172 research outputs found
DEVELOPING THE METHODS OF FOOD PRESERVATIVES EXTRACTION FROM COMPLEX MATRICES FOR BIOASSAY PURPOSE
The presence of food additives in food products may be associated with the risk of their toxic effects on human body. Therefore, the study of approaches to testing their safety seems to be a particularly urgent task. The aim of this study was to determine the conditions for extracting food preservatives from the samples of preserved pureed vegetables for further bioassay of the extract obtained in the Allium test. Onion roots were used as a test object in this method. Two extraction methods of benzoic and sorbic acids added to pureed vegetables have been developed. Distilled water and acetone were used as extracting solutions. The extraction efficiency was evaluated on Shimadzu Prominence LC-20 liquid chromatograph (Japan) in the ultraviolet range, wavelength 235 nm (benzoic acid), 285 nm (sorbic acid). According to the results of studies using both water and acetone as extractants, the degree of preservatives extraction was approximately the same and quite high. In the quantitative calculation of the preservatives content in pureed vegetables, the value of the correction factor was 0.8. However, due to certain production characteristics of this product, i. e. the stage of cauliflower homogenization, obtaining an extract with acetone seems to be more acceptable for the Allium test conditions.The presence of food additives in food products may be associated with the risk of their toxic effects on human body. Therefore, the study of approaches to testing their safety seems to be a particularly urgent task. The aim of this study was to determine the conditions for extracting food preservatives from the samples of preserved pureed vegetables for further bioassay of the extract obtained in the Allium test. Onion roots were used as a test object in this method. Two extraction methods of benzoic and sorbic acids added to pureed vegetables have been developed. Distilled water and acetone were used as extracting solutions. The extraction efficiency was evaluated on Shimadzu Prominence LC-20 liquid chromatograph (Japan) in the ultraviolet range, wavelength 235 nm (benzoic acid), 285 nm (sorbic acid). According to the results of studies using both water and acetone as extractants, the degree of preservatives extraction was approximately the same and quite high. In the quantitative calculation of the preservatives content in pureed vegetables, the value of the correction factor was 0.8. However, due to certain production characteristics of this product, i. e. the stage of cauliflower homogenization, obtaining an extract with acetone seems to be more acceptable for the Allium test conditions
Modes of magnetic resonance of S=1 dimer chain compound NTENP
The spin dynamics of a quasi one dimensional bond alternating spin-gap
antiferromagnet Ni(CHN)NO(ClO) (abbreviated as NTENP) is
studied by means of electron spin resonance (ESR) technique. Five modes of ESR
transitions are observed and identified: transitions between singlet ground
state and excited triplet states, three modes of transitions between spin
sublevels of collective triplet states and antiferromagnetic resonance
absorption in the field-induced antiferromagnetically ordered phase.
Singlet-triplet and intra-triplet modes demonstrate a doublet structure which
is due to two maxima in the density of magnon states in the low-frequency
range. A joint analysis of the observed spectra and other experimental results
allows to test the applicability of the fermionic and bosonic models. We
conclude that the fermionic approach is more appropriate for the particular
case of NTENP.Comment: 11 pages, 11 figures, published in Phys.Rev.
Novel magnetic phases in a Gd2Ti2O7 pyrochlore for a field applied along the [100] axis
We report on longitudinal and transverse magnetisation measurements performed
on single crystal samples of Gd2Ti2O7 for a magnetic field applied along the
[100] direction. The measurements reveal the presence of previously unreported
phases in fields below 10 kOe in an addition to the higher-field-induced phases
that are also seen for H//[111], [110], and [112]. The proposed H-T phase
diagram for the [100] direction looks distinctly different from all the other
directions studied previously.Comment: 4 pages, 5 figure
- …