Solid-phase Extraction Of Organophosphorus Pesticides Research Articles

Metal-organic frameworks modified melamine foam in pipette-tip for rapid solid-phase extraction of organophosphorus pesticides in fruits and vegetables.

In this work, metal-organic frameworks (MOFs) including Fe-MIL-101 and Ti-MIL-125 were prepared and fixed on the melamine foam (MF) by polyvinylidene fluoride (PVDF) to prepare MF/PVDF/MOFs, which was used as adsorbents in pipette-tip solid-phase extraction (PT-SPE) for rapid extraction of organophosphorus pesticides (OPPs). Then, a gas chromatograph-flame thermionic detector (GC-FTD) was used for simultaneous analysis of Dimethoate (DMT), Iprobenfos (IBF), Parathion-methyl (PAM), and Chlorpyrifos (CPF). The morphology, crystal structure, and functional groups of MF/PVDF/MOFs were characterized, indicating that Ti-MIL-125 and Fe-MIL-101 were successfully synthesized and distributed on MF. The Fe-MIL-101 and Ti-MIL-125 showed good extraction ability for OPPs, which was mainly due to the π-π interaction and the multiple porous structures. Under the optimal conditions, the limit of detection (LODs) of four OPPs was 0.03-0.14μg L-1 and the RSDs were less than 9.9%. The developed PT-SPE method showed a short extraction time (<3min). The recoveries in fruits and vegetables (Celery, cabbages, and oranges) ranged from 75.3%-118.8% (RSDs<9.6%). The prepared MF/PVDF/MOFs demonstrated the efficient extraction performance of OPPs, contributing to the rapid pretreatment of OPPs from food and the environment.

Synthesis of oil palm empty fruit bunch-based magnetic-carboxymethyl cellulose nanofiber composite for magnetic solid-phase extraction of organophosphorus pesticides in environmental water samples

This study investigated the development of a magnetic-carboxymethyl cellulose nanofiber (Fe3O4-cmCNF) composite from oil palm empty fruit bunch (OPEFB) as a promising adsorbent for the determination of organophosphorus pesticides (OPPs) in water samples via the magnetic solid-phase extraction (MSPE). The Fe3O4-cmCNF was prepared via the alkaline method and surface-modified using the carboxymethylation and sol–gel technique. The physicochemical characteristics of the Fe3O4-cmCNF were evaluated via FT-IR, VSM, SEM, TEM, XRD, TGA, and BET analysis. Diazinon, fenitrothion, and malathion were selected as the model analytes to examine the feasibility and performance of the Fe3O4-cmCNF-based MSPE to detect OPPs in real environmental water samples using gas chromatography-micro-electron capture detector (GC-µECD). Experimental parameters that affected the extraction efficiency were optimized, including the type and amount of adsorbent, extraction time, pH, type of elution solvent, and ionic strength. Based on the results, the prepared adsorbent showed a high affinity towards OPPs through hydrogen bonding as well as hydrophobic and electrostatic interaction. Under optimum conditions, the linear calibration curves were achieved for diazinon, fenitrothion, and malathion with a concentration range of 0.1–200 ng mL−1 and a suitable determination coefficient (r2) between 0.9962 and 0.9995. Furthermore, acceptable intra- and inter-day precisions were obtained between the range 1.7–4.9 % and 2.0–14.0 %, respectively. The LOD for diazinon, fenitrothion, and malathion was determined at 0.03 ng mL−1, with a satisfactory relative recovery range of 81.8–119.6 %. OPPs residues were detected in river water (0.27–0.39 ng mL−1) and wastewater (0.41–1.31 ng mL−1), indicating that the Fe3O4-cmCNF is a suitable composite for the determination of OPPs in real samples.

Magnetic solid-phase extraction of organophosphorus pesticides from apple juice and environmental water samples using magnetic graphene oxide coated with poly(2-aminoterephthalic acid-co-aniline) nanocomposite as a sorbent.

An effective magnetic solid-phase extraction method was proposed using magnetic graphene oxide coated with poly(2-aminoterephthalic acid-co-aniline) as a sorbent for preconcentration and extraction of organophosphorus pesticides from environmental water and apple juice samples, and determined using the gas chromatography-mass spectrometry analysis. To approve the successful synthesis of the magnetic nanocomposite, the prepared sorbent was characterized by field emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometer, and Fourier transforms infrared techniques. The main parameters affecting the extraction efficiency were considered and studied to afford an optimized procedure. Systematic method validation verified its suitable recoveries (89.4-107.3%), and precision (relative standard deviations<6.8%). The method showed a wide linear dynamic range (0.04-700ng/mL) with low limits of detection (0.01-0.06ng/mL) and quantification (0.04-0.21ng/mL). This method presented good potential and great sensitivity for the pesticides determination.

