Study of insecticide translocation in coconut palm trees after using pressurized endotherapy.

Alternative techniques for applying agricultural products, such as pressurized endotherapy, have shown promise in pest and disease control in coconut palms (Cocos nucifera Linn.). In this work, azadirachtin and abamectin were applied by pressurized endotherapy to control Brassolis sophorae. Twelve different treatments were carried out, and in all of them, at least one plant had the larvae completely dead four and five days after endotherapeutic applications, and all the others died within the next few hours. Leaf and fruit analyses were performed to determine the concentration over time. High concentrations of abamectin were observed after 15 and 30 days on leaves when applied in larger volumes. In fruits, no residue was found regardless of the applied concentration. Analytical methods were developed and validated for leaves and fruits to analyze insecticide residues using LC-MS/MS and modified QuEChERS acetate according to SANTE/11813/2017 guidelines. The insecticide translocation tests in the leaves and the high mortality of insects showed that pressurized endotherapy is a technique to be considered for future studies in controlling B. sophorae in coconut palm trees.

Characterization of the lipid profile from coconut (Cocos nucifera L.) oil of different varieties by electrospray ionization mass spectrometry associated with principal component analysis and independent component analysis.

Coconut oil (CO) from fifteen different varieties of coconuts (Cocos nucifera L.) and one CO processed on an industrial scale were analyzed by electrospray ionization mass spectrometry (ESI-MS) and the data processed using the chemometric tools principal component analysis and independent component analysis. ESI-MS fingerprinting of lipid compounds showed predominance of diacylglycerols and triacylglycerols, as confirmed by high-resolution MS measurements. Chemometric processing of the ESI-MS data differentiated the coconut oil samples, showing that different coconut varieties/cultivars produce oils with distinguishable abundances of lipidic compounds. Thus ESI-MS analysis followed by data treatment using chemometric tools offers a tool able to classify the industrial coconut oils in a fast, simple and effective way, as well as serving as a potential method to identify the coconut varieties by the CO origin, and the occurrence of any adulteration. The procedure may also be applied for quality control of the industrial processes.

Determination of pesticides in coconut (Cocos nucifera Linn.) water and pulp using modified QuEChERS and LC-MS/MS.

The use of pesticides is directly linked to improvements in productivity and to the preservation of coconut palms. However pesticide analysis is necessary to determine whether pesticide residues in the food products containing coconut are within the maximum residue limits (MRLs), ensuring the quality of these products. This work aimed to develop a method for multiresidue determination of ten pesticides in coconut water and pulp using QuEChERS and LC-MS/MS. The method was effective in terms of selectivity, linearity, matrix effect, accuracy and precision, providing LOD of 3µgkg(-1), LOQ of 10µgkg(-1) and recoveries between 70 and 120% with RSD lower than 20%. The developed method was applied to 36 samples in which residues of carbendazim, carbofuran, cyproconazole and thiabendazole were found below the LOQ in coconut water and pulp.

MSPD sample preparation approach for reversed-phase liquid chromatographic analysis of pesticide residues in stem of coconut palm.

A method was developed using matrix solid-phase dispersion, together with liquid chromatography with ultraviolet diode array detector for determination of carbofuran, difenoconazole, ß-cyfluthrin, spirodiclofen and thiophanate-methyl in stem of coconut palm. The best results were obtained using 2.0 g of stem, 1.6 g of Florisil as sorbent and cyclohexane:acetone mixture (4:1). The method was validated using stem samples spiked with pesticides at four concentration levels (0.05-2.0 µg/g). Average recoveries ranged from 70 % to 114.3 %, with relative standard deviations between 1.2 % and 19.2 %. Detection and quantification limits were in the ranges 0.02-0.03 and 0.05-0.1 µg/g, respectively.

Investigating the potential of metal-organic framework material as an adsorbent for matrix solid-phase dispersion extraction of pesticides during analysis of dehydrated Hyptis pectinata medicinal plant by GC/MS.

Metal-organic frameworks aluminum terephthalate MIL-53 and Cu-benzene-1,3,5-tricarboxylate (BTC) were tested for extraction of pyrimethanil, ametryn, dichlofluanid, tetraconazole, flumetralin, kresoximmethyl, and tebuconazole from the medicinal plant Hyptis pectinata, with analysis using GC/MS in the selected ion monitoring mode. Experiments carried out at different fortification levels (0.1, 0.5, and 1.0 microg/g) resulted in recoveries in the range 61 to 107% with RSD values between 3 and 12% for the metal-organic framework materials. Detection and quantification limits ranged from 0.02 to 0.07 and 0.05 to 0.1 microg/g, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.04-20.0 microg/g), with correlation coefficients ranging from 0.9987 to 0.9998. Comparison of MIL-53 and Cu-BTC with C18-bonded silica showed good performance of the MIL-53 metal-organic framework as a sorbent for the pesticides tested.