Multiplex Detection of Single Nucleotide Polymorphisms by Liquid Chromatography for Nonsmall Cell Lung Cancer Staging.

In this work, an integrated strategy with excellent accuracy and high throughput is proposed for the precise indication of single nucleotide polymorphism (SNP) in nonsmall cell lung cancer diseases. Two types of point mutations (L858R and T790M) and the corresponding wild types could be identified together in a single high-performance liquid chromatographic run. Signal amplification was achieved through a series of enzyme ligation, primer extension, and enzyme cleavage strategies, and a large number of DNA probes with different fluorescence signals were finally generated. The factors affecting the spatiotemporal separation efficiency of four DNA probes were systematically investigated. The limits of detection of wild types (WTs) or mutant types (MTs) abbreviated as L858R-MT, L858R-WT, T790M-MT, and T790M-WT were 26, 24, 19, and 22 aM, respectively. In addition, the levels of mutant types and wild types in the serum of 40 nonsmall cell lung cancer patients at different stages were detected using the method, and the correlation between the mutation ratios and cancer stages was preliminarily verified. The proposed highly selective and sensitive method may serve as an alternative approach for early diagnosis and staging of nonsmall cell lung cancer.

Changes in Concentrations of Polyfluoroalkyl Substances in Human Milk Over Lactation Time and Effects of Maternal Exposure via Analysis of Matched Samples.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are potentially related to many adverse health outcomes and could be transferred from maternal blood to human milk, which is an important exposure source for infants during a long-term period. In this study, the maternal blood of 76 women after delivery and their matched human milk samples obtained at 0.5, 1, and 3 months were analyzed by solid-phase extraction method with metal-organic framework/polymer hybrid nanofibers as the sorbents and ultrahigh-performance liquid chromatography-negative electrospray ionization mass spectrometric for quantitative analysis of 31 PFAS. The perfluorooctanoic acid, perfluorooctane sulfonate, and N-methyl perfluorooctane sulfonamido acetic acid (N-MeFOSAA) contributed to more than approximately 50% of the total PFAS concentrations in blood and human milk, while N-MeFOSAA (median: 0.274 ng/mL) was the highest PFAS in human milk at 3 months. The transfer efficiencies for PFAS from maternal blood to human milk at 0.5 months were generally lower, with medians ranging from 0.20% to 16.9%. The number of PFAS species detected in human milk increased as the lactation time went on from 0.5 to 3 months, and the concentrations of 10 PFAS displayed an increasing trend as the prolongation of lactation time (p < 0.05).

Spatial Confinement of Single-Drop System to Enhance Aggregation-Induced Emission for Detection of MicroRNAs.

Due to high incidence, poor prognosis, and easy transformation into pancreatic cancer (PC) with high mortality, early diagnosis and prevention of acute pancreatitis (AP) have become significant research focuses. In this work, we proposed a magnetic single-drop microextraction (SDME) system with spatial confinement to enhance the aggregation-induced emission (AIE) effect for simultaneous fluorescence detection of miRNA-155 (associated with AP) and miRNA-196a (associated with PC). The target miRNAs were selectively recognized by the hairpin probe and triggered the DNA amplification reaction; then, the DNA strands with two independent probes of G-quadruplex/TAIN and Cy5 were constructed on the surfaces of the magnetic beads. The SDME process, in which a drop containing the fluorescence probes was formed at the tip of the magnetic microextraction rod rapidly within 10 s, was performed by magnetic extraction. In this way, G-quadruplex/TAIN was enriched owing to the spatial confinement of the single-drop system, and the fluorescence signal given off (by G-quadruplex/TAIN) was highly enhanced (AIE effect). This was detected directly by fluorescence spectrophotometry. The approach achieved low limits of detection of 2.1 aM for miRNA-196a and 8.1 aM for miRNA-155 and wide linear ranges from 10 aM to 10 nM for miRNA-196a and from 25 aM to 10 nM for miRNA-155. This novel method was applied to the fluorescence detection of miRNAs in human serum samples. High relative recoveries from 95.6% to 104.8% were obtained.

Self-Generation of Distinguishable Fluorescent Probes via a One-Pot Process for Multiple MicroRNA Detection by Liquid Chromatography.

