Azadirachtin-A from Impacts Multiple Biological Targets in Cotton Bollworm .

Azadirachtin-A (AzaA) from the Indian neem tree () has insecticidal properties; however, its molecular mechanism remains elusive. The "targeted and nontargeted proteomic profiling", metabolomics, matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) imaging, gene expression, and in silico analysis provided clues about its action on . Fourth instar larvae fed on AzaA-based diet (AzaD) suffered from significant mortality, growth retardation, reduced larval mass, complications in molting, and prolonged development.

Review of analytical methods for the determination of pesticide residues in grapes.

This review presents an overview of analytical methods for the analysis of pesticide residues in grapes and by-products in the last decade. The most widely used detection technique for the determination of pesticides in grapes is mass spectrometry combined with gas and/or liquid chromatography. In general, multi-residue methods with selective sample treatment methodologies have been developed for this purpose.

Proficiency test on the determination of pesticide residues in grapes with multi-residue methods.

This manuscript presents the results of the International Measurement Evaluation Programme 37 (IMEP-37) study, a proficiency test (PT) which was organised to assess the world-wide performance of food control laboratories on the determination of pesticide residues in grapes. This PT supports the implementation of Regulation (EC) No 396/2005 on maximum residue levels of pesticides in or on food and feed of plant and animal origin. Eighty-one participants reported results, forty from EU Member States and forty-one from outside the EU.

Development of a new cucumber reference material for pesticide residue analysis: feasibility study for material processing, homogeneity and stability assessment.

The feasibility of the production of a reference material for pesticide residue analysis in a cucumber matrix was investigated. Cucumber was spiked at 0.075 mg/kg with each of the 15 selected pesticides (acetamiprid, azoxystrobin, carbendazim, chlorpyrifos, cypermethrin, diazinon, (α + β)-endosulfan, fenitrothion, imazalil, imidacloprid, iprodione, malathion, methomyl, tebuconazole and thiabendazole) respectively.

Analytical study of azadirachtin and 3-tigloylazadirachtol residues in foliage and phloem of hardwood tree species by liquid chromatography-electrospray mass spectrometry.

A rapid and sensitive LC-ESI-MS method has been developed and validated for the quantitation of azadirachtin and 3-tigloylazadirachtol in deciduous tree matrices. The method involves automated extraction and simultaneous cleanup using an accelerated solvent technique with the matrix dispersed in solid phase over a layer of primary-secondary amine silica. The limits of quantification were 0.

Foliar residue dynamics of azadirachtins following direct stem injection into white and green ash trees for control of emerald ash borer.

Background: Azadirachtins are natural insecticides derived from the neem tree. The emerald ash borer (EAB) is an exotic invasive insect pest that infests various ash tree species and has the potential for significant economic, aesthetic and ecological impacts throughout North America. The initial translocation and foliar residue dynamics of azadirachtins were examined following direct injection into white and green ash trees growing in urban scenarios as a potential control for EAB.

Environmental safety to decomposer invertebrates of azadirachtin (neem) as a systemic insecticide in trees to control emerald ash borer.

The non-target effects of an azadirachtin-based systemic insecticide used for control of wood-boring insect pests in trees were assessed on litter-dwelling earthworms, leaf-shredding aquatic insects, and microbial communities in terrestrial and aquatic microcosms. The insecticide was injected into the trunks of ash trees at a rate of 0.2 gazadirachtin cm(-1) tree diameter in early summer.

Comparison between triple quadrupole, time of flight and hybrid quadrupole time of flight analysers coupled to liquid chromatography for the detection of anabolic steroids in doping control analysis.

Triple quadrupole (QqQ), time of flight (TOF) and quadrupole-time of flight (QTOF) analysers have been compared for the detection of anabolic steroids in human urine. Ten anabolic steroids were selected as model compounds based on their ionization and the presence of endogenous interferences. Both qualitative and quantitative analyses were evaluated.

Quantification, confirmation and screening capability of UHPLC coupled to triple quadrupole and hybrid quadrupole time-of-flight mass spectrometry in pesticide residue analysis.

The potential of three mass spectrometry (MS) analyzers (triple quadrupole, QqQ; time of flight, TOF; and quadrupole time of flight, QTOF) has been investigated and compared for quantification, confirmation and screening purposes in pesticide residue analysis of fruit and vegetable samples. For this purpose, analytical methodology for multiresidue determination of 11 pesticides, taken as a model, has been developed and validated in nine food matrices for the three mass analyzers coupled to ultra high pressure liquid chromatography. In all cases, limits of quantification around 0.

