Application de l'analyse par activation neutronique a la determination des vins provenant de differents crus. Possibilite d'identification d'un vignoble par la determination des oligo-elements

Neutron activation analysis has been used for the determination of trace elements in different wines coming from various french vineyards. The technics used are non destructive for short and middle half-life radionuclides (²⁸Al−⁷⁶As−⁴⁹Ca−³⁸Cl−⁴²K−²⁷Mg−⁵⁶Mn−²⁴Na−⁵²V). A radiochemical separation is necessary for longer half-life radionuclides (⁶⁰Co−⁵²Cr−¹³⁴Cs−⁵⁹Fe−⁸⁶Rb−⁶⁵Zn). The results of our study show that the identification of vineyards based on the determination of specific oligo-elements can be proposed. However more data are needed to demonstrate that the knowledge of the amounts of specific oligo-elements in a wine corresponding to a given vineyard can be used for disclose frauds more particularly in the cases of wine watering or mixtures of wines coming from different vineyards.      

Concentration de tritium dans l'eau de pluie,l'eau potable et la vapeur d'eau atmospherique au sud de la region parisienne

Tritium levels in precipitation, atmospheric water vapour and tap water were studied in various areas in the South of Paris from 1972 to 1980. Precipitation concentrations were found to exceed the world levels usually observed due to nuclear tests. Significant monthly variations were also observed, which cannot result from the same origin. Tap water levels were constant, the annual concentrations averaged 500 pCi.1⁻¹, which means that the global environmental impact of these local concentrations is negligible. The exposure dose to man is very low (5.10⁻⁴ mGy.y⁻¹) and represents only 1/1000 of the dose from terrestrial radiation.      

Etude des possibilites de dosage du lithium par activation au moyen de protons et de deutons de moyenne energie

The determination of lithium by measuring⁷Be, produced by proton or deuteron activation, has been studied. The extent of interference from boron or beryllium, which also form⁷Be, was measured. The calculated sensitivity limits when activating for one hour with 10μA beams of 14 MeV protons or 25 MeV deuterons are, for lithium, 1·10⁻¹ and 2.5·10⁻² ppm and for boron, 2·10⁻¹ and 1·10⁻¹ ppm, respectively.      

Fabrication de128Xe comme traceur pour l'analyse de traces de xenon

¹²⁸Xe is produced by one-day irradiation of potassium iodide at a neutron flux of 10¹³ n·cm⁻²·s⁻¹ at a rate of 0.9 mm³ TPN for one gram of iodine. Xe is separated from the matrix by melting or hydrolysis. The main part of water is removed from the gas by cooling. Xenon (∼99%) thus obtained is freed from H₂, O₂, N₂, CH₄ and the last traces of water by gas chromatography and used for isotopic analysis.      

Etude de quelques reactions nucleaires induites par les neutrons rapides de pile

Conclusion Dans une première partie, l’étude des réactions engendrées par les neutrons rapides de pile sur douze éléments a montré que certaines de celles-ci pouvaient être utilisées pour un dosage quantitatif. Dans une seconde partie, nous proposons un dosage radiochimique du silicium par la réaction²⁸Si(n, p)²⁸Al qui a, dans nos conditions de travail, sa limite de détermination à 620 μg. A titre de comparaison, signalons que cette limite se situe par irradiation avec des neutrons de 14 MeV, produits au moyen d’un accélérateur (flux de 5·10⁸ n·cm⁻²·sec⁻¹), à environ 10 μg. Le dosage non destructif du silicium dans le diméthylpolysilane est décrit.

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In the first part, the fast-neutron flux available in reactor cores was utilized to define experimentally the sensitivity for the determination of 12 different elements, based on fast-neutron nuclear reactions. The fluxes available with our AGN-201 P reactor are in the range of 10⁹–10¹⁰ n·cm⁻²·sec⁻¹ in the 1–4 MeV region. A good sensitivity was obtained for²⁷Al,⁵²Cr,⁵⁶Fe,²⁸Si,²³Na [by (n, p) reaction],²⁷Al,³¹P,⁸⁹Y [by (n, α) reaction] and¹⁹⁷Au,¹⁸³W,⁸⁹Y [by (n, n′) reaction]; the elements Cl, Ca, Pb failed to give reactions. In the second part, a non-destructive method for the determination of silicium based on the reaction²⁸Si(n, p)²⁸Al is proposed. The limit of determination is about 0.6 mg for a neutron flux of 10⁹ n·cm⁻²·sec⁻¹. As an example, Si in dimethylpolysilane was determined.

