Carbonized polydopamine as coating for solid-phase microextraction of organochlorine pesticides

Recent Development of Versatile Polyphenol Platforms in Fertilizers and Pesticides

The utilization of agrochemicals has been of significant importance in both the cultivation and disease control of crops. The development of advanced agrochemicals that are both effective and eco-friendly has been made possible through the use of slow delivery platforms and surface modification technology. Inspired by the nature of mussel adhesion, polyphenolic platforms with versatile properties have been extensively employed in various applications, including agro-food, owing to their ability to flexibly modulate chemical and surface characteristics. This mini-review highlights the development of polyphenols, such as polydopamine and tannic acid, in the field of agrochemicals, particularly in the design and production of novel fertilizers and pesticides. The synthetic approach, active ingredient release performance, foliar adhesion, and design of polyphenolic-based agrochemicals in recent years have been discussed to explore their potential applications and limitations. We believe that utilizing versatile polyphenolic materials and their characteristics for agro-food applications can provide innovative ideas and suggestions for developing novel agrochemicals suitable for modern and sustainable horticulture and agriculture.

Cellulose Nanocrystals Induced Loose and Porous Graphite Phase Carbon Nitride/Porous Carbon Composites for Capturing and Determining of Organochlorine Pesticides from Water and Fruit Juice by Solid-Phase Microextraction

Herein, novel, loose, and porous graphite phase carbon nitride/porous carbon (g-C₃N₄@PC) composites were prepared by decorating cellulose nanocrystals (CNCs). The characterization results demonstrate that the as-prepared composites presented high specific surface areas, porous structures, and abundant chemical groups, with the modification of CNCs. In view of the unique advantages, g-C₃N₄@PC was used as the coating material for the solid-phase microextraction (SPME) of organochlorine pesticides (OCPs) in water and juice samples. The g-C₃N₄@PC-coated fibers showed better extraction efficiencies than commercial fibers (100/7 μm PDMS and PA) toward the OCPs, with the enrichment factors of the g-C₃N₄@PC-coated fibers 5-30 times higher than the latter. Using a gas chromatography-mass spectrometry (GC-MS) instrument, the g-C₃N₄@PC-coated fibers exhibited a gratifying analytical performance for determining low concentrations of OCPs, with a wide linear range (0.1-1600 ng L^-1 for water; 0.1-1000 ng L^-1 for juice), low limits of detection (0.0141-0.0942 ng L^-1 for water; 0.0245-0.0777 ng L^-1 for juice), and good reproducibility and repeatability in optimal conditions. The established method showed good sensitivity and recovery in the determination of OCPs in the water and fruit juice samples, which displayed broad prospects for analyzing organic pollutants from environmental samples.

Dispersive liquid-liquid microextraction method combined with sugaring-out homogeneous liquid-liquid extraction for the determination of some pesticides in molasses samples

In this study, a sensitive analytical method was developed to determine some pesticides (cyprodinil, trifloxystrobin, prometryn, propachlor, fenitrothion, chlorpyrifos, profenofos, and phosalone) in molasses samples. Pesticides were extracted from samples by dispersive liquid-liquid microextraction method combined with sugaring-out homogeneous liquid-liquid extraction and determined by gas chromatography-mass spectrometry analysis. In this method, pesticides in molasses samples were first extracted using a water-miscible solvent (acetonitrile) in the sugaring-out homogeneous liquid-liquid extraction stage. The sugar in the ratio of 84-88% naturally contained in the molasses sample enabled phase separation in the acetonitrile-water homogeneous mixture. Then acetonitrile phase containing pesticides was used as dispersing solvent in the second step of the process. Under the specified optimum conditions, the limit of detection was calculated between 0.8-6.1 ng/g and the limit of quantification was in the range of 2.5-20 ng/g. The relative standard deviation values of molasses samples containing 150 ng/g of each analyte were found to be lower than 4.9% intra-day and 5.6% for inter-day. This validated method has been successfully applied to different types of molasses.

