solid-phase extraction (DSPE) is considered a beneficial sample preparation in comparison with traditional solid-phase extraction (SPE), mostly due to its simplicity and high recoveries. In a typical procedure, the extract has to be manually aspirated from a vessel containing a centrifuged pellet of sorbent particles. This step can lead to contamination of the chromatographic system and can cause loss of the analyte. In this paper, we propose a new design of a set of simple vessels manufactured by 3D printing that help to overcome the main drawbacks of a conventional DSPE protocol. We show that a complete analytical device can be designed, improved, manufactured, and applied within one laboratory at a low cost. The usefulness of the developed sample preparation device is demonstrated in an example of imipramine and carbamazepine extraction and compared with the performance of the conventional protocol without 3D printed parts.

Novel Magnetic-Bead-Assisted Sequential Extraction Method for Liquid Chromatography-Mass Spectrometry (MS)/MS of Components with Diverse Properties: Gastrin Determination as a Case Study

Sample preparation is the rate-limiting step in liquid chromatography-mass spectrometry (LC-MS)/MS-based clinical analysis when target analytes possess significantly different properties. Repeated solid-phase extraction (SPE) processes are typically required, resulting in low throughput and excessive consumption of labor, materials, and samples. In this study, we developed and validated a feasible and productive method to enrich target analytes with different properties during a single operation, while sufficiently removing matrix interferences to meet LC-MS/MS requirements. Gastrin determination was selected as the subject of this study. An automated magnetic-bead-assisted sequential extraction (MBASE) workflow was developed to simultaneously isolate nonsulfated gastrin-17 (G17ns), sulfated gastrin-17 (G17s), nonsulfated gastrin-34 (G34ns), and sulfated gastrin-34 (G34s) from human serum. It performs two different ion-exchange-based magnetic-bead extraction steps on one sample aliquot to produce one combined extract for LC-MS/MS analysis. When compared with the traditional SPE process, the MBASE workflow saves over 75% time and labor expenses as well as over 90% material cost, while providing even higher extraction efficiency. The MBASE LC-MS/MS method was validated as accurate and robust. Clinical sample test results demonstrated that the conventional chemiluminescence immunoassay method significantly under-estimated total gastrins in human serum, and the MBASE LC-MS/MS method could serve as an ideal tool to provide a comprehensive and accurate gastrin profile.

A Fast Method for the Simultaneous Analysis of 26 Beta-Agonists in Swine Muscle with a Multi-Functional Filter by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

A rapid and simplified sample preparation method was developed for the simultaneous determination of 26 beta-agonists in swine muscle using a multi-functional filter (MFF) based on quick, easy, cheap, effective, rugged, and safe methods (QuEChERS). MFF integrated the cleanup and filter procedures, thereby significantly improving the efficiency of sample preparation compared with traditional solid-phase extraction. The sample was processed via enzymatic hydrolysis, purified with the optimized MFF containing 150 mg magnesium sulfate, 50 mg PSA, and 50 mg C18, and then analyzed using ultra-high performance liquid chromatography-tandem mass spectrometry. All procedures can be completed in 6.5 h. Good linearity (R2 > 0.99) was detected in all analytes. The recoveries ranged from 71.2% to 118.6%, with relative standard deviations (RSDs) of less than 18.37% in all spiked concentrations. The limits of detection (LOD) and the limits of quantitation (LOQ) were 0.01–0.10 and 0.10–0.50 μg/kg, respectively. The decision limit (CCα) and detection capacity (CCβ) values fluctuated in the range of 3.44–25.71 and 6.38–51.21 μg/kg, respectively. This method is a good alternative for detecting beta-agonist residues in swine muscle and can be successfully applied to the national risk monitoring of agro-product quality and safety in China.

An automated magnetic bead extraction method for measuring plasma metanephrines and 3-methoxytyramine using liquid chromatography tandem mass spectrometry.

