Catalogue des objets d'art et d'ameublement du XVIIIe siècle, orfèvrerie ancienne et moderne, bijoux, faïences et porcelaines, objets de vitrine..., tableaux anciens et modernes, gravures..., le tout dépendant de la succession de madame la vicomtesse de Rainneville... vente... 1-4 mars 1909... / [experts] Léon Helft, Féral, Falize

[Vente. Art. 1909-03-01 - 1909-03-04. Paris]

Alternativas quimiométricas para a resolução de problemas analíticos clássicos: determinação espectrofotométrica de misturas de zircônio e háfnio

The determination of zirconium-hafnium mixtures is one of the most critical problem of the analytical chemistry, on account of the close similarity of their chemical properties. The spectrophotometric determination proposed by Yagodin et al. show not many practical applications due to the significant spectral interference on the 200-220 nm region. In this work we propound the use of a multivariate calibration method called partial least squares ( PLS ) for colorimetric determination of these mixtures. By using PLS and 16 calibration mixtures we obtained a model which permits determination of zirconium and hafnium with accuracy of about 1-2% and 10-20%, respectively. Using conventional univariate calibration the inaccuracy of the determination is about 10-25% for zirconium and above 57% for hafnium.

Métodos analíticos ultrasensíveis: lente térmica e técnicas correlatas

Among the emergent laser based spectrometric methods, thermal lensing and other photothermal techniques present a great potential for solving a variety of problems in the fields of chemistry, physics and biology. Their main advantages are high concentration sensitivity, sensibility to physical-chemical properties of the medium, excellent spatial resolution and noninvasive characteristics. In this article, theoretical principles, main applications and practical hints as well as fundamental limitations of these techniques will be carefully described. It is hoped that this will give the reader a clear picture of this field of investigation as well as provide to the ones who are not specialists in the area, the necessary background to understand, implement and use photothermal techniques. In the final sections the development frontiers of photothermal spectrometry will be discussed.

Avaliação dos métodos analíticos para a determinação de metabólitos do benzeno como potenciais biomarcadores de exposição humana ao benzeno no ar

Increasing attention is being paid to the use of biomarkers for determining the exposure of humans to air toxics. Biomarkers include the nonreacted toxic substance, their metabolites, or the reaction products of these toxics with naturally substances in the body. Significant progress has been made in the measurement of biomarkers during the past several years. Much of this progress has been because of the development of advanced analytical techniques for identification and quantification of the chemical species in complex matrix, such as biological fluids. The assessment of the potential cancer risk associated with exposure to benzene at occupational and non-occupational ambient is necessary because of the toxicological implications of this air pollutant. Thus, in this review, the analytical methodologies used to determine the benzene metabolites, in special, urinary muconic acid and S-phenylmercapturic acid, are described and several problems affecting the precision of these procedures are discussed. Finally, in view of the difficulty pointed out for selecting the more adequate biomarker, further studies to evaluate the human exposure levels to benzene should be done.

Utilização de filtro de transformada de fourier para a minimização de ruídos em sinais analíticos

Instrumental data always present some noise. The analytical data information and instrumental noise generally has different frequencies. Thus is possible to remove the noise using a digital filter based on Fourier transform and inverse Fourier transform. This procedure enhance the signal/noise ratio and consecutively increase the detection limits on instrumental analysis. The basic principle of Fourier transform filter with modifications implemented to improve its performance is presented. A numerical example, as well as a real voltammetric example are showed to demonstrate the Fourier transform filter implementation. The programs to perform the Fourier transform filter, in Matlab and Visual Basic languages, are included as appendices

Uso de métodos analíticos convencionados no estudo da autenticidade do óleo de copaíba

The acidity and ester index are suggested, as simple and cheap methods, adequate to be employed in the study of the authenticity of copaíba oil by small drugstores and export firms. The acidity index permits both the detection and the evaluation of the content of adulteration of copaíba oil. The ester index permits to know if the adulterant either contain ester compounds,as the case of fatty oils, or contain only non saponifiable compounds as is the case of ethyl alchool or mineral oil. The results of the aplication of the methods to eight commercial samples, of copaiba oil, where three samples were adultered, are coherent with those obtained by more sophisticated instrumental methods.

Le Cabinet de l'amateur et de l'antiquaire : revue des tableaux et des estampes anciennes, des objets d'art, d'antiquité et de curiosité

1861-1862.

Le Cabinet de l'amateur et de l'antiquaire : revue des tableaux et des estampes anciennes, des objets d'art, d'antiquité et de curiosité

Variante(s) de titre : Le Cabinet de l'amateur

Le Cabinet de l'amateur et de l'antiquaire : revue des tableaux et des estampes anciennes, des objets d'art, d'antiquité et de curiosité

1842 (T1).

Le Cabinet de l'amateur et de l'antiquaire : revue des tableaux et des estampes anciennes, des objets d'art, d'antiquité et de curiosité

1863 (A3,N25).

Le Cabinet de l'amateur et de l'antiquaire : revue des tableaux et des estampes anciennes, des objets d'art, d'antiquité et de curiosité

1845 (T4)-1846.

Le Cabinet de l'amateur et de l'antiquaire : revue des tableaux et des estampes anciennes, des objets d'art, d'antiquité et de curiosité

1844 (T3).