Analytical evaluation of the protection offered by sealed tractor cabins during crop pulverization with fenitrothion.

The practice of large-scale agriculture requires the use of pesticides in order to maximize production. This activity has gained increasing attention in recent years, especially from rural workers, due to the risks associated with long-term exposure to pesticides. To minimize these risks, personal protection equipment (e.g., covers, gloves, and goggles) and collective protection equipment (e.g., agricultural tractors with sealed cabins) have been developed. In general, these approaches are intended to reduce the contact of farmers and agricultural machinery operators with the more toxic and stable compounds, an example of which is fenitrothion. In this study, fenitrothion was used as a marker to evaluate the protection afforded inside a sealed tractor cabin. To simulate the pesticide exposure, tests were performed using artificial cotton targets as passive adsorptive agents inside the cabin during the pesticide application. Samples were extracted according to the US Environmental Protection Agency (USEPA) procedure using ultrasonic extraction and as proposed by the Brazilian Standard for Solid Waste Classification (NBR 10004). The extracts were analyzed by high-performance liquid chromatography with diode array detection (HPLC-DAD). The chromatographic method was optimized using a factorial design. The combined results indicated that the best conditions were achieved using a mobile phase with a water/acetonitrile ratio of 35:65, a column temperature of 40 °C, and a flow rate of 1.0 mL/min, with a total analysis time of <10 min. The method was evaluated in the linear range of 0.50 to 2.01 mg/kg, with a determination coefficient of 0.9886. The precision was evaluated on different days and the relative standard deviations were between 0.17 and 3.41 %. In relation to the accuracy, recovery values of 95 to 104 % were obtained. The detection and quantification limits were 0.18 and 0.50 mg/kg, respectively. None of the target cottons showed concentrations of fenitrothion above the limit of detection of 0.18 mg/kg.

Development of a fast capillary electrophoresis method for the determination of propranolol-Total analysis time reduction strategies.

The aim of this study was to develop a fast capillary electrophoresis method for the determination of propranolol in pharmaceutical preparations. In the method development the pH and constituents of the background electrolyte were selected using the effective mobility versus pH curves. Benzylamine was used as the internal standard. The background electrolyte was composed of 60mmolL(-1) tris(hydroxymethyl)aminomethane and 30mmolL(-1) 2-hydroxyisobutyric acid, at pH 8.1. Separation was conducted in a fused-silica capillary (32cm total length and 8.5cm effective length, 50microm I.D.) with a short-end injection configuration and direct UV detection at 214nm. The run time was only 14s. Three different strategies were studied in order to develop a fast CE method with low total analysis time for propranolol analysis: low flush time (Lflush) 35runs/h, without flush (Wflush) 52runs/h, and Invert (switched polarity) 45runs/h. Since the three strategies developed are statistically equivalent, Wflush was selected due to the higher analytical frequency in comparison with the other methods. A few figures of merit of the proposed method include: good linearity (R(2)>0.9999); limit of detection of 0.5mgL(-1); inter-day precision better than 1.03% (n=9) and recovery in the range of 95.1-104.5%.