Liquid chromatography tandem mass spectrometry (LC-MS/MS) is used routinely in clinical diagnostics; however, automating the sample pretreatment is challenging. We established and evaluated an automated method based on the magnetic bead extraction principle (MBE) to measure normetanephrine (NMN), metanephrine (MN), and 3-methoxytyramine (3-MT). The target analytes were extracted, purified, and concentrated using different solvents and chemical bond-modified magnetic beads transferred via a magnetic bar. The linearity, recovery, matrix effect, and precision of MBEwere evaluated thoroughly, and compared with traditional solid-phase extraction (SPE) using 131 plasma samples. The chromatography peaks of metanephrines and 3-MT, extracted via MBE, are symmetrical, without interfering peaks. The linearity was excellent with correlation coefficient (r) > 0.99. The MBE exhibited good reproducibility with within-run coefficient variations (CVs) of 1.96-2.00%, 4.06-5.75%, and 3.89-4.90% for MN, NMN, and 3-MT, respectively. The total CVs for MN, NMN, and 3-MT were 1.96-2.80%, 5.12-5.75%, and 5.44-6.27%, respectively. The relative recoveries for MN, NMN, and 3-MT varied between 93.5 and 107.4%, whereas their biases were all within 10%. The results for MN, NMN, and 3-MT extracted via MBE compared with SPE exhibited excellent correlation, with r > 0.99; the mean bias% for MN, NMN, and 3-MT were small (-2.9%, -3.2%, and -3.2%, respectively). In conclusion, the automated MBE method for measuring plasma metanephrines and 3-MT can be applied in future routine clinical diagnostics, and the MBE principle may indicate a new era for LC-MS/MS in clinical application.

Determination of Nitrofuran Metabolites in Complex Food Matrices Using a Rough, Cheap, Easy-Made Wooden-Tip-Based Solid-Phase Microextraction Probe and LC-MS/MS

In this study, a rough, cheap, easy-made wooden-tip-based solid-phase microextraction (SPME) probe was first developed for simultaneous determination of 4 nitrofuran metabolite derivatives in complex food matrices via LC-MS/MS. A simple dip-coating method was used to coat wooden tips with biocompatible polyacrylonitrile (PAN) and N-vinylpyrrolidone-co-divinylbenzene, also known as HLB particles, which served as the extractive substrate in the proposed device. Compared with the traditional solid-phase extraction (SPE) method, the proposed device shortens sample clean-up time, reduces solvent consumption, and decreases testing costs. In addition, the main parameters affecting the SPME procedure efficiency were investigated in detail and the optimal conditions were found. The method was validated using three different food matrixes (pork, croaker, and honey) by spiking with the four metabolites at 0.5, 1.0, and 5.0 μg/kg, as well as their internal standards. The average recovery of all nitrofuran metabolite derivatives ranges from 97.4–109.5% (pork), 87.5–112.7% (croaker), and 98.6–109.0% (honey). Relative standard deviations were all <10% for intraday and interday precision. The values of limit of detection and limit of quantification were, respectively, ranging from 0.011 to 0.123 and 0.033 to 0.369 μg/kg (pork), 0.009 to 0.112 and 0.027 to 0.339 μg/kg (croaker), and 0.010 to 0.131 and 0.030 to 0.293 μg/kg (honey). The presented method was applied to the analysis of real positive samples.

Preparation of a Novel Resin Based Covalent Framework Material and Its Application in the Determination of Phenolic Endocrine Disruptors in Beverages by SPE-HPLC.

A new type of economical covalent organic framework material(COF), namely resin based covalent organic framework material, was prepared by combining resin and covalent organic framework material by hydrothermal synthesis, which was based on the preparation of traditional COF material(TpBD COF). The properties of the material and covalent organic framework material were compared in the way of characterization, and the possible reaction mechanism was analyzed. The solid phase extraction separation (SPE) ability of this material for four kinds of phenolic endocrine disrupting compounds (bisphenol F, bisphenol A, octylphenol and nonylphenol) in beverage samples was investigated. The results showed that the prepared COF materials had abundant internal channels, ordered structure, large specific surface area (TpBD COF: 814.6 m2/g and resin based COF: 623.9 m2/g) and good thermal stability (pyrolysis temperature was 443 °C and 437 °C, respectively). Solid phase extraction experiments demonstrated that the two COF materials as adsorbent of solid phase extraction column had ideal adsorption separation effect and good anti-interference ability, and had strong anti-interference ability. The SPE effect was superior to the traditional solid phase extraction column. The precision RSD of this method was less than 3%. This SPE method had high recovery and could be reused (carbonated beverage: 98.18–102.18% and beverage: 98.52–101.79%), In addition, the recovery of the material did not change significantly in the 50 cycles of solid phase extraction, indicating that the material had good stability and could be reused, which could meet the requirements for the detection and analysis of trace pollutants in environmental samples. The resin based COF material prepared in this study could reduce the cost of monomer uses and provide a possibility for its industrial production. At the same time, as an efficient SPE adsorbent, it also provided a new research scheme for the enrichment of trace phenolic endocrine disruptors in beverage samples.

