Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
Klin Lab Diagn ; 63(5): 260-267, 2018.
Artículo en Ruso | MEDLINE | ID: mdl-30689317

RESUMEN

In organism, differences in physical chemical properties and physiological role of positional isomeric forms of triglycerides of fatty acids consumed with food are well known. The Raman spectroscopy to analyze there is possible to be applied. Both of these circumstances are to be considered and applied in resolving practical issues of dietetics, i.g., in detection of falsification and replacement of butter and spreads with palm oil, as well as in monitoring ratio of fatty consumed by patients with cardiologic and oncologic pathology. The purpose of study is to determine possibilities of analyzing positional fatty acids isomers specific for butter and palm oil using portable and operational spectrometers of absorption in near infrared range. The technique of projections on latent structures was applied to obtain calibrations of spectrometers to detect content of 7 regulated fatty acids and percentage of milk fat and palm oil in fat-oil mixtures according specters of Raman and near infrared range spectrometers. The possibility of identifying positional isomers of animal and vegetable triglycerides according Raman spectra was confirmed. Besides, it is established that efficiency of determining (reliability, accuracy and selectivity) the proportions of the above oils using both Raman spectra and near-infrared optical density spectra was much higher than when calculating the percentage of the same oils using the content of 7 fatty acids. This fact reflects sensitivity of near infrared range absorption spectra both to length of the carbon chain and degree of unsaturation (number of double bonds C=C) of fatty acids and positional isomeric forms of triglycerides. The obtained data are used in formulating technical requirements and conditions for application of portable near infrared range spectrometer for mass analysis of fat-oil products.


Asunto(s)
Mantequilla/análisis , Ácidos Grasos/análisis , Aceite de Palma/análisis , Análisis Espectral , Triglicéridos/análisis , Animales , Reproducibilidad de los Resultados
2.
Klin Lab Diagn ; 60(11): 13-20, 2015 Nov.
Artículo en Ruso | MEDLINE | ID: mdl-26999859

RESUMEN

The content of clinically important fatty acids and individual triglycerides in food and biological mediums are traditionally detected by gas and fluid chromatography in various methodical modifications. The techniques are hard-to-get in laboratories of clinical biochemistry. The study was carried out to develop procedures and equipment for operative quantitative detection of concentration of fatty acids, primarily palmitic saturated fatty acid and oleic mono unsaturated fatty acid. Also detection was applied to sums ofpolyenoic (eicosapentaenoic and docosahexaenoic acid) fatty acids in biological mediums (cod-liver oil, tissues, blood plasma) using spectrometers of short-range infrared band of different types: with Fourier transform, diffraction and combined scattering. The evidences of reliable and reproducible quantitative detection offatty acids were received on the basis of technique of calibration (regression) by projection on latent structures using standard samples of mixtures of oils and fats. The evaluation is implemented concerning possibility of separate detection of content of palmitic and oleic triglycerides in mediums with presence of water The choice of technical conditions and mode of application of certain types of infrared spectrometers and techniques of their calibration is substantiated


Asunto(s)
Ácidos Docosahexaenoicos/análisis , Ácido Eicosapentaenoico/análisis , Ácido Oléico/análisis , Ácido Palmítico/análisis , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Triglicéridos/análisis , Animales , Mantequilla/análisis , Calibración , Aceite de Hígado de Bacalao/química , Análisis de los Alimentos , Humanos , Margarina/análisis , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectroscopía Infrarroja por Transformada de Fourier/instrumentación
3.
Science ; 168(3936): 1210-4, 1970 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-17843589

RESUMEN

A considerable portion of the abyssal floor of the western North Pacific was already receiving pelagic sediment in late Jurassic time. Carbonate sediments were later replaced by abyssal clays as the basin deepened and bottom waters became more aggressive. The resulting facies boundary, which can be recognized on seismic profiles, is broadly transgressive; it ranges in age from mid-Cretaceous in the western Pacific to Oligocene in the central Pacific. Cherts are encountered at and below the major facies boundary and appear to have been formed by postdepositional processes.

4.
Science ; 180(4089): 952-4, 1973 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-17735923

RESUMEN

Deep sea drilling in the eastern Indian Ocean shows that the oceanic crust off Western Australia is approximately 140 million years old and becomes younger to the west; this dates the initial opening of the Indian Ocean.

5.
J Colloid Interface Sci ; 303(1): 159-63, 2006 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-16904681

RESUMEN

Petrols with different octane numbers, diesel fuel and solutions of crude oil in toluene have been studied by the methods of absorption spectroscopy, circular dichroism spectroscopy and correlation spectroscopy of scattered light. Circular dichroism signal was registered for crude oil solutions in the spectral ranges corresponding to the measured earlier resonance absorption of asphaltene solutions in toluene. We show that the optical activity of crude oil solutions is due to the aggregation of asphaltene molecules in one spectral range and is intensified with the aggregation of asphaltene molecules in another spectral range. Petrols have no optical activity. The optical activity registered for diesel fuel is possibly due to the aggregation of asphaltene molecules.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA