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Scientific Reports May 2024In this study, a sensitive and selective fluorescent chemosensor was developed for the determination of pirimicarb pesticide by adopting the surface molecular imprinting...
In this study, a sensitive and selective fluorescent chemosensor was developed for the determination of pirimicarb pesticide by adopting the surface molecular imprinting approach. The magnetic molecularly imprinted polymer (MIP) nanocomposite was prepared using pirimicarb as the template molecule, CuFeO nanoparticles, and graphene quantum dots as a fluorophore (MIP-CuFeO/GQDs). It was then characterized using X-ray diffraction (XRD) technique, Fourier transforms infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The response surface methodology (RSM) was also employed to optimize and estimate the effective parameters of pirimicarb adsorption by this polymer. According to the experimental results, the average particle size and imprinting factor (IF) of this polymer are 53.61 nm and 2.48, respectively. Moreover, this polymer has an excellent ability to adsorb pirimicarb with a removal percentage of 99.92 at pH = 7.54, initial pirimicarb concentration = 10.17 mg/L, polymer dosage = 840 mg/L, and contact time = 6.15 min. The detection of pirimicarb was performed by fluorescence spectroscopy at a concentration range of 0-50 mg/L, and a sensitivity of 15.808 a.u/mg and a limit of detection of 1.79 mg/L were obtained. Real samples with RSD less than 2 were measured using this chemosensor. Besides, the proposed chemosensor demonstrated remarkable selectivity by checking some other insecticides with similar and different molecular structures to pirimicarb, such as diazinon, deltamethrin, and chlorpyrifos.
Topics: Pesticides; Carbamates; Quantum Dots; Molecularly Imprinted Polymers; Polymers; Spectrometry, Fluorescence; Graphite; Molecular Imprinting; Adsorption; Limit of Detection; Spectroscopy, Fourier Transform Infrared; Nanocomposites; Pyrimidines
PubMed: 38704412
DOI: 10.1038/s41598-024-60748-6 -
Insects Sep 2023The invasive apricot aphid ( Matsumura) is an important pest of apricot trees ( L.). In the presented study, laboratory bioassays using treated leaf disks of apricot...
The invasive apricot aphid ( Matsumura) is an important pest of apricot trees ( L.). In the presented study, laboratory bioassays using treated leaf disks of apricot were conducted to test the efficacy of twelve insecticides according to the maximum field dose. Additionally, dose-response curves were established for selected insecticides, and the effects on colony development were evaluated. Furthermore, a field trial was conducted to investigate the effectiveness of commonly used insecticides in apricot cultivation. The dose-response curves showed LC values ranging from 0.08 mg/L for flupyradifurone, 0.15 mg/L for acetamiprid, 0.70 mg/L for etofenprox, 1.89 mg/L for sulfoxaflor, 2.64 mg/L for pirimicarb, 3.97 mg/L for deltamethrin, up to 6.79 mg/L for tau-fluvalinate. These aforementioned insecticides resulted in mortality rates ranging from 95 to 100% at the field dose. Azadirachtin, flonicamid, and pyrethrins showed mortality rates of 27 to 45%. Spirotetramat reduced the colony development and decreased the number of infested shoots by 86%. Spinosad, which is not recommended against aphids, showed minimal impact; reducing the number of exuviae in nymphs in the colony development bioassay. It can be concluded that the majority of the tested insecticides are effective against .
PubMed: 37754715
DOI: 10.3390/insects14090746 -
Foods (Basel, Switzerland) Aug 2023In this study, a new approach to pesticide permeation through the apple peel into the pulp is discussed. The tested compounds can be classified, based on mode of action,...
In this study, a new approach to pesticide permeation through the apple peel into the pulp is discussed. The tested compounds can be classified, based on mode of action, as systemic (boscalid, cyprodinil, pirimicarb, propiconazole and tebuconazole) or contact (captan, cypermethrin and fludioxonil) pesticides. The barrier effect was assessed using a Franz flow-type vertical diffusion cell system. A residue analysis was performed using a modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) extraction method coupled to gas chromatography with tandem mass spectrometry (GC-MS/MS). The limits of detection (LODs) ranged between 2.6 µg kg (pirimicarb) and 17 µg kg (captan), with the coefficient of variability (CV) lower than 6%, while recoveries ranged from 85% (boscalid) to 112% (captan) at 0.1 and 1 mg kg spiked levels. The highest peel penetration was observed for pirimicarb, captan and cyprodinil, with cumulative permeations of 90, 19 and 17 µg cm, respectively. The total absorption was in the range from 0.32% (tebuconazole) to 32% (pirimicarb). Only cypermethrin was not quantitatively detected in the pulp, and its use can be recommended in crop protection techniques. The obtained results indicate that molecular weight, octanol-water partition coefficient and water solubility are important parameters determining the process of pesticide absorption.
PubMed: 37685153
DOI: 10.3390/foods12173220