Extraction and electrochemical sensing of pesticides in food and environmental samples by use of polydopamine-based materials

Polydopamine has high adsorption capacities for pollutants such as pesticides in food and environmental matrices. Consequently, it has found applications in some sorbent-based micro-extraction techniques such as solid phase micro-extraction and magnetic solid phase extraction. This paper gives a detailed review of the application of polydopamine-based adsorbents for the extraction of pesticides in food and environmental matrices using these techniques. The adhesive properties of polydopamine have made it to be a suitable material for the immobilisation of the components of electrochemical sensors used to detect pesticides in food and environmental matrices. This paper also gives a comprehensive review on the application of polydopamine in electrochemical sensors such as acetylcholinesterase sensors, molecularly imprinted sensors and aptasensors. The use of polydopamine-based adsorbents during the extraction and electrochemical sensing of pesticides in food and environmental matrices is not free of challenges. In this review, the challenges encountered during the use of polydopamine-based adsorbents are also discussed.

Biocompatible chitosan-zinc oxide nanocomposite based dispersive micro-solid phase extraction coupled with HPLC-UV for the determination of rosmarinic acid in the extracts of medical plants and water sample

In the present research, a procedure was described for the recovery of rosmarinic acid (RA) from medical extract samples using chitosan‑zinc oxide nanoparticles as a biocompatible nanocomposite (CS-ZnO-NC). The dispersive micro-solid phase extraction (D-μ-SPE) of RA from the medical extract samples was investigated by using the prepared biocompatible composite as a solid phase. The HPLC-UV method was used for measuring the extracted RA. The important variables (pH, biocompatible composite mass, contact time, and volume of eluent) associated with the extraction process were analyzed by the application of central composite design (CCD). The achieved optimum values for the mentioned variables were 7.0, 10 mg, 4 min, and 180 μL, respectively. The extraction recovery (99.68%) obtained from the predicted model was in agreement with the experimental data (98.22 ± 1.33%). In addition, under the obtained optimum conditions and over the concentration in the range of 2-3500 ng mL-1, a linear calibration curve was obtained with R2 > 0.993. The limit of detection (LOD) and quantification (LOQ) values were computed, and the obtained ranges were respectively from 0.060 to 0.089 ng mL-1 and 0.201 to 0.297 ng mL-1. In addition, the enrichment factors were obtained in the range of 93.7-110.5 with preconcentration factor of 83.3. Therefore, the D-μ-SPE-HPLC-UV method could be used for analyzing RA in the samples of the extracts obtained from the medical plants and water with the recovery values of the analyte in the range of 96.6%-105.4% and the precision with relative standard deviation <5.7%.

Air-assisted ionic liquid dispersive liquid-liquid microextraction based on solidification of the aqueous phase for the determination of triazole fungicides in water samples by high-performance liquid chromatography

A simple, rapid, and environmentally friendly approach was introduced to determine triazole fungicides in water samples by air-assisted ionic liquid dispersive liquid-liquid microextraction based on solidification of the aqueous phase using high-performance liquid chromatography-diode array detection. Ionic liquid was applied as the extraction solvent rather than a high-toxicity extraction solvent. The air-assisted dispersion method induced a trace amount of the ionic liquid to disperse as small droplets in the water sample, which significantly increased the contact area between the organic phase and the aqueous phase for the rapid transfer of target fungicides without using a dispersion solvent or auxiliary extraction devices. The solidification of the aqueous phase facilitated the collection of extraction solvent. The type of extraction solvent, the volume ratio of the extraction solvent to the water sample, the number of extraction cycles, the addition of NaCl, and pH values were evaluated. The recoveries were 72.65-100.13% with a relative standard deviation of 0.92% to 5.99%. The limits of quantification varied from 0.65 ng mL^-1 to 1.83 ng mL^-1. This approach can be used to determine fungicides in ground, river, and lake water samples.

