Assessing organophosphorus and carbamate pesticides in maize samples using MIP extraction and PSI-MS analyzes.

The indiscriminate utilization of agrochemicals causes environmental and animal life impacts. In this regard, methodologies have been developed to offer efficiency and quickness for agrochemicals detection. Due to their selectivity and molecular recognition sites, Molecular Imprinted Polymer (MIPs) have been widely employed in some areas, including biotechnology, waste analyses, foodstuff, biological fluids, and others. This work proposed developing a method to determine aminocarb, pirimicarb, dimethoate, omethoate, pyridaphenthion, and fenitrothion pesticides using molecularly imprinted polymer combined with solid-phase extraction (MIP-SPE) for clean-up and paper spray ionization mass spectrometry for their analysis. Extractions analysis for Aminocarb, Pirimicarb, and Omethoate using MIP-SPE showed better performance when compared with MIP and NIP. The R 2 values were found with R 2 > 0.98 for all pesticides, and LODs and LOQs values were 50 and 100 µg kg-1, respectively. The precision and accuracy were assessed at three concentration levels-low, medium, and high. The precision values (interday and intraday) were below 10%, and the variation of recovery was between 80 and 120% for all pesticides. Therefore, it was possible to verify the presence of two carbamates and five organophosphorus without the necessity of preconcentration samples with precision and good recovery. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05464-7.

Change in the Chemical Profile of Mangifera indica Leaves after their Metabolism in the Tropidacris collaris Grasshopper.

This present work addresses research on the discovery of new compounds from natural sources. It is based on a study of Mangifera indica leaf metabolism by the Tropidacris collaris grasshopper. We found that the grasshopper hydrolyzed the flavonoid isoquercitrin to quercetin when the O-glycosidic bond was broken and sugar released as a probable energy source for the insect. There was not, however, hydrolysis of the major compound in the leaves, mangiferin, which contains the C-glycosidic bond. All compounds were isolated and their chemical structure determined by UV, IR, MS, 1H and 13C NMR.

Metabolism by grasshoppers of volatile chemical constituents from Mangifera indica and Solanum paniculatum leaves.

The chemical volatiles from plant leaves and their biological activities have been extensively studied. However, no studies have addressed plant-chemical volatiles after undergoing the digestive process in host insects. Here we describe for the first time chemical profiles of volatile constituents from Solanum paniculatum and Mangifera indica leaves metabolized by grasshoppers. Both profiles were qualitatively and quantitatively different from the profiles of non-metabolized leaves. The amount of nerolidol, the major constituent of S. paniculatum leaves, decreased and other sesquiterpenes, such as spathulenol, were formed during the digestive process of the grasshopper Chromacris speciosa. In M. indica, the presence of phenylpropanoids was observed (dillapiole, Z-asarone, E-asarone and γ-asarone) in the leaves metabolized by the grasshopper Tropidacris collaris, but these compounds were not found in the non-metabolized leaves.