To address the challenge of signal production and separation for multiple microRNA (miRNA) detection, in this work, a "one-pot" process to self-generate distinguishable fluorescent probes was developed. Based on a long and short probe amplification strategy, the generated G-quadruplex fluorescent dye-free probes can be separated and detected by a high-performance liquid chromatography-fluorescence platform. The free hairpin probes enriched in guanine with different lengths and base sequences were designed and could be opened by the target miRNAs (miRNA-10b, miRNA-21, and miRNA-210). Cleaved G-quadruplex probes with fluorescent signal could be generated in a one-pot process after a duplex-specific nuclease-based cleavage, and the detection of multiple miRNAs could be realized in one run. No solid nanomaterials were applied in the assay, which avoided the blocking of the column. Moreover, without modification of expensive fluorescein, the experimental cost was greatly reduced. The one-pot reaction process also eliminated tedious preparation steps and suggested feasibility of automation. The limits of detection of miRNA-10b, miRNA-21, and miRNA-210 were 2.19, 2.20, and 2.75 fM, respectively. Notably, this method was successfully applied to multiplex detection of miRNAs in serum samples from breast cancer patients within 30 min.

Per- and Polyfluoroalkyl Substances in Personal Hygiene Products: The Implications for Human Exposure and Emission to the Environment.

Per- and polyfluoroalkyl substances (PFAS) have been related to reproductive toxicity in humans, but their occurrence in some specific personal hygiene products, i.e., sanitary pads, panty liners, tampons, paper diapers, menstrual cups, and bactericidal liquids, has not been extensively studied. This work investigated 31 representative PFAS in six categories of such personal hygiene products (n = 91). Perfluorinated carboxylic acids were the primary PFAS found in the samples, accounting for over 85% of the total concentrations of PFAS. Paper diapers contained the highest sum of PFAS concentrations (64.6 ng/g) followed by sanitary pads (52.3 ng/g) and menstrual cups (21.1 ng/g). The estimated exposure doses of perfluorooctanoic acid through dermal absorption from the use of menstrual cups and paper diapers for infants (adults) were 0.77 and 2.1 (1.2) ng/kg-bw/day, which contributed more than normal dust ingestion. The estimated emission of paper diapers and sanitary pads into the environment was 2.58 and 322 kg/year with an assumed leaching rate of 100%. The potential exposure of PFAS through the use of personal hygiene products observed in this work suggests a previously unreported exposure pathway of these chemicals to humans.

Can Direct-Immersion Aqueous-Aqueous Microextraction Be Achieved When Using a Single-Drop System?

For the analysis of biological analytes in complex matrices, it is difficult to achieve extraction of analytes and enrichment in an aqueous-aqueous single-drop microextraction system. In this study, we proposed a pH-dependent polydopamine (PDA)-coated vesicle/Fe3O4 magnetic aqueous-aqueous in a single-drop microreactor (SDMR) for the direct fluorescence detection of glutathione S-transferase (GST), a metabolic enzyme involved with crucial biological processes, in biological samples. After extracting and enriching the GST target from an aqueous-aqueous single-drop interface, the extraction process was conducted rapidly in 6 s in the SDMR system. The GST was first extracted from the sample solution via the GST-Aptamer on the polydopamine-coated vesicle/Fe3O4 nanospheres (Fe3O4@PDA@GST-Aptamer). Then, as the pH changed from weakly acidic to weakly alkaline in the SDMR system, the GST and GST-Aptamer were released from Fe3O4@PDA@GST-Aptamer nanospheres and captured by polydiacetylene vesicles via the capture probe. These changes altered the effective conjugation length and angle of the vesicle trunk, generating a highly enhanced fluorescence signal. This not only achieved the purpose of target enrichment but also reduced interferences posed by matrix effects. The approach can be used for the direct detection of GST in genuine urine and blood without any sample pretreatment. The linear range was 0.005 to 0.5 µg/mL, and the limit of detection was 0.834 ng/mL. The recoveries of GST in genuine blood samples ranged from 90.8 to 108.0% and in urine from 91.6 to 102.8%. The method has the capability of handling complex samples directly by enabling microextraction in an aqueous-aqueous single-drop system.

Three-Dimensional Printed Microdevice to Enhance Headspace Microextraction for Enrichment of Histamine in Milk.

