Análise dos produtos de degradação do esfenvalerato por SBSE/CLAE-UV/DAD utilizando planejamento fatorial fracionário

A simple procedure based on stir bar sorptive extraction and high-performance liquid chromatography-ultraviolet/photodiode array detection (SBSE/LC-UV/PAD) to determine intermediates and by-products of esfenvalerate is described. The influence of organic modifier, ionic strength, extraction time, temperature and pH were simultaneously evaluated by using a factorial experimental design. The utilization of different organic solvents and desorption times were also investigated to establish the optimal conditions for SBSE liquid desorption. Among the ten different peaks (intermediates and by-products) detected after degradation of esfenvalerate, eight (including 3-phenoxybenzoic acid and 3-phenoxybenzaldehyde) were successfully extracted by SBSE under the optimized conditions.

Extração sortiva em barra de agitação para análise de fármacos em fluidos biológicos

A novel solventless sample preparation, stir-bar sorptive extraction (SBSE), for extraction, and sample enrichment of organic compounds from biological fluids, is described in this manuscript from principle to applications. The SBSE is based on sorptive extraction, whereby the compounds are extracted into a polymer coating, polydimethylsiloxane (PDMS), on a magnetic stirring rod. The extraction is controlled by the partitioning coefficient of drugs between the PDMS and sample matrix, and upon the sample-extraction medium phase ratio. The SBSE technique has been applied successfully, with high sensitivities, to biomedical analysis of volatiles and for semi-volatiles drugs from biological sample, including urine, plasma, and saliva. SBSE combined with in situ derivatization, drugs quite more polar (e.g. metabolites) also can be analyzed.

Principais técnicas de preparo de amostra para a determinação de resíduos de agrotóxicos em água por cromatografia líquida com detecção por arranjo de diodos e por espectrometria de massas

The determination of pesticide residues in water samples by Liquid Chromatography require sample preparation for extraction and enrichment of the analytes with the minimization of interferences to achieve adequate detection limits. The Solid Phase Extraction (SPE), Solid Phase Microextraction (SPME), Stir Bar Sorptive Extraction (SBSE) and Dispersive Liquid-Liquid Microextraction (DLLME) techniques have been widely used for extraction of pesticides in water. In this review, the principles of these sample preparation techniques associated with the analysis by Liquid Chromatography with Diode Array Detection (LC-DAD) or Mass Spectrometry (LC-MS) are described and an overview of several applications were presented and discussed.