     

Gamma background measurements in the Laboratoire Souterrain de Modane

In situ gamma-ray measurements were taken at six locations in the Modane Underground Laboratory. Count rates for gamma radiation within the energy range of 7–2734 keV varied from 15 to 108 γs⁻¹. The arithmetic mean was 79 γs⁻¹ for measurements taken without a collimator. The metamorphic rocks surrounding the Lab are characterized by low activity concentrations of uranium and thorium equal to 12 and 10 Bq kg⁻¹, respectively.     

Concentrations atmospheriques de85Kr dans les hemispheres nord et sud

The evolution of⁸⁵Kr concentrations in the atmosphere has been followed in the Northern hemisphere (France) from June 1966 to February 1979 and in the Southern hemisphere from March 1968 to October 1977 (Tahiti and Terre Adélie). The growth observed during the years 1966–1968 (1.8 pCi·m⁻³ per year) in the Northern hemisphere did not continue in 1969, 1970, 1971, during which period a constant level at 14.8 pCi·m⁻³ per year and even a decrease (12.9 pCi·m⁻³ in 1971) were noticed; this was followed by a new increase of about 0.9 pCi·m⁻³ per year. In the Southern hemisphere, a regular groth from 1968 to 1974 (0.9 pCi·m⁻³ per year) was followed by values stabilized around 14.5 pCi·m⁻³. The curve illustrating the evolution of the Krypton specific activity in the Northern hemisphere from 1954 to February 1979 shows that this increased in a discontinuous way from 1 to 40 disintegrations per minute; nevertheless the present atmospheric activity is very low with a value of only 8·10⁻⁵ MPC.      

Etude des Proprietes de Retention du Filtre Inorganique PbS en vue de ses Applications en Radiochimie Analytique

The fixation behavior of PbS specially prepared for analytical purposes has been studied using batch equilibration technique and chromatographic columns. This inorganic adsorbant shows a high and specific fixation capacity for ions such as Cu²⁺, Hg²⁺, Br⁻ SeO ₄ ²⁻ . An interpretation of the fixation mechanism is proposed.      

Application d'un detecteur a semi-conducteur a l'analyse systematique de l'aluminium

Résumé Après une irradiation neutronique de 7 jours dans un flux de 3·10¹² n·cm⁻²·sec⁻¹, une trentaine d'éléments peuvent être dosés sans séparation chimique dans des échantillons d'aluminium de diverses provenances. Les modalités de mesure et de calcul des radioactivités sont précisées et nous indiquons les limites de détection obtenues. Elles sont comprises entre 5·10⁻² et 5·10⁻⁶ μg/g selon les éléments recherchés. Pour certains d'entre eux (Fe, Zn, Zr) ces limites peuvent être améliorées par une séparation chimique simple.     

Analysis of 19-norandrosterone in human urine by gas chromatography–isotope-dilution mass spectrometry: method adopted by LGC for participation in the Comité Consultatif pour la Quantité de Matière (CCQM) Pilot Study P68

The method used at LGC for analysis of “total” 19-norandrosterone (19-norandrosterone glucuronide plus “free” 19-norandrosterone) in urine for the Comité Consultatif pour la Quantité de Matière Pilot Study (CCQM-P68) is described. The analytical method used was a modified version of the method developed at the National Measurement Institute of Australia, which used a hydrolysis and derivatisation procedure first described by the German Sports University. This method is routinely used by World Anti-Doping Agency-accredited laboratories for sports drug testing. The main modifications made to the method were the use of 19-norandrosterone glucuronide as a calibration standard and 19-norandrosterone glucuronide-d4 as an isotopically labelled internal standard, and the use of a bench-top quadrupole gas chromatograph–mass spectrometer. The results produced by LGC (2.14 ± 0.15 ng g⁻¹ expanded uncertainty, coverage factor k = 2) were in excellent agreement with those from other participating national metrology institutes and thus further validates the exact-matching isotope-dilution mass spectrometric procedures used at LGC for a wide range of reference measurement applications, including measurement of ng g⁻¹ levels of steroids in a biological matrix.     