In this work, a three-dimensional (3D) printed microdevice was designed to fix a drop of extractant that was applied to the enrichment of the most toxic biogenic amine, histamine, by headspace single-drop microextraction (HS-SDME). Concomitantly, based on the hybridization chain reaction of the histamine aptamer isothermal nucleic acid amplification strategy, a new fluorescence sensing method was developed to realize the highly sensitive detection of histamine. This is the first application of a 3D-printed microdevice to realize the HS-SDME process, which, among other advantages, effectively solves the problem of unstable and variable drop volumes that can plague traditional SDME and ensures the accuracy and repeatability of the extraction process. The calibration linear range of this SDME-fluorescence method was from 10 pM to 5 µM (R2 > 0.98), and the limit of detection was as low as 3 pM. In addition, the method was successfully demonstrated to determine histamine spiked in milk, with recoveries of between 93% and 104%, and relative standard deviations of less than 5%. The method established in this study has important practical significance for food safety monitoring and human health and provides new ideas and solutions for the design and application of biosensors.

Ultrahigh-Performance Supercritical Fluid Chromatography and Detection of Multiple Biogenic Amines in Gentamicin Sulfate: Method Development Using Computer-Assisted Modeling.

In order to solve the problem of difficult separation of various biogenic amines (BAs), which have similar structures or very different polarities, in gentamicin, by conventional liquid chromatography, a new ultrahigh-performance supercritical fluid chromatography (UHPSFC) method was developed. In this method, 10 BAs were derivatized precolumn using dansyl chloride and separated using a UHPSFC system. By computational simulation, complete separation of 10 BAs was successfully achieved. Detection was performed using a photodiode array (PDA) and single-quadrupole mass spectrometry (MS) together with electrospray ionization (ESI). A wide linear range (10-2500 ng/mL) was achieved, with the limits of detection (LODs) between 1.2 and 10.0 ng/mL and the limits of quantification (LOQs) between 5.0 and 25.0 ng/mL. Apart from high sensitivity, this UHPSFC-PDA/ESI-MS detection method also displayed high accuracy, the matrix effect was reduced by an appreciable extent, and the recovery rates of the 10 BAs were between 84.1 and 117.1%. For comparison, high-performance liquid chromatography-tandem mass spectrometry (MS/MS) was also used for the detection of underivatized BAs in gentamicin, showing good linearity and high sensitivity (LODs from 0.05 to 1.00 ng/mL and LOQs from 1.00 to 12.50 ng/mL) for all BAs except for spermine and spermidine. Although single-quadrupole MS is inferior to MS/MS in terms of sensitivity, the UHPSFC method could detect more BAs. It also achieved the quantification limits required for impurity determination, demonstrating a potential strategy to offer a map overview of possible BA presence in fermentation antibiotics.

Logarithmic Data Processing Can Be Used Justifiably in the Plotting of a Calibration Curve.

The article is a response to a recent opinion piece that log concentration values should not be applied in analytical chemistry. An essential aim in the development of analytical chemistry methods is to obtain more sensitive and accurate detection values. For the application of chemical analysis methods, the obtained experiment data need to fit with the mathematical functions in the first place. As influenced by different detection principles and analytical methods, data can be displayed in a coordinate system with two linear axes for linear function fitting, or the data can first be taken through a logarithmic transformation and then for function fitting. Using raw data or data after logarithmic transformation primarily depends on analytical principles, without special rules of data formats. For example, ultraviolet-visible spectrophotometric data are more suitable for direct linear fitting. However, enzyme-catalyzed reaction or electrochemical data in logarithmic form are more appropriate for function fitting. This transformation of data form will not affect the soundness of fit statistics; rather, it simplifies the complexity of function analysis and calculation, which are the essence of analytical chemistry. In this brief article, we provide justification and legitimacy of the application of logarithmic processing in various fields of quantitative analytical chemistry.

Solvent-loaded metal-organic framework of type MIL-101(Cr)-NH2 for the dispersive solid-phase extraction and UHPLC-MS/MS analysis of herbicides from paddy field waters.

