Sandra R. Rissato

Determination of 2,4-D and Dicamba in food crops by MEKC

SummaryThe determination of 2,4-D (2,4-dichlorophenoxyacetic acid) and Dicamba (2-methoxy-3,6-dichlorobenzoic acid) residues in sugar cane, rice and corn was performed by a supercritical fluid extraction (SFE) method using CO2/acetone as extraction mix and an SFE apparatus developed in our laboratory. The extracts were cleaned up after extraction by both liquid-liquid partition and a Florisil column. Micellar electrokinetic capillary chromatography (MEKC) coupled with ultraviolet on-column detection was used for the analysis of these pesticides. The detection limits were improved by the preparation of a special detection cell with an increased pathlength that gave detection limits of ca. 0.6 pg for 2,4-D and Dicamba. Our results demonstrated that capillary electrophoresis can be a powerful new analytical tool for pesticide residue analysis.

Off-line SFE-CZE analysis of carbamates residues in tobacco samples

SummaryDetermination of carbamate residues in tobacco samples was carried out by solid-liquid extraction (SLE) and supercritical-fluid extraction (SFE) methods, both developed for this purpose. The clean-up step was carried out on SPE-Florisil cartridges and the extracts analysed by capillary zone electrophoresis (CZE) with UV detection.The results were compared and SFE using CO2-acetone showed the best results in terms of recovery and generally higher extraction power. SFE in conjunction with CZE proved suitable for carbamate residue analysis in real tobacco samples.

Supercritical fluid extraction of chlorothalonil residues from apples

SummaryA new method for the extraction of Chlorothalonil residues from apples using supercritical CO2 as the extracting fluid is described. The supercritical fluid extraction results were compared with those obtained by solid-liquid extraction. The results showed that SFE is faster and more selective with better recovery and higher selectivity.

Off‐Line SFE‐MEKC Determination of Diuron in Sugar Cane and Orange Samples

University of Sao Paulo Inst. of Chem. of Sao Carlos, P.O. Box 780, 13560-970, Sao Carlos (SP)

Supercritical fluid extraction of flumetralin in tobacco

SummaryThis work evaluates the level of Flumetralin residues in real tobacco samples. Conventional extraction methods were compared with SFE methods in both static and dynamic modes using CO2 and CO2 with modifier. Additionally, in the dynamic SFE mode, different collection approaches, such as collection at room temperature without solvent, collection at room temperature in the presence of solvent (hexane) and collection in an ice bath, without solvent, were studied. SFE showed itself to be a promising extraction technique for pesticide residues in tobacco samples.

UPGRADING OF SUGAR CANE BAGASSE BY THERMAL PROCESSES.2. CATALYTIC EFFECTS OF INORGANIC SALTS ON THE LIQUEFACTION OF BAGASSE WITH MONOETHANOLAMINE

Abstract Sugar cane bagasse was hydrogenated with monoethanolamine at 370°C under 2000psi of H2 for 1h using different catalysts (metallic and zeolitic). The qualitative and quantitative aspects are compared through conversion yields and thermogravimetric and elemental analysis of the liquefield products.

UPGRADING OF SUGAR CANE BAGASSE BY THERMAL PROCESSES. 3. CHEMICAL CHARACTERIZATION OF THE PRODUCTS OBTAINED FROM THE CATALYTIC LIQUEFACTION OF BAGASSE WITH MONOETHANOLAMINE

Abstract The products obtained from liquefaction of sugar cane bagasse with monoethanolamine were characterized using a variety of methods: elemental analysis and UV-visible, FTIR, H1NMR and C13NMR spectrometries. The oils were separated by conventional solubility techniques and were further fractionated into eight fractions (saturated, monoaromatic, diaromatic, triaromatic and poliaromatic hydrocarbons, resins, asphaltenes and pre-asphaltenes). These fractions were characterized by capillary gas cromatograpy with flame ionization detection and gas chromatography/mass spectrometry. Data obtained from simulated distillation of the oils provided useful information regarding product quality.

NOVAS APLICAÇÕES DE SISTEMAS DE PARA EXTRAÇÃO COM FLUIDO SUPERCRÍTICO (SFE)" HOME-MADE".: VI. CONTROLE DE AGROTÓXICOS EM PRODUTOS ALIMENTÍCIOS

In the present work, we describe a SFE home-made system used for pesticide residue extraction in food products. The pesticides were extracted using CO2 in the supercritical state as extracting fluid with and without modifiers. The results obtained by SFE have been better than those obtained by conventional extraction method.

GC-ECD evaluation of dicofol toxicity to tropicalAstyanax bimaculatus schubarti

SummaryEvaluation of the toxicity of Dicofol was carried out onAstyanax bimaculatus schubarti, a characteristic fish species living in tropical rivers and lakes. Experiments were under laboratory controlled conditions with atmospheric air flow and dilution water at 25°C in the static mode. Fish samples were collected and submitted to appropriate analytical procedure: Soxhlet extraction, clean-up by Florisil adsorbent and finally quantification by GC-ECD. The results showed good recoveries (> 89%) for the developed method both in water and fish samples. The lethal concentration, LC50, and the bioconcentration factor, BCF, were 18.13 mg L−1 and 241.70, respectively forAstyanax bimaculatus schubarti demonstrating the lipophilic nature of the studied compound.