Dosage non destructif de l’hafnium par activation neutronique et spectrometrie γ de179mHf et de178mHf (periodes respectives: 19.0 et 4.8 s)

A non-destructive method for the determination of hafnium in zirconium and various alloys, based on the formation of^178mHf and^179mHf, is proposed. For a neutron flux of 10⁹ n _th ·cm⁻²·sec⁻¹, the limit of determination is about 0.5 μg. This limit can fall to 50 ng with the multiple irradiation runs system (ten runs at 92-second cycles). The simple determination is complete within 15 minutes, whereas the multiple irradiation runs method requires about 15 minutes longer time.      

Application de l’Analuyse par Radioactivation Neutronique et du Calcul Electronique au Dosage non Destructif de Traces de Chlore dans les Silices-alumines

A method applicable for serial determination of traces of chlorine in SiO₂−Al₂O₃ catalysts by neutron activation is described. The results are evaluated by means of a computer. The³⁸Cl activity is subtracted from the activity of the interfering components (⁵⁶Mn,²⁴Na) and this enables a direct γ-spectrometric determination. In praxis ten samples should be irradiated simultaneously and for this reason 3 standards are irradiated together with the samples to correct for the fluxus gradient. The reproducibility of the method is better than 2 per cent for 10–300 mg samples with a Cl content of 10 ppm.      

Contribution a l’etude du dosage par radioactivation du soufre et du phosphore en tres faibles concentrations dans les metaux de tres haute purete (Aluminium,magnesium, cuivre,fer, nickel)

The analytical procedure for the determination of sulfur in copper by activation with thermal neutrons is given. The purifications necessary to obtain a radiochemically pure precipitate of baryum sulphate are described. The occurrence of some discrepant values in the determinations led to the observation, for the first time, of abnormally high contents of³⁵S^* at a relatively important depth in the samples of irradiated copper (as deep as about 300 μ). Therefore it is necessary to etch the samples to a depth of 300 μ at least on each surface, before doing the chemical separations. Owing to the great influence of the reaction³⁵Cl(n,p)³⁵S^*, the determination of sulfur by thermal neutrons is only possible at contents higher than 10⁻⁶, even if the chlorine concentration is very low (2·10⁻⁸ Cl introduces a correction in terms of sulfur of the order of 10⁻⁶). For sulfur contents lower than 10⁻⁶, the determination is made by irradiation in fast neutrons. The analytical procedure is described and the corrections in the presence of phosphorus and chlorine are discussed. At contents of the order of 10⁻⁸, the corrections are very small and the determination of some 10⁻⁷ of sulfur is easy. Finally, the determination of phosphorus in copper by activation in thermal neutrons is given. The chemical separations are the same as in the preceding case. Contents of the order of 10⁻⁸ phosphorus are determined without difficulty. The results of the determination of sulfur and phosphorus in many samples of copper are indicated: OFHC copper, High Purity copper (99.999%) and different samples of zone refined copper prepared at the Vitry’s Laboratory.      

Amidase and peptidase activities of polyclonal immunoglobulin G present in the sera of patients with rheumatoid arthritis

Polyclonal Immunoglobulin (Ig) G from patients with rheumatoid arthritis (RA) and healthy subjects hydrolyzed carbobenzoxy−Val−Gly−Arg p-nitroanilide and D−Pro−Phe−Arg p-nitroanilide. RA IgG exhibited higher activity against the former substrate, but not the latter. On the other hand, RA IgG showed reduced activity against D−Pro−Phe−Arg methylcoumarinamide, when compared with those of the healthy controls. These results suggest that RA IgGs differ from normal IgGs in the substrate specificity of amidase activity. Preliminary studies have shown that two out of three RA IgG samples cleaved a pentapeptide—Gln−Arg−Arg−Arg−Ala−Ala— which is assumed to be associated with the risk of developing RA (Gregersen, P. K. et al. (1987), Arthritis Rheum. 30, 1205–1213). By contrast, virtually no cleavage of the same peptide was observed with IgG from healthy controls. A peptide analog, Gln−Arg−Arg−Trp−Ala, was not cleaved at all by any IgGs examined either from RA patients or healthy controls.     