A novel solvent-loaded dispersive solid-phase extraction (SL-DSPE) method integrated with liquid-phase microextraction (LPME) has been developed by the direct loading of solvent into the pores of a metal-organic framework (MOF), MIL-101(Cr)-NH2. Despite numerous advantages of MOFs, they are usually highly hydrophobic which limits their dispersibility and therefore effective contact with the analytes in aqueous samples. To overcome this and promote its interactions with polar compounds, MIL-101(Cr) was functionalized with -NH2 and loaded with a comparatively polar organic solvent, dichloromethane. The purpose of dichloromethane was to condition the MIL-101(Cr)-NH2, promote LPME of the analytes and facilitate the re-collection of the materials after the extraction. Five chlorophenoxy acid herbicides, including 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, 4-chlorophenoxyacetic acid, 2-(2,4-dichlorophenoxy)propionic acid, and 2-(2,4,5-trichlorophenoxy)propionic acid, were studied and determined by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). MIL-101(Cr)-NH2 was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and surface area measurement. Several extraction parameters were optimized, and under the most favorable conditions, the SL-DSPE-UHPLC-MS/MS method achieved enrichment factors between 25 and 66. Low limits of detection (2.66-19.7 ng·L-1) and wide dynamic working ranges with good linearity (r2 ≥ 0.991) were attained for all analytes. The method was repeatable, with intra- and inter-day relative standard deviations (RSDs) below 4.5 and 7.6%, respectively, for three replicate determinations. The application of SL-DSPE-UHPLC-MS/MS to paddy field waters gave satisfactory relative recoveries ranging between 80.2 and 108%, with RSDs better 8.4%. Several of the CPAs were detected in these samples. Graphical abstract Schematic of the solvent-loaded dispersive solid-phase extraction procedure. By directly loading dichloromethane into the pores of MIL-101(Cr)-NH2, this method improves the extraction capability of the sorbent through the combination of solvent- and sorbent-based microextraction.

Fully Automated Water Sampling-Surfactant-Enhanced Membrane Bag Liquid-Phase Microextraction-Ultrahigh Performance Liquid Chromatography-Mass Spectrometry.

A fully automated integrated analytical platform that included continuous water sampling, sample preparation (extraction), and analysis for the determination of nine glucocorticoids was developed. A peristaltic pump was employed to deliver the water sample automatically. The subsequent sample preparation and analytical processes were also fully automated with the use of a commercial autosampler unit coupled to an ultrahigh performance liquid chromatography-tandem mass spectrometric system. The sample preparation step involved membrane bag liquid-phase microextraction in which a synergistic mixture of n-octanol enhanced with surfactant sodium dodecyl sulfate (SDS) (0.10% in n-octanol) was applied as the extractant phase. Addition of SDS helped to improve the extraction, increasing enrichment factors (EFs) by severalfold compared with the use of n-octanol only as extractant solvent. Various parameters to improve extraction efficiency were evaluated. They included percentage of surfactant used, sample pH, agitation rate, extraction duration, salting out effect, extraction temperature, and flow rate for sample introduction. Under the most favorable conditions, enrichment factors of between 32 and 189 were attained with relative standard deviations of <8%. The limits of detection for the glucocorticoids were between 0.03 and 0.17 ng/mL, whereas the limits of quantitation were between 0.09 and 0.52 ng/mL, indicating the good sensitivity of the method. The method was successfully applied to determine glucocorticoids in industrial canal water. This work also provided some insights on the potential of on-site sampling and real-time monitoring of contaminants in environmental waters.

Highly Sensitive Detection of Multiple MicroRNAs by High-Performance Liquid Chromatography Coupled with Long and Short Probe-Based Recycling Amplification.

This report demonstrated the utility of high-performance liquid chromatography (HPLC)-fluorescence detection for selective separation and sensitive quantification of multiple microRNAs (miRNAs). A duplex specific nuclease (DSN)-assisted target recycling amplification strategy was developed to enhance the signals of miRNAs, which alleviates the low sensitivity of conventional HPLC to nucleic acids. To separate the signals of different miRNAs, DNA probes with different lengths and base sequences were immobilized on magnetic beads. The application of an effective magnetic separation minimized the background signal and extended the dynamic range. This assay achieved a limit of detection of 0.39 fM for miRNA-122, 0.30 fM for miRNA-155, and 0.26 fM for miRNA-21, respectively. The proposed assay was successfully applied to detect simultaneously miRNA-122, miRNA-155, and miRNA-21 in serum samples from healthy persons and cervical cancer patients, and the results were then compared with those of quantitative real-time-polymerase chain reaction amplification.

Magnetic Three-Phase Single-Drop Microextraction for Rapid Amplification of the Signals of DNA and MicroRNA Analysis.