Synthesis of Oil Palm Empty Fruit Bunch-Based Magnetic-Carboxymethyl Cellulose Nanofiber Composite for Magnetic Solid-Phase Extraction of Organophosphorus Pesticides in Environmental Water Samples

Synthesis of Oil Palm Empty Fruit Bunch-Based Magnetic-Carboxymethyl Cellulose Nanofiber Composite for Magnetic Solid-Phase Extraction of Organophosphorus Pesticides in Environmental Water Samples

Synthesis of metal-organic framework @molecularly imprinted polymer adsorbents for solid phase extraction of organophosphorus pesticides from agricultural products

The novel core-shell structural zeolitic imidazolate framework-8 @molecularly imprinted polymers were successfully synthesized by surface imprinting technique and used as adsorbents for solid-phase extraction of organophosphorus pesticides. The obtained hybrid composites were characterized by scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared, and their adsorbing and recognition performance were evaluated by binding experiments. The results showed that zeolitic imidazolate framework-8 @molecularly imprinted polymers presented a typically core-shell structure with molecularly imprinted shell (about 50 nm) homogeneously polymerized on the surface of zeolitic imidazolate framework-8 core, and exhibited specific recognition towards organophosphorus pesticides with fast adsorption capacity. The adsorption and desorption conditions including sample loading solvent, sample pH, washing and elution solvent were optimized. Under optimum conditions, the solid-phase extraction based on zeolitic imidazolate framework-8 @molecularly imprinted polymers combined with high liquid chromatography-tandem mass spectrometry method for determining organophosphorus pesticides was established and exhibited good linearity (R2 ≥ 0.9927) in the range of 1–200 µg/L. With spiked at three different concentration levels in agricultural products (cauliflower, radish, pear, muskmelon), the recoveries ranged from 82.5% to 123.0% with relative standard deviations lower than 8.24%. The developed method was sensitive, convenient and efficient. More importantly, this study could provide a promising strategy for designing new adsorbents with extremely fast mass transfer rate for other potential trace contaminants.

Preparation of magnetic flower-like molybdenum disulfide hybrid materials for the extraction of organophosphorus pesticides from environmental water samples

In this study, the magnetic flower-like molybdenum disulfide hybrid materials (Fe3O4/MoS2) were successfully synthesized by in-situ fabrication method and utilized in the magnetic solid-phase extraction of organophosphorus pesticides. Fe3O4 nanoparticles with different loading amounts of MoS2 were evaluated and detail characterized. The results showed that MoS2 played a key role with rapid and high adsorption capacity towards organophosphorus pesticides. The higher extraction efficiency and good magnetic performance were obtained with loading amount of 200 mg MoS2. Fe3O4 was attached on the surface of MoS2 with flower-like shape (500 nm in diameter). The parameters (amounts of adsorbents, adsorption time, solution pH, elution solvents and sample volumes) affecting magnetic solid-phase extraction efficiency were optimized. Under the optimum conditions, magnetic solid-phase extraction coupled with high liquid chromatography-tandem mass spectrometry for analyzing organophosphorus pesticides in environmental water samples was established. All the analytes exhibited good recoveries spiked at three different concentration levels (10, 20, 50 ng/mL) in water samples. The relative standard deviations were between 1.4% and 6.8%. The developed method showed high sensitivity and good potential use of this convenient and high efficient method for determining organophosphorus pesticides. More importantly, this study can provide a new magnetic adsorbent with extremely fast mass transfer rate for other potential trace contaminants.

Selective solid-phase extraction of organophosphorus pesticides and their oxon-derivatives from water samples using molecularly imprinted polymer followed by high-performance liquid chromatography with UV detection.

A molecularly imprinted polymer was synthesized and characterized to be used as solid-phase extraction sorbent for simultaneous chlorpyrifos and diazinon and their oxon derivatives. Several imprinted polymers were prepared and evaluated in a retention study of these analytes compared with a non-printed polymer. Several parameters affecting the extraction of imprinted polymer such as washing solvent, composition and volume of the eluting solvent and sample volume, were also investigated. Under the optimum conditions, the developed method provided satisfactory limits of detection ranging between 0.07 µg L-1 to 0.12 µg L-1 and the material showed an excellent reusability (> 50 reuses). The method was applied to the extraction and preconcentration of these analytes in water samples. The average recoveries ranged from 79 ± 6 to 104 ± 3 %.