Successive pH- and heat-induced homogenous liquid-liquid extraction

A simple and efficient analytical method known as pH- and heat-induced homogenous liquid-liquid extraction combined with high-performance liquid chromatography has been successfully developed for the extraction and determination of neonicotinoid pesticides in aqueous samples. In this method, a few mL of a water-miscible basic extraction solvent is mixed with a high volume of an aqueous phase containing the analytes and passed through a tube which a portion of the tube is filled with sodium carbonate as a separating agent. By passing the solution, salt is dissolved and the fine droplets of the extraction solvent are formed. The produced droplets go up through the remained solution and collect as a separated layer. In the following, the collected organic phase is removed and placed into a micro tube. Then it is heated in a water bath to form two phases. Several experimental parameters that influence extraction efficiency such as type and volume of extraction solvent, type of phase separation agent, temperature, and extraction time were investigated. Under the optimum conditions, the extraction recoveries and enrichment factors ranged between 51 and 81% and 680 and 1080, respectively. Calibration curves showed a high-level of linearity for all target analytes with coefficients of determination ranging between 0.997 and 0.999. The repeatability of the proposed method expressed as relative standard deviation varied between 3 and 5% (n=6, C=50μgL(-1)), and the detection limits were in the range of 0.52-1.0μgL(-1). Finally, the performance of the method was evaluated by analyzing the selected pesticides in different fruit juice and vegetable samples.

Preparation of porous aromatic framework/ionic liquid hybrid composite coated solid-phase microextraction fibers and their application in the determination of organochlorine pesticides combined with GC-ECD detection

Novel porous aromatic framework/ionic liquid hybrid composite coated SPME fibers were prepared for the preconcentration of OCPs coupled with GC-ECD.

Use of magnetic effervescent tablet-assisted ionic liquid dispersive liquid-liquid microextraction to extract fungicides from environmental waters with the aid of experimental design methodology

In this work, a novel effervescence-assisted microextraction technique was proposed for the detection of four fungicides. This method combines ionic liquid-based dispersive liquid-liquid microextraction with the magnetic retrieval of the extractant. A magnetic effervescent tablet composed of Fe3O4 magnetic nanoparticles, sodium carbonate, sodium dihydrogen phosphate and 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonimide) was used for extractant dispersion and retrieval. The main factors affecting the extraction efficiency were screened by a Plackett-Burman design and optimized by a central composite design. Under the optimum conditions, good linearity was obtained for all analytes in pure water model and real water samples. Just for the pure water, the recoveries were between 84.6% and 112.8%, the limits of detection were between 0.02 and 0.10 μg L(-1) and the intra-day precision and inter-day precision both are lower than 4.9%. This optimized method was successfully applied in the analysis of four fungicides (azoxystrobin, triazolone, cyprodinil, trifloxystrobin) in environmental water samples and the recoveries ranged between 70.7% and 105%. The procedure promising to be a time-saving, environmentally friendly, and efficient field sampling technique.

Graphene oxide reinforced polymeric ionic liquid monolith solid-phase microextraction sorbent for high-performance liquid chromatography analysis of phenolic compounds in aqueous environmental samples

A graphene oxide reinforced polymeric ionic liquids monolith was obtained by copolymerization of graphene oxide doped 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate monomer and 1,6-di-(3-vinylimidazolium) hexane bihexafluorophosphate cross-linking agent. Coupled to high-performance liquid chromatography, the monolith was used as a solid-phase microextraction sorbent to analyze several phenolic compounds in aqueous samples. Under the optimized extraction and desorption conditions, linear ranges were 5-400 μg/L for 3-nitrophenol, 2-nitrophenol, and 2,5-dichlorophenol and 2-400 μg/L for 4-chlorophenol, 2-methylphenol, and 2,4,6-trichlorophenol (R(2) = 0.9973-0.9988). The limits of detection were 0.5 μg/L for 3-nitrophenol and 2-nitrophenol and 0.2 μg/L for the rest of the analytes. The proposed method was used to determine target analytes in groundwater from an industrial park and river water. None of the analytes was detected. Relative recoveries were in the range of 75.5-113%.