The detection of nucleic acids usually suffers from a lengthy amplification process. To obtain an enhanced signal within several seconds, a magnetic three-phase single-drop microextraction (MTP-SDME) approach was developed for the quantification of nucleic acids. First, a target-triggered recycling amplification strategy was used to constitute magnetic branched DNA/Fe3O4 networks, which displayed peroxidase-like catalytic activity toward the 3,3',5,5'-tetramethylbenzidine colorimetric reaction. The networks were separated and enriched by rapid (6 s) MTP-SDME (with only 6 µL of solvent required), thereby producing highly sensitive signals for the quantification of nucleic acids. The signals were significantly amplified by the triple strategy (network formation, MTP-SDME, and catalytic reaction). The application of magnetic extraction minimized the background signal, avoided sample matrix effects, and enhanced the analyte signals. This assay achieved linear calibration curves of between 0.5 aM and 1 pM for microRNA-122 (miRNA-122) and between 1 aM and 1 pM for HBV-T (a DNA fragment from hepatitis B virus). Limits of detection of 0.15 aM for miRNA-122 and 0.34 aM for HBV-T were attained, with relative standard deviations of <5.0% (n = 3). Furthermore, the procedure was applied to determine miRNA-122 and HBV-T in genuine serum samples from hepatocellular carcinoma patients.

Graphitic carbon nitride as sorbent for the emulsification-enhanced disposable pipette extraction of eight organochlorine pesticides prior to GC-MS analysis.

Graphitic carbon nitride (g-C3N4) was explored as a sorbent for the emulsification-enhanced (EE) disposable pipette extraction (DPX) of eight organochlorine pesticides (OCPs) from environmental waters. The OCPs, including α-hexachlorocyclohexane, Aldrin, α-Chlordane, Dieldrin, 4,4'-dichlorodiphenyldichloroethylene, 4,4'-dichlorodiphenyldichloroethane, Heptachlor and Heptachlor epoxide (Isomer A), were analyzed by gas chromatography-mass spectrometry. The sorbent g-C3N4 was characterized by elemental analysis, X-ray diffraction, scanning electron microscopy, Fourier-transform infrared and Raman spectroscopy. As a C-N analogue of graphite, g-C3N4 exhibits good water dispersibility and allows easy analyte recovery - a characteristic not commonly observed in carbon-based materials. When applied to DPX, g-C3N4 rapidly establishes strong interactions with the OCPs. Consequently, g-C3N4 displays superior extraction capability in comparison to six other commercial sorbents. An emulsification step prior to DPX was found to enhance the overall extraction efficiency by pre-concentrating the OCPs into the microdroplets of an organic solvent. The microdroplets were then adsorbed onto g-C3N4. Under the most favorable conditions, wide linear responses spanning over two to four orders of magnitudes are established. The limits of detection range between 2.4 ng·L-1 and 46.2 ng·L-1. The method is reproducible (relative standard deviations ≤ 7.4%) and enrichment factors are between 42 and 57. When applied to the analysis of lake and river water samples, EE-DPX-gas chromatography-mass spectrometry exhibits good resilience against matrix interferences. The relative recoveries range between 77.7% and 106.3%. In comparison to other sorbent-based extraction techniques reported for the analysis of OCPs in aqueous samples, EE-DPX utilizes the minimal amount of sample and solvent, and requires the shortest sample preparation time. Graphical abstractSchematic representation of the emulsification-enhanced disposable pipette extraction (DPX) of organochlorine pesticides (OCPs) using graphitic carbon nitride (g-C3N4) as sorbent. Emulsification and DPX work synergistically, thus allowing rapid dissolution of analytes into microdroplets of organic solvent, before being extracted by g-C3N4.

Smartphone Nanocolorimetric Determination of Hydrogen Sulfide in Biosamples after Silver-Gold Core-Shell Nanoprism-Based Headspace Single-Drop Microextraction.