Facile magnetization of metal–organic framework TMU-6 for magnetic solid-phase extraction of organophosphorus pesticides in water and rice samples

In the present work, a magnetic metal-organic framework composite (Fe3O4@TGA@TMU-6) was synthesized and used as an adsorbent for magnetic solid-phase extraction (MSPE) of some organophosphorus pesticides (phosalone, chlorpyrifos and, profenofos) in rice and environmental water samples. Extraction, separation and determination of the analytes were performed by MSPE-HPLC-UV. Due to the large surface area and unique porous structure of the metal-organic frameworks (MOFs) as well as π-π and hydrophobic interactions between the analytes and the MOF ligands, the prepared sorbents showed a high affinity towards the target analytes. The affecting parameters on the extraction efficiency, including type and volume of eluent, pH, amount of MFC, extraction time, salt effect and desorption time were investigated and optimized. Under optimum conditions, calibration curves were found to be linear in the range of 7.5–75 μg L−1, 10–100 μg L−1, and 10–150 μg L−1 for phosalone, chlorpyrifos, and profenofos in water samples, respectively. The LODs (based on S/N = 3) were 0.5, 1 and 0.5 μg L−1 for phosalone, chlorpyrifos, and profenofos in water samples, respectively.

Fabrication of a novel azamacrocycle-based adsorbent for solid-phase extraction of organophosphorus pesticides in tea drinks

A novel azamacrocycle-based adsorbent for solid-phase extraction was synthesized by coupling a 26-membered aromatic-aliphatic-mixed azamacrocycle to 3-chloropropyltrimethoxylsilane-modified silica. The obtained material was characterized by elemental analysis and fourier transform-infrared spectroscopy. The adsorbent showed excellent performance for extracting organophosphorus pesticides (fenitrothion, parathion, fenthion and phoxim), which may be due to multiple interactions between the adsorbent and organophosphorus pesticides, including π–π, hydrophobic, dipole-dipole, charge-transfer, hydrogen-bonding and inclusion interactions. The main parameters that affected the extraction efficiency were investigated, including the amount of adsorbent, the volume and flow rate of the sample solution, the elution solvent and the ionic strength. This azamacrocycle-based extraction technique was further combined with high-performance liquid chromatography to measure trace organophosphorus pesticides in tea drinks. The method showed good linearity (5–500 ng/mL), low limit of detection (0.10 ng/mL), and high recoveries from spiked samples (90.4%–113.5%) were obtained with low relative standard deviation (0.6%–8.9%, n = 3). The azamacrocycle-based adsorbent showed good extraction performance and offered a promising application in the extraction of organophosphorus pesticides from complicated tea drinks.

Magnetic solid-phase extraction of organophosphorus pesticides from fruit juices using NiFe2O4@polydopamine@Mg/Al-layered double hydroxides nanocomposites as an adsorbent

Herein, we developed a novel three-layer nanocomposite for adsorption/extraction of organophosphorus pesticides in fruit juice samples. This magnetic nanocomposite was fabricated by coating polydopamine and Mg/Al layered double hydroxides onto NiFe2O4 nanoparticles, which overcomes the shortcomings of low surface area and easy agglomeration associated with conventional Fe-based crystal nanoparticles. Additionally, the higher dispersibility of polydopamine and larger specific surface area of Mg/Al layered double hydroxides are conducive to rapid dispersion and efficient adsorption of organophosphorus pesticides by the synthesized nanocomposites, thereby greatly improving the efficiency of magnetic solid-phase extraction. The extraction method based on as-synthesized nanocomposites provided average extraction recoveries of 84.9% for methamidophos, parathion and phoxim, an increase of ca. 30% and 19% over those of NiFe2O4 and NiFe2O4@polydopamine, respectively. The main operational parameters were firstly screened and then optimized using Plackett-Burman and central-composite design, respectively. Under optimized conditions, this proposed method yielded low detection limits (0.06–0.13 μg L−1) and high intra- and inter-day precisions (2.7–4.5%). Average extraction recoveries for organophosphorus pesticides were 81.8–94.4% in grape, apple, orange, peach and mango fruit juices. To sum up, it integrates highly efficient preconcentration/extraction/dispersion, as well as rapid separation/collection into one synchronous step, satisfies the technical requirement of modern analytical pretreatment and thus enriches the multi-functional application of Fe-based nanoparticles.

