Autoxidation of lipids in parchment

Historic parchment is a macromolecular material, which is complex due to its natural origin, inhomogeneity of the skin structure, unknown environmental history and potential localised degradation. Most research into its stability has so far focussed on thermal and structural methods of analyses. Using gas chromatographic analysis of the atmosphere surrounding parchment during oxidation, we provide the experimental evidence on the production of volatile aldehydes, which can be the products of lipid autoxidation. Oxidation of parchment with different aldehyde emissions was additionally followed in situ using chemiluminometry and the same techniques were used to evaluate the oxidation of differently delipidised parchment. It was shown that the production of peroxides and the emission of aldehydes from the material decrease with lower lipid content. Building on this evidence, we can conclude that the presence of lipids (either initially present in the skin or resulting from conservation intervention) leads to oxidative degradation of collagen and that the non-destructive analysis of the emission of volatiles could be used as a quick tool for evaluation of parchment stability

Speciation of trace amounts of aluminium in environmental samples by cation-exchange FPLC - ETAAS

Cation-exchange fast protein liquid chromatography - electrothermal atomic absorption spectrometry (FPLC - ETAAS) was applied for the speciation of trace amounts of aluminium. An aqueous 8 mol dm$^{-3}$ NH$_4$NO$_3$ linear gradient elution in 10 minutes enabled separation of positively charged monomeric aluminium species in aqueous solution. Separated aluminium species were collected in 0.5 cm$^3$ fractions and aluminium determined “off line" after fourfold dilution by ETAAS. The ability of NH4NO3 to completely decompose at low temperature in the graphite tube during the ashing step enabled quantitative and reproducible determination of aluminium. After applying Chelex-100 resin in a cleaning procedure of the eluent, the eluent blank was very low ($< 1.0$ ng cm$^{-3}$ Al). When 1 cm$^3$ of sample was injected on the column resin, the limit of detection (3 s) for the separated aluminium species determined by ETAAS was found to be 3 ng cm$^{-3}$. Good repeatability of measurement of separated aluminium species (relative standard deviation $\pm 5\%$) was obtained under the recommended analytical conditions. The influence of some inorganic and organic complexing ligands at pH values of 4.0 and 6.0 on the speciation of aluminium was also investigated. The method developed was successfully applied for the speciation of aluminium in soil extracts and natural water samples at ng cm$^{-3}$ levels

Determination of Cobalt in Biological Materials by RNAA Via Induced Short-lived 60mCo

A procedure for determination of cobalt in biological materials using the short-lived induced radionuclide 60mCo is described. 60mCo has been rarely used as an indicator radionuclide in NAA due to low concentrations usually found in biological materials and due to its short-half life (t1/2 = 10.5 min). Using the described procedure, based on dissolution of the irradiated sample, precipitation of Co with C5H10NNaS2*3H2O, extraction of the complexes formed into toluene, purification and counting by gamma spectrometry, Co was determined in biological materials at ng g-1 levels.JRC.D.4-Isotope measurement

Isotope Ratio Measurements of pg-size Plutonium Samples using TIMS in Combination with "Multiple Ion Counting" and Filament Carburization

A new sample preparation procedure for isotopic measurements using Thermal Ionization MAss Spectrometry (TIMS) was developed which employs the technique of carburization of rhenium filaments. Carburized filaments were prepared in a special vacuum chamber in which the filaments were exposed to benzene vapour as a carbon supply and carburized electrothermally. To find the optimal conditions for the carburization and isotopic measurements using TIMS, the influence of various parameters such as benzene pressure, carburization current and the exposure time were tested. As a result, carburization of the filaments improved the ionization efficiency by one order of magnitude. Additionally, a new "multi-dynamic" measurement technique was developed for Pu isotope ratio measurements using a "multiple ion counting" (MIC) system. This technique was combined with filament carburization and applied to the NBL-137 isotopic standard and samples of the NUSIMEP 5 inter-laboratory comparison campaign, which included certified plutonium materials at the ppt-level. The multi-dynamic measurement technique for plutonium, in combination with filament carburization, has been shown to significantly improve the precision and accuracy for isotopic analysis of environmental samples with low-levels of plutonium.JRC.D.4-Isotope measurement

Purification of recombinant adenovirus type 3 dodecahedric virus-like particles for biomedical applications using short monolithic columns.

Adenovirus type 3 dodecahedric virus-like particles (Ad3 VLP) are an interesting delivery vector. They penetrate animal cells in culture very efficiently and up to 300,000 Ad3 VLP can be observed in one cell. The purification of such particles usually consists of several steps. In these work we describe the method development and optimization for the purification of Ad3 VLP using the Convective Interaction Media analytical columns (CIMac). Results obtained with the CIMac were compared to the already established two-step purification protocol for Ad3 VLP based on sucrose density gradient ultracentifugation and the Q-Sepharose ion-exchange column. Pure, concentrated and bioactive VLP were obtained and characterized by several analytical methods. The recovery of the Ad3 VLP was more than 50% and the purified fraction was almost completely depleted of DNA; less than 1% of DNA was present. The purification protocol was shortened from five days to one day and remarkably high penetration efficacy of the CIMac-purified vector was retained. Additionally, CIMac QA analytical column has proven to be applicable for the final and in-process control of various Ad3 VLP sample