Preparation of Graphene Sheets with Covalently Bonded Fe3O4 for Magnetic Solid-Phase Extraction Applied to Organochlorine Pesticides in Orange Juice

Graphene-based nanomaterials as potential candidates for environmental mitigation of pesticides

Over the years, bioaccumulation of hazardous chemicals in the food chain has become a critical issue, resulting in numerous health risks. Environmental mitigation aims to clean up contaminated sites and eliminate hazardous materials from the air, water, or soil to restore the site to its original and safe condition. Pesticides constitute one of the most dangerous environmental pollutants which are generally used to increase crop production. Addressing the removal or treatment of pesticides has become pivotal in mitigating environmental threats. Diverse remediation methods are employed to protect the environment and public health. Graphene-based materials have emerged as promising candidates with exceptional properties, including excellent adsorption capacity due to their high surface area, strong hydrophilicity, and tunable properties. Owing to these properties, they have been attracting major research attention in the field of design and fabrication of materials for the mitigation of pesticides from the environment such as from contaminated food, water and other samples. Various physical, chemical and biological extraction techniques are adopted to remove pesticides. This review article provides an insight into the potential role of graphene-based materials in the environmental remediation of pesticides. We have focused on the removal of Organophosphates, Organochlorines, Carbamates and Pyrethroids present in water, fruit, vegetable and other samples, highlighting the urgent need for environmental remediation. While graphene-based materials hold potential for pesticide remediation, addressing challenges in scalable production, assessing long-term sustainability, and mitigating potential environmental impacts are critical steps for successful large-scale applications.

A ternary deep eutectic solvent-modified magnetic mixed iron hydroxide@MIL-101(Cr)-NH2 composite as a sorbent in magnetic solid phase extraction of organochlorine pesticides prior to GC-MS

A green solvent of ternary deep eutectic solvent (menthol-thymol-dodecanoic acid) was prepared and used as a functional reagent to modify a magnetic mixed iron hydroxide@MIL-101(Cr)-NH₂ composite. The proposed sorbent (MIH@MIL-101(Cr)-NH₂-TDES) was applied in magnetic solid phase extraction (MSPE) for the enrichment of organochlorine pesticides. The analytes were quantitively analyzed by GC-MS. The relationships of experimental parameters for preparing the proposed sorbent and the MSPE method were studied through a Box-Behnken design and a central composite design, respectively. Their optimized conditions were investigated using response surface methodology. Application of the MIH@MIL-101(Cr)-NH₂-TDES sorbent in MSPE successfully enhanced the sensitivity of GC-MS analysis, giving enrichment factors in the range of 56-168. The MSPE/GC-MS method was developed using MIH@MIL-101(Cr)-NH₂-TDES as a sorbent and was successfully employed for the preconcentration/determination of organochlorine residues in honey and tea samples. The satisfactory detection limits were in the ranges of 0.07-0.80 ng g^-1 and 0.7-8.5 ng g^-1 for honey and tea samples, respectively. Acceptable recoveries were obtained in the ranges of 81.7-107.3% and 85.4-109.3% for the spiked honey and tea samples, respectively, with RSDs lower than 10.0%.

Magnetic polyamidoamine dendrimers for magnetic separation and sensitive determination of organochlorine pesticides from water samples by high-performance liquid chromatography

Organochlorine pesticides (OCPs) have received much attention due to their toxicity. Reliable methods to monitor their residues in the environment are needed. Here, magnetic polyamidoamine dendrimers were prepared by co-precipitation, Michael addition, and amidation. The magnetic polyamidoamine dendrimers demonstrated good adsorption ability for OCPs-this feature was utilized to construct a sensitive tool for monitoring OCPs in water samples. The proposed method provided remarkable linearity from 0.1 to 500 μg/L and satisfactory limits of detection from 0.012 to 0.029 μg/L. The spiked recoveries of the four target analytes were 91.8%-103.5% with relative standard deviations less than 4.5%. The magnetic materials had good reusability. The results indicated that the resulting method was an efficient, easy, rapid, economical, and eco-friendly tool for monitoring OCPs in aqueous samples.

Fe3O4 nanoparticles as matrix solid-phase dispersion extraction adsorbents for the analysis of thirty pesticides in vegetables by ultrahigh-performance liquid chromatography-tandem mass spectrometry

Herein we report the first example of Fe₃O₄ nanoparticles (FNPs) being used as single-matrix solid-phase dispersion (MSPD) adsorbents for the extraction of 30 representative pesticides from vegetables. This study was aimed at analyzing the extracted samples using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Various condition parameters, such as the eluent, volume of the eluent, and amount of FNPs were optimized to achieve good sensitivity and precision for the elution and extraction of the analytes. The developed method was validated using matrices consisting of eight vegetables (lettuce, cucumber, carrot, tomato, pepper, shallot, Chinese flowering cabbage, and cabbage) spiked with 30 pesticides at concentrations of 0.01, 0.1, and 1.0 mg/kg. The recoveries of the 30 pesticides (organophosphorus, triazole, carbamate, nicotine, amide, and other different structures of pesticides) were in the range 71.0-110.8% (n = 5) (except those of prothioconazole and dinotefuran), with relative standard deviations lower than 13.5% in all the matrices under optimal conditions. The matrix effects were observed by comparing the slope of the matrix-matched standard calibration curve with that of the solvent. However, the matrix effects of the eight vegetables did not show evident regularities. For pepper, tomato, and shallot, a sizable number of pesticides (24, 21, and 21, respectively) showed suppressive matrix effects. On the other hand, for cucumber, Chinese flowering cabbage, and cabbage, a good number of pesticides (19, 18, and 15, respectively) showed negligible matrix effects. Furthermore, for carrot matrices, 21 pesticides showed a matrix enhancement effect. Excellent linearity was achieved at pesticide concentrations of 0.01-1.0 mg/L, and the limits of quantification (LOQ) for the developed method reached 0.01 mg/kg (except that for dinotefuran, which was 0.1 mg/kg), based on the spiked test. The developed method was successfully employed in the analysis of real samples in Nanning, China, and three pesticide residues (halosulfuron methyl, tebuconazole, and azoxystrobin) were commonly detected in vegetable samples. In the present study, a reliable method-validation performance and excellent cleanup effects were observed by using the modified MSPD method consisting of the FNPs in the cleanup step.