Synthesis of a zinc-based metal-organic framework with histamine as an organic linker for the dispersive solid-phase extraction of organophosphorus pesticides in water and fruit juice samples

As a highly efficient adsorbent, the zinc-based metal-organic framework has been successfully synthesized from zinc as the metal ion and histamine as an organic linker under solvothermal conditions. The structure of nanocomposite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) analysis. The synthesized sorbent was applied for dispersive solid-phase extraction (DSPE) of organophosphorus pesticides (OPPs) in fruit juice and water samples. The gas chromatography-flame ionization detector (GC-FID) was used as instrument detection. The main experimental factors affecting the extraction efficiency such as the desorption conditions, sorbent amount and extraction time were evaluated and optimized. Good linearity exhibited for all of the target analytes in the 0.1–100 ng mL−1 concentration range. The enrichment factors (EFs) ranged from 803 to 914. The limits of detection (LODs) for the established DSPE-GC-FID method were found to be 0.03–0.21 ng mL−1. The DSPE-GC-FID method can be used for the analysis of OPPs in water and fruit juice samples with recoveries of the analytes in the range of 91.9% to 99.5%.

Novel restricted access materials combined to molecularly imprinted polymers for selective solid-phase extraction of organophosphorus pesticides from honey

A novel restricted access materials (RAM) combined to molecularly imprinted polymers (MIPs), using malathion as template molecule and glycidilmethacrylate (GMA) as pro-hydrophilic co-monomer, were prepared for the first time. RAM-MIPs with hydrophilic external layer were characterized by scanning electron microscopy and recognition and selectivity properties were compared with the restricted access materials-non-molecularly imprinted polymers (RAM-NIPs) and unmodified MIPs. RAM-MIPs were used as the adsorbent enclosed in solid phase extraction column and several important extraction parameters were comprehensively optimized to evaluate the extraction performance. Under the optimum extraction conditions, RAM-MIPs exhibited comparable or even higher selectivity with greater extraction capacity toward six kinds of organophosphorus pesticides (including malathion, ethoprophos, phorate, terbufos, dimethoate, and fenamiphos) compared with the MIPs and commercial solid phase extraction columns. The RAM-MIPs solid phase extraction coupled with gas chromatography was successfully applied to simultaneously determine six kinds of organophosphorus pesticides from honey sample. The new established method showed good linearity in the range of 0.01–1.0μgmL−1, low limits of detection (0.0005–0.0019μgmL−1), acceptable reproducibility (RSD, 2.26–4.81%, n=6), and satisfactory relative recoveries (90.9–97.6%). It was demonstrated that RAM-MIPs solid phase extraction with excellent selectivity and restricted access function was a simple, rapid, selective, and effective sample pretreatment method.

Dispersive solid-phase extraction of organophosphorus pesticides from apple, cucumber and water samples using reduced graphene oxide coated with ZnO nanocomposites as a sorbent

RGO–ZnO nanocomposites were synthesized and used as DSPE adsorbent for enriching OPs in apple, cucumber and water samples.

Selective and Simultaneous Solid Phase Extraction of Polar and Non–Polar Organophosphorus Pesticides Using Sol–Gel Hybrid Silica–Based Sorbent

A new sol–gel hybrid silica–based sorbent, methyltrimethoxysilane–cyanopropyltriethoxysilane (MTMOS–CNPrTEOS) produced in our laboratory was used for highly selective and simultaneous solid phase extraction (SPE) of two polar organophosphorus pesticides (OPPs) and four non–polar OPPs from water samples. The two polar OPPs used as test analytes are dicrotophos and methamidophos while the four non–polar OPPs are diazinon, malathion, methidathion, and chlorpyrifos. Analysis of OPPs was performed using gas chromatography–mass spectrometry in scan mode. Extraction efficiency (based on peak area response) of the new sol–gel hybrid MTMOS–CNPrTEOS was superior to commercial C18 SPE sorbent. The new sorbent showed higher selectivity towards the polar dicrotophos and methamidophos and it was also able to simultaneously extract the four non–polar OPPs with higher extraction efficiency. The limit of detection at S/N=3 for the new sol–gel hybrid sorbent is 5–9× lower and similar accuracy for the six OPPs compared to commercial C18 SPE sorbent. The new sol–gel hybrid material showed high potential as an alternative sorbent material for solid phase extraction of OPPs of wide polarity. It was successfully applied to the selective and simultaneous extraction the six OPPs from tap water and lake water samples.