Graphene for Cleanup in Trace Analysis of Pyrethroid Insecticides in Cucumber and Spinach

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.

Dissipation and safety evaluation of afidopyropen and its metabolite residues in supervised cotton field

The novel insecticidal mechanism of afidopyropen can be substituted for traditional pesticides to control sap-sucking pests in cotton field. The data of residue amounts of afidopyropen and its metabolite M440I007 in cotton matrix and the environment soil are important to evaluate the safe use of the target compound and establish maximum residue limit (MRL). In this work, the dissipation and residue of afidopyropen and its metabolite M440I007 in cotton and field soils were investigated. The analytical methods of the target compound in cotton plants, cottonseed, crude cottonseed oil, cottonseed oil and soil were developed and quantified by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), which satisfied the rules of pesticide residue determination. The dissipation half-lives of afidopyropen in cotton plants and soil ranged from 1 to 3 days and 4-13 days, respectively. After 14 days from the last application, the residues of afidopyropen were below 0.01 mg/kg in cottonseed and were <0.005-0.0099 mg/kg in soil, and the residues of M440I007 were below 0.02 mg/kg in cottonseed and below 0.01 mg/kg in soil. The total national estimated daily intake (NEDI) of afidopyropen was 1.41 mg and the risk quotient (RQ) was 28.0%. The results showed that the risk of application of afidopyropen with the recommended dosage was acceptable.

The Potential of Graphene as an Adsorbent for Five Pesticides from Different Classes in Rape Oil Samples Using Dispersive Solid-Phase Extraction

Isolation conditions for five pesticides (metazachlor, tebuconazole, λ-cyhalothrin, chlorpyrifos, and deltamethrin) from rape oil samples were examined using the dispersive solid-phase graphene extraction technique. To determine the optimal extraction conditions, a number of experimental factors (amount of graphene, amount of salt, type and volume of the desorbing solvent, desorption time with and without sonication energy, and temperature during desorption) were studied. The compounds of interest were separated and detected by an HPLC-UV employing a Kinetex XB-C18 column and a mobile phase consisting of acetonitrile and water flowing in a gradient mode. The optimized extraction conditions were: the amount of graphene 15 mg, desorbing solvent (acetonitrile) 5 mL, time desorption 10 min at 40°C, and amount of NaCl 1 g. The detection limit for metazachlor, tebuconazole, λ-cyhalothrin, and chlorpyrifos was 62.5 ng·g^-1, and for deltamethrin, it was 500 ng·g^-1. The obtained results lead to the conclusion that graphene may be successfully used for the isolation of the five pesticides from rape oil. However, their determination at low concentration levels, as they occur in real oil samples, requires the employment of appropriately highly sensitive analytical methods, as well as a more suitable graphene form (e.g., magnetically modified graphene).

Amine modified graphene as reversed-dispersive solid phase extraction materials combined with liquid chromatography-tandem mass spectrometry for pesticide multi-residue analysis in oil crops

Amine modified graphene is successfully synthesized via a one-pot solvothermal reaction between graphene oxide and ammonia water, methylamine or n-butyl amine. The presence of amine groups in graphene is identified by Fourier-transform infrared spectrometry, X-ray photoelectron spectroscopy and an X-ray diffractometer. The ability of amine modified graphene to cleanup fatty acids and other interfering substances from acetonitrile extracts of oil crops has been evaluated. It is found that the resulting CH3NH-G exhibits the best performance in interfering substances removal. Meanwhile, a multi-residue method is validated on 28 representative pesticide residues in four oil crops (rapeseed, peanut, sesame seeds and soybean). This method is based on modified QuEChERS sample preparation with CH3NH-G as reversed-dispersive solid phase extraction material and liquid chromatography-tandem mass spectrometry. Use of matrix-matched standards provides acceptable results for most pesticides with overall average recoveries between 70.5 and 100% and consistent RSDs<13%, except for pymetrozine, thidiazuron and diuron. In any case, this method still meets the 0.1-8.3 μg/kg detection limit needs for most pesticides and may be used for qualitative screening applications, in which any identified pesticides can be quantified and confirmed by a more intensive method that achieves >70% recovery.