122,027 research outputs found
Report to Ministry of Health
No full textEmerging pollutants are thought to be responsible for the most significant share of environmental, human health and economic risk. Although the universe of chemical pollutants is enormous, we only monitor and have studied a minor fraction.
The study of the fate of the emerging pollutants and their transformation products in wastewater-treatment plants (WWTP) is of paramount importance, since it can provide valuable information on the human consumption of various drugs. Sewage epidiomiology is the new field that was develloped for the estimation of illicit drug use based on measurements of urinary excreted illicit drugs and their metabolites in untreated wastewater. Within this approach, human metabolic excretion products resulting from drug consumption are rapidly collected and pooled by the sewage systems, providing valuable evidence of the amount and type of drug consumed by a population.
The main objective of this research is the contribution to the current knowledge on the actual burden of micropollutants on the environment and on the effect they have on the human health
Targeted determination of new psychoactive substances, drugs of abuse, psychoactive pharmaceuticals and other biomarkers in wastewater by LC-Q-ToF-HRMS
No full textData for: Fundamental pricing laws and long memory effects in the day-ahead power market
No full textSee enclosed fil
Ozonation of ranitidine: effect of experimental parameters and identification of intermediates
No full textThe aim of this study was to reveal the effects of various operational parameters on the ozonation kinetics of the histamine-2 blocker drug ranitidine (RAN) in aqueous solutions and to detect and identify possible transformation products (TPs) of RAN produced during the ozonation experiments.
The influence of the solution’s pH value, the initial concentrations of the oxidant and analyte, the matrix effect and the organic matter presence on RAN’s removal were evaluated. Results indicated high reactivity of RAN with molecular aqueous ozone. Initial
ozone concentration and pH were proven major process parameters. Alkaline pH values and increased ozone initial concentrations promoted degradation kinetics and overall mineralization. Although RAN mineralization at neutral and acidic pH was restricted
(maximum 22%), it increased at pH 10. Dissolved Organic Matter (DOM) acts as an antagonistic agent to RAN degradation, limiting its % removal. The effect of inorganic ions in the matrix did not seem to affect RAN ozonation. Eleven (11) TPs were identified and structurally elucidated, using Reversed Phase (RP) and
HILIC LC-Q-ToF-MS. Most of the TPs (P-304, P-315b, P-299b, P-333, P-283) are generated by the attack of ozone at the double bond or the adjacent secondary amine, with the abstraction of NO2 moiety, forming TPs with an aldehyde group and an imine C=N bond. Oxidized derivatives with a carboxylic group (P-315a, P-331a, P-331b, P-299a) are also formed. Ranitidine S-oxide was identified as an ozonation product (P-330) and its structure was confirmed through the analysis of a reference standard. P-214, was also produced during ozonation, through the C-N bond rupture adjacent to the NO2 moiety. HILIC was successfully used complementary to RP, either for the successful separation and identification of isomeric TPs or for the elution of new TPs that were not eluted in the RP
chromatographic system. Retention time (tR) prediction was also used as a complementary tool for the identification of TPs. The obtained results supported the proposed structures, since the predicted tR of most compounds in both RP and HILIC were in accordance with the experimental ones
Ozonation of ranitidine under various physicochemical conditions. Degradation kinetics and intermediate by-products
No full textPEAKTRAMS: An automated computational approach for the simultaneous detection of features in reverse phase and hilic hrms screening
No full textComparison of chromatograms obtained in reserved phase (RP) liquid chromatography and hydrophilic interaction liquid chromatography (HILIC) can provide valuable information for the identification and confirmation of suspect and non-target compounds. The plausibility of the obtained chromatographic retention times (RTs) in both modes as well as the ψomparison of the MS/MS spectra are strong points to be considered. This work presents the development of a novel automatic approach for the identification of common peaks between RP and HILIC chromatograms. The core of the program is written in R-project while a simple and user friendly graphical user interface (GUI) was built in JAVA.
The first step consists of the introduction of the target chromatograms of the same sample (one obtained by RP and one by HILIC) plus the corresponding blank chromatograms. Blank
subtraction was performed first using an algorithm to find in each scan the common m/z features (with a given mass accuracy). This algorithm also considers the RTs (a tolerance interval is applied), so the subtraction takes place even with slight drifts in the RTs between target and blank chromatograms. After blank subtraction, two different lists are obtained with the detected peaks in both RP and HILIC modes. Subsequently, m/z values are compared and matches are listed.
The developed workflow was validated with solvent standards and with spiked wastewater samples with a mixture of compounds with a wide range of physicochemical properties.
Successful results were obtained for 26 out of the 27 evaluated substances, allowing the recording of the corresponding RTs in both RP and HILIC mode
Fate of selected emerging pollutants and formation of transformation products in activated sludge batch reactors under aerobic/anoxic/anaerobic conditions
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