EFSA is conducting pan‐European dietary exposure and risk assessments related to actual levels of pesticide residues in food commodities. These assessments use the pesticide occurrence data generated under the official monitoring programs of Member States, the consumption data from EFSA's comprehensive food consumption database and pesticide‐specific information such as processing factors. Currently no harmonised list of processing factors is available within Europe and worldwide. The overall objective of this project is to develop a database of validated processing factors, which is compatible with the EFSA food classification and description system FoodEx 2.
In the first part of the project, a compendium of representative processing techniques was elaborated which serves as a standard description of all relevant processes and as a basis for validation of processing studies. In the second part of the project all relevant processes and raw and processed commodities were coded according to FoodEx2. In the third and last part of the project all processing studies used by EFSA in their Conclusions and Reasoned Opinions issued until 30/06/2016 were re‐evaluated according to uniform quality criteria and reported in a database. The database is provided as a flat Excel spreadsheet. Information on processing conditions, on analytical methods, storage stability and GLP was collected from the studies and was used to judge the acceptability of each processing study. The representativeness of the processing conditions applied in the studies was judged by comparing them to the compendium of representative processing techniques. Processing factors (PF) were derived from the studies according to comprehensible calculation rules and based on the residue definitions for monitoring. The individual PF were judged for their acceptability. For each commodity/process/active substance combination a median PF was calculated from the individual ones, based on the trials from one or more studies. The database is a ready‐to‐use inventory of PF for pesticides in a variety of processed food items.
In a pilot project a second database was set up with processing factors based on the residue definition for dietary risk assessment. Extension of this database is recommended.
The phases of HMX and their transitions were investigated by thermal analysis using X‐ray diffraction. Series of diffraction pattern were measured, while the samples were heated and cooled. The thermal expansion coefficients and the colume changes at the transitions were extracted from the diffraction series. A contraction of β‐HMX was found before changing into δ‐HMX resulting in a high volume difference during the transition. On cooling, the reconversion of the high temperature phase requires days. It is further slowed down by decomposition products, which are formed at temperatures beyond 490 K. The final reconversion results in mixtures of α‐and βHMX.
The mechanical sensitivities and the buring rates of the HMX phase were determined. The high sensitivity of δ‐HMX against impact together with its slow reconversion creates handling risks when the HMX is exposed to temperatures above 440 K.
Die Menge der an der Oberfläche gebundenen OH‐Gruppen wurde bei einem feinteiligen Anatas durch Deuterium‐Austausch, Acetylierung und Reaktion mit SOCl2 bestimmt. Nach Entgasen bei 150° wurden etwa 4,9 OH‐Gruppen/100 Å2 gefunden, gegenäber einer fär eine vollständig hydroxylierte Oberfläche abgeschätzten Menge von 12–14 OH/100 Å2. Der thermische Abbau der OH‐Gruppenbelegung begann unterhalb 200° und war bei 350° vollständig. Bei der Einwirkung von H2O‐Dampf wurde nur die Hälfte der urspränglich vorhandenen OH‐Gruppen zuräckgebildet, unter flässigem H2O wurde die Oberfläche vollständing rehydroxyliert. Das unterhalb 150° chemisorbierte H2O därfte molekular, nicht in Form von OH‐Gruppen vorliegen.
Feinteiliger Anatas wurde mit NaF‐Lösungen umgesetzt. Dabei werden OH‐Gruppen der TiO2‐Oberfläche durch F− ersetzt. In ungepufferter Lösung oder bei pH‐Werten am oder wenig über dem isoelektrischen Punkt (pH 6,6) wird nur die Hälfte der vorhandenen OH‐Gruppen. Zugleich tauschen die übrigen, sauren OH‐Gruppen H+ ‐Ionen gegen Na+ aus. In stärker saurem Milieu (pH 4,6) werden auch die sauren OH‐Gruppen durch Fluor ersetzt.
The phase behavior of 1,1‐Diamino‐2,2‐dinitroethylene (FOX‐7) was investigated by means of temperature resolved X‐ray powder diffraction. Three phases were observed, and α‐ and β‐FOX‐7 were identified by X‐ray diffraction. The following transition scheme was found:
Heating: α → β → γ at 113 °C (α→β) and 173 °C (β→γ)
Cooling: α (+γ) ← γ between 50 and 75 °C
The α/β‐transition is completely reversible, and the γ/α‐transition on cooling revealed to be incomplete. A fourth phase which is described in literature was not found.
Die Adsorption verschiedener Säuren an einem feinteiligen Anatas wurde untersucht. Vor allem Phosphorsäure, Arsensäure, Schwefelsäure und Essigsäure werden spezifisch adsorbiert. Salzsäure und Perchlorsäure werden nicht adsorbiert. Phosphat‐Ionen werden auch aus NaH2PO4‐ und Na2HPO4 ‐Lösung gebunden; zugleich werden Natriumionen adsorbiert. Bei diesen Reaktionen werden OH− ‐Ionen der TiO2‐Oberfläche durch Anionen, z. B. H2PO 4−‐Ionen, ersetzt. Die Bindung der adsorbierten H2PO 4−‐Ionen ist nicht rein ionisch. Adsorbierte Essigsäure liegt als Acetat vor, wir das Infrarotspektrum zeigt. NO2 reagiert mit den basischen OH−‐Ionen der Oberfläche unter Disproportionierung; dabei werden die OH−‐Ionen durch NO 3− ersetzt.
Bei fünf untersuchten TiO2 ‐Präparaten entspricht die Phosphorsäure‐ Adsorption jeweils der Hälfte des gesamten Gehaltes an OH‐Gruppen. Nur ein Teil deer Oberfläche ist mit OH‐Gruppen belegt. Die maximale Belegungsdichte beträgt etwa 7,5 μMol OH/m2.
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