Development And Validation Of A Method For Determining Estrogenic Compounds In Surface Water At The Ultra-Trace Level Required By The EU Water Framework Directive Watch List.

Natural estrogens (estrone: E1, 17ß-estradiol: E2, estriol: E3) and the synthetic estrogen (17α-ethinylestradiol: EE2) are endocrine disruptors harmful to aquatic wildlife. The European Commission included these molecules in the surface water Watch Lists issued in 2015 and 2018 under the Water Framework Directive regarding emerging aquatic pollutants, proposing maximum detection limits (LOD) of 0.035 ng/L for EE2 and 0.4 ng/L for E1 and E2. Attaining these limits represents a challenge even with the most up-to-date analytical tools, in particular in surface water. A two-step sample preparation, involving a preliminary extraction of a whole water sample on a solid-phase extraction (SPE) disk and further purification on a Florisil SPE cartridge, was optimized. The purified extract was derivatized subsequently and quantified by LC-MS/MS. The main goal was to maximize the recoveries to achieve the very low LODs required by the European Watch Lists. The method was fully validated in seven surface water. The LODs calculated were below the maximum acceptable limits required by the European Commission.

Redox tuning and species distribution in Maya Blue-type materials: a reassessment.

Maya Blue-type specimens prepared from indigo (1 wt %) plus kaolinite, montmorillonite, palygorskite, sepiolite, and silicalite are studied. Liquid chromatography with diode array detection, ultra-performance liquid chromatography coupled with mass spectrometry, and pyrolysis-silylation gas chromatography-mass spectrometry analyses of the extracts from these specimens combined with spectral and solid-state voltammetry, electrochemical impedance spectroscopy, and scanning electrochemical microscopy techniques provide evidence for the presence of a significant amount of dehydroindigo and isatin accompanying indigo and other minority organic compounds in all samples. Solid-state electrochemistry data permits the estimatation of indigo loading in archeological Maya Blue, which is in the range of 0.2 to 1.5 wt %. These results support a view of 'genuine' Maya Blue-type materials as complex polyfunctional organic-inorganic hybrids.

Determination of fragrance allergens in indoor air by active sampling followed by ultrasound-assisted solvent extraction and gas chromatography-mass spectrometry.

Fragrances are ubiquitous pollutants in the environment, present in the most of household products, air fresheners, insecticides and cosmetics. Commercial perfumes may contain hundreds of individual fragrance chemicals. In addition to the widespread use and exposure to fragranced products, many of the raw fragrance materials have limited available health and safety data. Because of their nature as artificial fragrances, inhalation should be considered as an important exposure pathway, especially in indoor environments. In this work, a very simple, fast, and sensitive methodology for the analysis of 24 fragrance allergens in indoor air is presented. Considered compounds include those regulated by the EU Directive, excluding limonene; methyl eugenol was also included due to its toxicity. The proposed methodology is based on the use of a very low amount of adsorbent to retain the target compounds, and the rapid ultrasound-assisted solvent extraction (UAE) using a very low volume of solvent which avoids further extract concentration. Quantification was performed by gas chromatography coupled to mass spectrometry (GC-MS). The influence of main factors involved in the UAE step (type of adsorbent and solvent, solvent volume and extraction time) was studied using an experimental design approach to account for possible factor interactions. Using the optimized procedure, 0.2 m(-3) air are sampled, analytes are retained on 25 mg Florisil, from which they are extracted by UAE (5 min) with 2 mL ethyl acetate. Linearity was demonstrated in a wide concentration range. Efficiency of the total sampling-extraction process was studied at several concentration levels (1, 5 and 125 microg m(-3)), obtaining quantitative recoveries, and good precision (RSD<10%). Method detection limits were < or =0.6 microg m(-3). Finally, the proposed method was applied to real samples collected in indoor environments in which several of the target compounds were determined.