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This study evaluates the feasibility of commercial chitosan (CQ) and modified chitosan (MQ) by epichlorohydrin to be used as a solid phase to remove fluorescein (FSC) from aqueous solutions by two different approaches: in batch and on a fixed column bed. For the batch study, all parameters that influence sorption capacity were evaluated, such as: pH, mass, ionic strength, temperature and time of contact. In the optimized condition, 75% removal was obtained for FSC using CQ, while the modification allowed an increase up to 99%, as well as an increase in the stability of the polymer. In the fixed column bed study, the influence of all the parameters was evaluated through breakthrough curves, and the thermodynamics parameters of each approach were obtained. The results of these studies demonstrate that the modification with epichlorohydrin enhanced the sorptive properties (from 35% to 95% in fixed bed experiments) and the polymer stability (making it insoluble), making it suitable to be used in wastewater treatment. [ABSTRACT FROM AUTHOR]

This paper shows the result of a study on the extent of cocaine contamination in Real banknotes in circulation in the state of Rio de Janeiro (Brazil). A study of the percentage of contaminated banknotes was made, as well as a study on the contamination of banknotes based on different values, and a study of contamination depending on the region where the banknote was collected. The idea of this last study was to verify if the peculiar characteristics of the region of study (in particular, the city of Rio de Janeiro) influence the amount of cocaine in the banknotes. Some regions have higher consumption/drug trafficking of cocaine than others. Also, some contaminated banknotes confiscated directly from drug dealers and users were analyzed. Also, is showed in this paper all the optimization of the available analytical techniques for making the measurements possible. [ABSTRACT FROM AUTHOR]

A flow injection Fourier transform infrared spectrometric procedure has been developed for the determination the dithiocarbamate pesticides Ziram and Thiram in solid samples. All the operations involved, such as extraction, filtration and measurement, were integrated in the experimental set-up in order to avoid excessive manipulation of samples and standards. Ultrasonic assisted and mechanical extraction were evaluated for the solubilization of the analytes and, additionally, the effect of carrier flow rate, sample loop volume and the ratio between sample mass and volume of solvent employed were studied. Quantitative extractions with chloroform were obtained for both Ziram and Thiram, after 5 and 2 min, respectively, of mechanical shaking of sample slurries. Absorbance measurement, in the wavenumber range of 1600-1460 cm-1 for Ziram and 1400-1315 cm-1 for Thiram, was carried out, and the area values of the peaks obtained, as a function of time, were interpolated in external calibration lines prepared from standard solutions of Ziram and Thiram in chloroform. Analyses of commercial formulations and spiked soil samples incubated two weeks were in a good agreement with values found by other methodologies. Absolute detection limits of 400 micrograms for Ziram and 785 micrograms for Thiram and variation coefficients of 6.4% and 2.5% were obtained by use of the aforementioned methodology.