In this work, the sensitive detection of hydrogen sulfide (H2S) was realized at low cost and high efficiency through the application of silver-gold core-shell nanoprism (Ag@Au-np) combined with headspace single-drop microextraction (HS-SDME). After SDME, smartphone nanocolorimetry (SNC), with the aid of a smartphone camera and color picker software, was used to detect and quantify the H2S. The method took advantage of the inhibition of the ultraviolet-visible (UV-vis) signal caused by H2S etching of the Ag@Au-np preadded to the SDME solvent to measure the H2S concentration. The coating of the gold layer not only ensured the high stability of the nanomaterial but also enhanced the selectivity toward H2S. The HS-SDME method was simple to process and required only a droplet of solvent for analysis to be realized. This HS-SDME-SCN approach exhibited a calibration graph linearity of between 0.1 and 100 µM and a limit of detection of 65 nM (relative standard deviations of N% ( n = 3) < 4.80). A comparison with UV-vis spectrophotometry was conducted. The practical applicability of HS-SDME-SNC was successfully demonstrated by determining H2S in genuine biosamples (egg and milk).

A metal-organic framework of type MIL-101(Cr) for emulsification-assisted micro-solid-phase extraction prior to UHPLC-MS/MS analysis of polar estrogens.

A seamless two-step extraction procedure integrating ultrasound-assisted emulsification microextraction (USAEME) and vortex-assisted micro-solid-phase extraction (µ-SPE) was developed. A highly porous metal-organic framework of type MIL-101(Cr) is used as the sorbent, and ultra-high-performance liquid chromatography in combination with tandem mass spectrometry is used for detection. The steroid hormones estrone 17ß-estradiol, estriol, and 17α-ethynylestradiol were extracted from water samples by using this method. These steroids are polar and do not pass through the polypropylene membrane that is conventionally used in µ-SPE. In the method presented here, 1-octanol is used in USAEME to extract and pre-concentrate the steroids. This facilitates the transfer to the MIL-101(Cr) phase retained by the membrane in the subsequent µ-SPE step. MIL-101(Cr) was characterized by various methods, and the parameters affecting the overall extraction efficiency were optimized. Under the most favorable conditions, the limits of detection are between 0.95 and 23 ng L-1. Good intra-day and inter-day precisions were obtained, with relative standard deviations of ≤ 9.9%. Enrichment factors are between 34 and 52. The method was applied to genuine environmental water samples in which estrone was detected. Relative recoveries ranged between 85.4% and 120.8%. Graphical abstract Schematic of the emulsification-assisted micro-solid-phase extraction (µ-SPE). By emulsifying 1-octanol in the water sample, polar estrogens dissolved in the solvent can easily pass the hydrophobic polypropylene membrane and then are adsorbed onto the unmodified MIL-101(Cr) held within the µ-SPE device.

A hydrogel composite prepared from alginate, an amino-functionalized metal-organic framework of type MIL-101(Cr), and magnetite nanoparticles for magnetic solid-phase extraction and UHPLC-MS/MS analysis of polar chlorophenoxy acid herbicides.

A regenerable hydrogel composite is described that is comprised of alginate, amino-functionalized metal-organic framework (MIL-101(Cr)-NH2) and magnetite nanoparticles. The composite was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, vibrating-sample magnetometry and Brunauer-Emmett-Teller measurement. The material was applied to the magnetic solid-phase extraction of six polar chlorophenoxy acid (CPA) herbicides. Specifically, the herbicides clofibric acid, 4-chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, 2-(2,4-dichlorophenoxy)propionic acid, 2,4,5-trichlorophenoxyacetic acid and 2-(2,4,5-trichlorophenoxy)propionic acid were extracted from environmental aqueous samples and analyzed by ultra-HPLC-tandem mass spectrometry. The abundance of hydroxyl and carboxyl groups on the natural polymer renders alginate a superior hydrophilic coating. It brings the polar acidic herbicides into closer proximity to the porous metal-organic framework. When integrated with MIL-101(Cr)-NH2, the composite material combines the favorable attributes of high hydrophilicity and large adsorption capacity. An orthogonal array design matrix was employed for the optimization of the extraction parameters. Under the most favorable conditions, the method displays a wide linear response and low limits of detection (0.43-16 ng⋅L-1). Precision and reproducibility (with relative standard deviations of ≤13%) are satisfactory. Enrichment factors range between 27 and 107. The composite was applied to the extraction of CPA herbicides from lake and pond water samples. A markedly improved sorbent-based extraction procedure and performance (compared to previous methods) is found. Graphical abstract Schematic of the magnetic solid-phase extraction of polar herbicides using a hydrogel composite as sorbent. The amino-functionalized MIL-101(Cr) and hydrophilic alginate work in synergy resulting in a material which possess favorable attributes of both components that are beneficial for extraction.