Este estudo comparou quatro procedimentos de extração para a determinação simultânea das micotoxinas citrinina e ocratoxina A em amostras de arroz. Os procedimentos de Soares e Rodriguez-Amaya, Tanaka e os métodos de extração QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) e por ultrassom foram comparados em termos de geração de resíduos, limite de detecção, limite de quantificação e ...

QuEChERS sample preparation was optimized using solvent extraction with acetonitrile and dispersive-solid phase extraction with primary and secondary amine sorbents, and validated for high-performance liquid chromatographic determination of nine steroids commonly used to adulterate herbal medicines: such as triamcinolone, prednisolone, hydrocortisone, methylprednisolone, betamethasone, dexameth...

A higher monitoring rate is highly desirable in the labs, but this goal is typically limited by sample throughput. In this study, we sought to assess the real-world applicability of fast, low-pressure GC-time-of-flight MS (LP-GC/TOFMS) for the identification and quantification of 150 pesticides in tomato, strawberry, potato, orange, and lettuce samples. Buffered and unbuffered versions of QuECh...

Ergovaline is an ergot alkaloid produced by the symbiotic endophyte Epichloë coenophiala, which can colonize varieties of the cool-season grass tall fescue (Festuca arundinacea). It is the principle toxicant responsible for the vasoconstrictive and reproductive sequelae seen in "fescue toxicosis" in livestock which consume forage exceeding the threshold of toxicity established for this compound...

the most used quechers and gas chromatography methods were performed, to evaluate the presence of organochlorines, organophosphate, polychlorinated biphenyl and chlorobenzenes in water and in fish. according to the standard iso iec 17025, a recovery rate obtained ranged from 70 to 120% assessing the reliability of analysis results. the exceed rate in fish of malathion is 22.2, and 5.2 ppm in sa...

wastewater contains a variety of chemical substances owing to the different sources that contribute to affluent into sewage treatment plants. raw and wastewater samples were obtained from the surface of the water bodies at depths of 50 and 100 metres but at different locations in each sampling site. the water samples were subjected to extraction of polychlorinated biphenyls (pcbs) using quecher...

A fast method of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed for the analysis of eleven UV ink photoinitiators in packaged food. Chromatographic separation was achieved in a pentafluorophenylpropyl (PFPP) column at 5°C and acetonitrile:25 mM formic acid-ammonium formate (pH 2.7) in gradient elution. To reduce sample treatment, a QuEChERS (quick, easy, chea...

This article describes the comparison of different versions of an easy, rapid and low-cost sample preparation approach for the determination of pesticide residues in fruits and vegetables by concurrent use of gas and liquid chromatography (GC and LC) coupled to mass spectrometry (MS) for detection. The sample preparation approach is known as QuEChERS, which stands for "quick, easy, cheap, effec...

This application note describes a simple and rapid extraction procedure for pesticide residues in lemon essential oils. The method uses Agilent Bond Elut QuEChERS extraction and modified dispersive SPE coupled with GC/MS. Author Limian Zhao and Joan Stevens Agilent Technologies, Inc. 2850 Centerville Road Wilmington, DE 19808 USA Application Note

a fast and simple modified quechers (quick, easy, cheap, rugged and safe) extraction method based on spiked calibration curves and direct sample introduction was developed for determination of benzo[a]pyrene (bap) in bread by gas chromatography-mass spectrometry single quadrupole selected ion monitoring (gc/ms-sq-sim). sample preparation includes extraction of bap into acetone followed by clean...