Analysis of Food by High Performance Liquid Chromatography Coupled with Coulometric Detection and Related Techniques: A Review

The development of single coulometric cells in combination with high performance liquid chromatography to dual cells and to the coulometric electrode array detector is described. An overview is given about the application of these methods in food chemistry. Easily oxidizable compounds, such as phenolic substances, pesticides, or vitamins, can be determined, as well as substances with high oxidation potentials or electroinactive compounds. Substances exhibiting poor electrochemical activity can be transformed to electroactive compounds by precolumn derivatization, postcolumn photochemical reactions, postcolumn enzyme reactors, or by using the oxidative/reductive mode for coulometric electrode array detection. Furthermore, it is shown that the interesting combination of high performance liquid chromatography with electrochemistry and mass spectrometry has opened further possibilities with respect to interpretation of redox reactions, drug metabolism studies, metabolomics, and electrochemical derivatization.

17α-Ethinylestradiol and 17β-estradiol removal from a secondary urban wastewater using an RBC treatment system

The presence of micropollutants that include endocrine-disrupting compounds (EDC) in aquatic environments is currently one of the most relevant aspects of water quality due to their adverse effects on aquatic organisms and human health. From the several categories of EDC, 17β-estradiol (E2) is a natural hormone, which is prevalent in vertebrates, associated with the female reproductive system and maintenance of the sexual characters. 17α-Ethinylestradiol (EE2) is a synthetic hormone produced from the natural hormone E2 and is an essential component of oral contraceptives. These compounds are susceptible to bioconcentration and have high potential to bioaccumulation. Wastewater treatment plants are the main point source of E2 and EE2 into aquatic environments, but conventional wastewater treatment systems are not specifically designed for steroid removal. To overcome this problem, biological tertiary treatment may be a solution for the removal of emergent pollutants such as E2 and EE2. The main purpose of the present study is to provide a solution based on the optimization of a rotating biological contactor system to remove estrogens, specifically E2 and EE2, and to quantify their removal efficiency on different matrices, namely real wastewater and different synthetic wastewaters. All assays presented viable removal efficiencies for compound E2 with values always above 50%; real wastewater yielded the highest removal efficiencies. EE2 removal had better removal efficiencies with synthetic wastewater as feed solution, with removals above 15%, whereas the removal efficiency with real wastewater was inexistent.

Priority pesticides in sediments of European coastal lagoons: A review

This review summarizes the legislation applied to pesticides and highlights the physicochemical properties of the past and recently listed PPs under Water Framework Directive (WFD). It reports important information regarding the analysis, occurrence and long-term screening of PPs in sediments of European coastal lagoons. Among the entire list of PPs, those analyzed have been the organochloride insecticides, such as lindane, hexachlorobenzene and DDT. Although flood events pointed to the possible redistribution of pesticides, which may increase under climate change conditions, few studies are available concerning PPs screening in sediments of European coastal lagoons. Data is scarce not only in terms of the number of listed PPs that have been analyzed but also in terms of their long-term screening. This lack of data on PP concentrations is probably a consequence of the fact that less importance is given to the sediments contamination/quality.

Pathways of priority pesticides in sediments of coastal lagoons: The case study of Óbidos Lagoon, Portugal

This study reports the concentrations of the priority pesticides (PPs) in 14 surface sediments and 21 layers of a sediment core from Óbidos Lagoon, a shallow Portuguese coastal lagoon. Results show that the PPs are confined to the upper part of the lagoon that receives most of the inputs from surface runoff of the surrounding agricultural fields and from small tributaries. Past and recent applied PPs were registered in sediments, aluminum normalized concentrations varying between 0.05×10(-7) and 6.85×10(-7). The PP risk assessment based on sediment quality guidelines like the "Probable Effect Level" (PEL) shows no biological effects in either sediments or aquatic organisms of Óbidos Lagoon, except for dieldrin, lindane, DDT, heptachlor epoxide and its parent compound heptachlor.

Screening of priority pesticides in Ulva sp. seaweeds by selective pressurized solvent extraction before gas chromatography with electron capture detector analysis

This work reports a fast and reliable analytical method for the screening of priority pesticides (PPs) in Ulva sp. seaweeds by gas chromatography with electron capture detection. Extraction and sample clean-up were performed in one single step by selective pressurized liquid extraction (SPLE). Several parameters affecting SPLE performance were optimized. Method performance was compared with standard Soxhlet extraction. Significant decrease of the time of analysis with better recoveries for a greater number of PPs was achieved by SPLE. Average recoveries ranged from 71 to 103% with RSD < 10%. Field application showed the presence of PP in the range of 3-11 ng g(-1) in seaweeds collected in a coastal lagoon after a long period of heavy rains. These results suggest that Ulva sp. seaweeds tend to accumulate PPs and have the potential to be used as early alert signals of aquatic pollution especially after rains and storm events.

Development of a biodegradable bioadhesive containing urethane groups

Surgical adhesives consist on an attractive alternative to suturing or stapling since they can accomplish other tasks, such as haemostasis and the ability to seal air leakages. The application of adhesives would also reduce the surgeries procedure time since they represent an easier and faster method to establish tissue adhesion. The aim of this work was the development of a biodegradable urethane pre-polymer that presents the capacity of reacting with the amino groups present in the biological molecules. Urethanes based on polycaprolactone diol (PCL) were synthesized by reaction of the molecule either with isophorone diisocyanate (IPD-isocyanate) or hexamethylene diisocyanate (HDI-isocyanate). The characterization of the materials was accomplished by: ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared), determination of swelling capacity, stability of NCO groups in the presence of humidity conditions, reaction with aminated substrates (as a simulation of the living tissues) and determination of surface energy by contact angle measurement. The haemocompatibility of the PU was also evaluated by thrombosis and haemolysis tests.

[Mass culture and female representations in São Paulo in the 1920's]

Era muito claro que as mulheres estavam reelaborando seus papéis dentro da sociedade moderna. As revistas de fãs, o cinema e a publicidade apresentavam repetidamente artigos e imagens sobre jovens mulheres e as identificavam com a juventude e a modernidade em si. Este artigo analisa como a cultura de massas, especialmente o cinema, apelava para a construção dessa imagem feminina como corolário da modernidade pois ela se opunha frontalmente às mulheres do lar provinciano, arcaico, e representava antes de tudo a mulher moderna, que trabalha fora e que participa ativamente da vida pública.