Etude de la stabilite de la conformation de copolypeptides alternes

Conformation stability of alternating copolypeptides with the repeating units $\text{Nε-}\text{carbobenzoxy}\text{-}\text{l}\text{-}\text{lysyl}\text{, β-}\text{benzyl}\text{-}\text{l}\text{-}\text{aspartate}\text{(}\text{CLL}\text{-β}\text{BLA}\text{)}\text{and}\text{Nε-}\text{carbobenzoxy}\text{-}\text{l}\text{-}\text{lysyl}\text{, γ-}\text{benzyl}\text{-}\text{l}\text{-}\text{glutamate}\text{(}\text{CLL}\text{-γ}\text{BLG}\text{)}$ has been studied by NMR 220 MHz and by viscosity in deuterochloroform/trifluoroacetic acid (TFA) pair at 25°. NMR spectra show a helix-coil transition at low TFA contents for both copolypeptides as compared to other types of copolypeptides. In the case of poly (CLL-γBLG), the helix begins to collapse at 4% TFA and the transition is complete at 6% TFA. Poly(CLL-βBLA) helix is still more fragile since the transition is complete at 3% TFA. Viscosity measurements seem to indicate helix coil transition to take place at lower TFA content but the disagreement between the two sets of results is only artificial. This low helix stability of both copolypeptides is discussed according to the Lifson—Roig—Cortijo theory taking into account formation of H-bonding between side-chains having different chemical structures. This low helix stability would be due to a co-operative collapsing effect.     

Investigation of H2S oxidation by oxygen on oxide catalysts in sulfur condensation conditions

H₂S oxidation with oxygen has been studied on three industrial oxide catalysts (Fe−Cr−Zn, Cu−Cr−Al, V−Ti−Al). Thermodynamically possible changes in the composition of the catalysts have been evaluated. Regularities determining deep or partial oxidation of H₂S have been found. Deep oxidation is connected to the presence of active oxygen on the catalyst surface; its removal results in a decrease of activity and increase of the sulfur selectivity. Oscillations caused by periodic adsorption-desorption of sulfur on the catalyst surface have been observed on the most active V−Ti−Al catalysts in oxygen excess.     

L'influence de la temperature sur l'echange anionique

The influence of temperature on the distribution coefficients of Zn ions in systems ethanol or acetone, hydrochloric acid and Dowex 1×8 ion exchange resin (100–200 mesh) was studied. TheK _d-values increase a little with the temperature. The thermodynamic constants for some systems were calculated.      

Etude theorique de la premiere protonation de la proflavine

A comparison between theory and experiment (the last performed by J. H. Lhoste) gives consitent results pertaining to the difference in acid-base behaviour of proflavin in the ground state and in the excited singlet and triplet states. In particular, several facts emerge. An extraordinary inequality between the different pK′s of acid-base equilibria are indicated: p_triplet^K < p_fondamental^K < p_singulet^K A change occured by protonation in the electronic configuration of the lowest triplet state of that molecule and the variation of solvation energy during the absorption ground state-first excited singlet state plays an important part.     

Water Activity and Osmotic Coefficients in Solutions of Glycine,Glutamic Acid,Histidine and their Salts at 298.15 K and 310.15 K

From vapor pressure osmometry data, the activity of water, osmotic coefficients and mean ionic activity coefficients of glycine (m=0.006−3.2 mol⋅kg⁻¹), L-histidine (m=0.005−0.23 mol⋅kg⁻¹), L-histidine monohydrochloride (m=0.008−0.63 mol⋅kg⁻¹), glutamic acid (m=0.004−0.05 mol⋅kg⁻¹), sodium L-glutamate (m=0.007−0.6 mol⋅kg⁻¹), and calcium L-glutamate (m=0.008−0.6 mol⋅kg⁻¹) have been obtained in aqueous solutions at 298.15 and 310.15 K. The Pitzer equations and the mean spherical approximation (MSA) are used for theoretical modeling. The results are supplied as reference thermodynamic material for the characterization of more complex molecules such as proteins.     

Solubility of neptunium oxide in the KURT (KAERI Underground Research Tunnel) groundwater

The solubilities of NpO₂(s) in the KURT (KAERI Underground Research Tunnel) granitic groundwater with low ionic strength were measured experimentally and calculated by a geochemical code. Then these results were compared with each other as well as with foreign results. The concentrations of neptunium were measured as 6·10⁻⁸−2·10⁻⁸ mol/L at a pH = 9.5–11.1 and Eh = −0.2 V, and less than 5·10⁻⁹ mol/L at a pH = 11.8–13.0 and Eh = −0.3–0.44 V. The dominant aqueous species were presumed as Np(OH)_x(CO₃)_y ^4−x−2y complexes and Np(OH)₄(aq) at pH = 9.5–13 under the Eh<−0.2 V reducing condition.