PDMS extraction bars for the determination of volatile aromatic hydrocarbons in water and wastewater.

In this study, the preparation and application of extraction bars of PDMS were investigated to preconcentrate and determine benzene, toluene, ethylbenzene, and xylene in water and wastewater by means of HPLC with fluorescence detection. Aliquot samples from hospital wastewater were used as the model effluent. The independent variables for the sorptive extraction were as follows: ionic strength (added amounts of NaCl); pH; temperature and time of absorption; temperature and time of desorption. Under optimized conditions, by using a factorial design, the suspended extraction bars could allow the determination of benzene, toluene, ethylbenzene, and xylene (1.20 ± 0.05 µg/L; 10.40 ± 0.02 µg/L; 1.80 ± 0.04 µg/L; 15.9 ± 0.04 µg/L, respectively) in hospital effluent (fortified samples), by recoveries of 71.9 ± 4.9 to 74.8 ± 5.6%. This procedure represents an innovation that eliminates the time-consuming stage of vacuum microfiltration, and allows the determination of volatile organic compounds by HPLC. As far as we know, this procedure is original and represents an important contribution to the field.

Determination of anti-anxiety and anti-epileptic drugs in hospital effluent and a preliminary risk assessment.

In this study, an analytical methodology was developed for the determination of psycho-active drugs in the treated effluent of the University Hospital at the Federal University of Santa Maria, RS - Brazil. Samples were collected from point A (Emergency) and point B (General effluent). The adopted methodology included a pre-concentration procedure involving the use of solid phase extraction and determination by liquid chromatography coupled to mass spectrometry. The limit of detection for bromazepam and lorazepam was 4.9 ± 1.0 ng L(-1) and, for carbamazepine, clonazepam and diazepam was 6.1 ± 1.5 ng L(-1). The limit of quantification was 30.0 ± 1.1 ng L(-1), for bromazepam, clonazepam and lorazepam; for carbamazepine was 50.0 ± 1.8 ng L(-1) and was 40.0 ± 1.0 ng L(-1) for diazepam. The mean concentrations in the Emergency and General effluent treated currents were as follows: for bromazepam, 195 ± 6 ng L(-1) and 137 ± 7 ng L(-1); for carbamazepine, 590 ± 6 ng L(-1) and 461 ± 10 ng L(-1); for diazepam, 645 ± 1 ng L(-1) and 571 ± 10 ng L(-1); for lorazepam, 96 ± 7 ng L(-1) and 42 ± 4 ng L(-1); and for clonazepam, 134 ± 10 ng L(-1) and 57 ± 10 ng L(-1). A preliminary risk assessment was conducted: carbamazepine and diazepam require considerable attention owing to their environmental toxicity. The occurrence of these psychoactive-drugs and the environmental risks that they pose demonstrated the need for a more efficient treatment system. As far we are aware, there have been no comparable studies to this on the hazards of hospital effluents in Brazil, and very few that have carried out a risk assessment of psycho-active drugs in hospital effluent in general.