Use of ultra-high-pressure liquid chromatography-quadrupole time-of-flight MS to discover the presence of pesticide metabolites in food samples.

In this paper we illustrate the use of two different methodologies to investigate the presence of pesticide metabolites in parent pesticide-positive food samples, using ultra-high-pressure liquid chromatography coupled to hybrid quadrupole time-of-flight (UHPLC-QTOF) mass spectrometry. First, a common fragmentation pathway between the parent pesticide and its metabolites has been considered to search for metabolites in two positive market samples (imazalil in lemon, chlorpyrifos in grape). Secondly, olive oil samples from field residue trials were used for automated application of comparative software (MetaboLynx), which was used with treated and untreated samples to search for expected and unexpected metabolites of phosmet.

Detection and structural investigation of metabolites of stanozolol in human urine by liquid chromatography tandem mass spectrometry.

The applicability of LC-MS/MS in precursor ion scan mode for the detection of urinary stanozolol metabolites has been studied. The product ion at m/z 81 has been selected as specific for stanozolol metabolites without a modification in A- or N-rings and the product ions at m/z 97 and 145 for the metabolites hydroxylated in the N-ring and 4-hydroxy-stanozolol metabolites, respectively. Under these conditions, the parent drug and up to 15 metabolites were found in a positive doping test sample.

Collision-induced dissociation of 3-keto anabolic steroids and related compounds after electrospray ionization. Considerations for structural elucidation.

The collision-induced dissociation of forty-one 3-keto anabolic steroids and related compounds has been studied using both triple quadrupole (QqQ) and hybrid quadrupole-time of flight (QTOF) instruments. Due to the complexity of the product ion spectra of these analytes, which generate a large number of ions, only two specific regions were studied in depth: the product ions near the precursor ion (m/z > or =M-100) and the most abundant product ions at a collision energy of 30 eV. Accurate mass measurements were used in order to obtain an unequivocal assignment of the empirical formula and the origin of each selected product ion.

Use of liquid chromatography coupled to quadrupole time-of-flight mass spectrometry to investigate pesticide residues in fruits.

In this paper, the potential of coupling liquid chromatography with hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF) for the determination of pesticides in a variety of fruit samples (orange peel and flesh, banana skin and flesh, strawberry and pear) has been explored. The quantitative application at residue levels has been proven for two insecticides (buprofezin and hexythiazox), which were satisfactorily determined at three concentration levels, 0.1, 1, and 5 mg/kg, obtaining a suitable linearity range (correlation coefficient>0.

Analytical study of trichlorfon residues in Kaki fruit and cauliflower samples by liquid chromatography-electrospray tandem mass spectrometry.

A detailed analytical study on trichlorfon residues in selected vegetables samples has been carried out, focused on the reliable quantification and confirmation of this compound, and on stability of residues under storage. As a consequence, a rapid and sensitive LC-ESI-MS/MS method has been developed for the determination of residues of this insecticide in kaki fruit (flesh and peel) and cauliflower samples. Extraction was performed with acetonitrile using a high-speed blender.

Evaluation of different quantitative approaches for the determination of noneasily ionizable molecules by different atmospheric pressure interfaces used in liquid chromatography tandem mass spectrometry: abamectin as case of study.

The liquid chromatography tandem mass spectroscopy residue determination of compounds without any acidic or basic centers such as abamectin has been investigated. Several approaches regarding the interface used and adduct formation have been compared. The low acidity of the hydroxyl groups only made deprotonation feasible using the atmospheric pressure chemical ionization (APCI) interface.

Rapid determination of fosetyl-aluminum residues in lettuce by liquid chromatography/electrospray tandem mass spectrometry.

This paper describes a new method for the sensitive and selective determination of fosetyl-aluminum (Al) residues in vegetable samples. The method involves extraction with water by using a high-speed blender and subsequent injection of the 5-fold diluted extract into the liquid chromatograph. Fosetyl-Al is determined by liquid chromatography with electrospray tandem mass spectrometry after the addition of tetrabutylammonium acetate as the ion-pairing reagent.

Direct determination of paclobutrazol residues in pear samples by liquid chromatography-electrospray tandem mass spectrometry.

A rapid and sensitive liquid chromatography/electrospray ionization/tandem mass spectrometry (LC-ESI-MS-MS) method has been developed for the determination of the plant growth regulator paclobutrazol in pear samples. Extraction was performed with methanol by using a high-speed blender Ultra-Turrax, and 10 microL of pear extract was directly injected in the LC-ESI-MS-MS system without any previous sample treatment. The highest sensitivity of the method was achieved under MS-MS conditions obtaining a limit of detection of 0.