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Determination of Target Pesticide Residues in Tropical Fruits Employing Matrix ...
Freitas,Silvia S.; Serafim,Felipe A. T.; Lanças,Fernando M.A simple method based on matrix solid-phase dispersion (MSPD) extraction and gas chromatography with electron-capture detection (GC-ECD) is employed to determine pesticide residues in the following tropical fruits: banana, mango, melon, papaya and pineapple. In the MSPD proposed method, C18, silica gel and ethyl acetate presented the best results in the extraction, clean-up and elution steps, respectively. Spik...
Evaluation of a simple hyphenated system for flow injection solid-phase pre-con...
Assunção,Nilson A.; Miranda,Carlos E. S.; Lanças,Fernando M.; Rosias,Maria Fernanda G. G.; Carrilho,EmanuelIn this work, the development and evaluation of a hyphenated flow injection-capillary electrophoresis system with on-line pre-concentration is described. Preliminary tests were performed to investigate the influence of flow rates over the analytical signals. Results revealed losses in terms of sensitivity of the FIA-CE system when compared to the conventional CE system. To overcome signal decrease and to make t...
Development of instrumentation for amperometric and coulometric detection using...
Coutinho,Cláudia F. B.; Coutinho,Lincoln F. M.; Lanças,Fernando M.; Câmara,Carlos A. P.; Nixdorf,Suzana L.; Mazo,Luiz H.In this work it is presented the development of a simple, portable and inexpensive instrumentation for amperometric and coulometric detection in different analytical instrumentation systems utilizing ultramicroelectrodes. The software, developed in LabVIEW 7.1TM, is capable to carry out three main detection techniques (amperometric, pulsed amperometric and coulometric detection) and a voltammetric technique (cy...
Solid-phase extraction of nitro-PAH from aquatic samples and its separation by ...
Toledo,Marcelo; Lanças,Fernando M.; Carrilho,EmanuelIn this work, an analytical methodology to extract 1-nitronaphthalene, 2-nitrofluorene, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene aquatic samples is proposed. Capillary liquid chromatography with on-column UV detection (µLC-UV) was employed to separate and quantitate all five nitrated polycyclic aromatic hydrocarbons (nitro-PAH) extracted from water samples. Two different extraction techniques w...
Hydrolysis of corn oil using subcritical water
Pinto,Jair Sebastião S.; Lanças,Fernando M.This work presents the results of a study on the use of subcritical water as both solvent and reactant for the hydrolysis of corn oil without the use of acids or alkalis at temperatures of 150-280 °C. Corn oil hydrolysis leads to the formation of its respective fatty acids with the same efficiency of conventional methods. Fatty acids form an important group of products, which are used in a range of applications...
Fluidos supercríticos em química analítica. III.: aplicações
Carrilho,Emanuel; Tavares,Maria Cecília H.; Lanças,Fernando M.The first two papers in this series described the basic theory involved in supercritical fluid chromatography (SFC), how the technique evolved from gas and liquid chromatography and how the instrumentation was developed. Over the last two years, a commercial, dedicated packed-column SFC/MS instrument appeared on the market. The SFC continues to grow in use, with fundamental developments, coupled with a steady r...
Variabilidade sazonal de constituintes químicos (triterpenos, flavonóides e pol...
Yariwake,Janete H.; Lanças,Fernando M.; Cappelaro,Esmeraldo A.; Vasconcelos,Eliane C. de; Tiberti,Luciana A.; Pereira,Ana M.S.; Franca,Suzelei de C.Estudou-se a variabilidade química sazonal em Maytenus aquifolium Mart. (Celastraceae), conhecida como "espinheira santa", em exemplares cultivados em Ribeirão Preto, SP, através da análise das substâncias presentes nas folhas, ao longo das quatro estações em dois anos. O teor de fenóis totais variou de 21,96 a 45,92 mg / g (expresso em mg ácido tânico / g folhas secas), de 55,88 a 93,20 mg triterpenos totais /...
Análise de fármacos em material biológico: acoplamento microextração em fase só...
Queiroz,Maria Eugênia C.; Lanças,Fernando M.A new solid phase microextraction (SPME) system, known as in-tube SPME, was recently developed using an open tubular fused-silica capilary column, instead of an SPME fiber, as the SPME device. On-line in-tube SPME is usually used in combination with high performance liquid chromatography. Drugs in biological samples are directly extracted and concentrated in the stationary phase of capillary columns by repeated...
Development and validation of a multi-residue analytical methodology to determi...
Brondi,Silvia H. G.; Lanças,Fernando M.In the present work an analytical methodology is described to determine the presence of multi-residues of selected pesticides used in sugar-cane cultures (tebuthiuron, hexazinone, diuron, 2,4-D and ametrine), in source of drinking water. The analytes were isolated from the water matrix through the following techniques: liquid-liquid extraction (LLE) using dichloromethane as solvent; solid phase extraction (SPE)...
Solid-Phase purification of deoxyguanosine-benzo[a]pyrene diol epoxide adducts ...
Formenton-Catai,Ana Paula; Machado,Rosecler Pereira; Lanças,Fernando M.; Carrilho,EmanuelHidrocarbonetos polinucleares aromáticos são compostos largamente presentes no meio ambiente e são reconhecidamente considerados compostos carcinogênicos e/ou mutagênicos. Tais substâncias quando presentes em organismos são metabolizados e podem se ligar ao DNA formando adutos. Tais adutos podem induzir erros de replicação os quais podem causar um tumor carcinogênico ou uma mutação genética. Conseqüentemente, a...