Determination of tetracycline and fluoroquinolone residues in fish by polydopamine nanofiber mat based solid phase extraction combined with ultra performance liquid chromatography-tandem mass spectrometry

制备聚多巴胺(PDA)修饰的聚苯乙烯纳米纤维膜(PS NFsM)作为固相萃取吸附介质,可快速提取淡水鱼中3种四环素类(四环素、金霉素、土霉素)和3种氟喹诺酮类(恩诺沙星、环丙沙星、诺氟沙星)药物残留,结合超高效液相色谱-串联质谱(UPLC-MS/MS),建立了药物残留检测的新方法。利用静电纺丝法制备了聚苯乙烯纳米纤维膜,将其作为模板,通过自聚合作用,进行聚多巴胺功能化修饰,得到PDA-PS NFsM材料。对制得的PS NFsM和PDA-PS NFsM材料进行傅里叶红外光谱和场发射扫描电镜表征,证明PDA的成功修饰,修饰后的纳米纤维表面粗糙,呈现核-壳形貌,纤维内部为蜂窝状多孔结构。以空白加标样品的回收率为指标,对PDA-PS NFsM材料的用量、离子强度、样品溶液的流速、洗脱液和突破体积等影响SPE的因素进行考察及条件优化,确定了最佳的SPE条件。该方法对6种目标物的检出限为0.3~1.5 μg/kg,定量限为1.0~5.0 μg/kg,低于国家标准和行业标准;在各目标物的线性范围内均有良好的线性关系,决定系数(R2)大于0.999,方法的回收率为94.37%~102.82%,日间和日内的相对标准偏差(RSD)均小于10%,与国家标准和行业标准相当。通过固相萃取前后的基质效应对比,表明PDA-PS NFsM具有优秀的净化能力。最后,通过实际样品分析验证了方法的实际应用可行性。该文建立的基于PDA-PS NFsM材料的SPE方法是一种高效环保的方法,可为淡水鱼中药物残留的常规监测提供技术支持。

3D printed structure coated with C18 particles in an online flow system coupled to HPLC-DAD for the determination of flavonoids in citrus external peel

A 3D printed disc coated with C18 resin was developed and used in a flow system coupled to high-performance liquid chromatography (HPLC) with diode array detection (DAD), for the extraction, separation and quantification of six flavonoids: naringin, naringenin, hesperidin, hesperetin, diosmetin and tangeretin in the citrus external peel. The developed method is based on the automatic loading of 16 mL of sample into an extraction tank with a 3D printed C18 disc (8 mm id × 5.5 mm height) with 39.01 mg of immobilized C18. Then, the matrix is cleaned-up in 15 s and the analytes are eluted in 10 s with 0.3 mL of acetonitrile (twice). The extract is directly injected into the HPLC (0.01 mL). A monolithic C18 column is employed to perform the separation using a mixture of acetonitrile and acidified water (pH = 2.5) as a mobile phase in gradient mode. The total procedure time is 28 min. Limits of detection, quantification and relative standard deviations range between 5.86 × 10−2 and 4.69 × 10−2 µg/mL, 2.34 × 10−2 and 1.88 × 10−1 µg/mL, and 3.29–4.49%, respectively. The coupling between the flow-based extraction system and the HPLC provides a fully automated method for the extraction and determination of the studied flavonoids reducing the consumption of time and solvents, and improving the analysis sensitivity and throughput. The developed 3D printed device notably eliminates the drawback of the generated backpressure in flow systems using traditional solid-phase extraction columns. Thus, a robust and effective automated solid-phase extraction method has been developed, optimized, and successfully applied for the determination of six flavonoids in 8 citrus external peel samples.