INFLUENCE OF WINE PRODUCTS SAMPLE VARIETY ON THE SORBINIC ACID MASS CONCENTRATION DETERMINATION BY THE SPECTROPHOTOMETRIC METHOD

Author(s):  
R.P. Tochilina ◽  
◽  
I.N. Pashkova ◽  
T.S. Sklepovich ◽  
◽  
...  
Author(s):  
R. P. Tochilina ◽  
Т. S. Sklepovich ◽  
M. A. Zakharov

In the production of low-alcohol and non-alcoholic beverages, the use of preservatives is allowed, including benzoic acid (BК) and its salts. Standard methods based on high performance liquid chromatography are used to control the content of this preservative. This work presents the results on the determination of benzoic acid in samples of low-alcohol and non-alcoholic products by the spectrophotometric method. Research has been carried out to establish the optimal wavelength when measuring the optical density of benzoic acid solutions. A calibration characteristic has been constructed to determine the mass concentration of benzoic acid, which makes it possible to determine its concentration in the range from 10 mg/dm3 to 500 mg/dm3 of benzoic acid, taking into account dilution. Metrological data have been obtained for constructing a calibration characteristic for the determination of benzoic acid in low-alcohol and non-alcoholic products. It is shown that the results of the determination of this preservative in the indicated products by the spectrophotometric method are comparable with the analogous results obtained using standard methods based on high performance liquid chromatography. The research results became the basis for the developed Methodology for measuring the mass concentration of sorbic and benzoic acids in low-alcohol and non-alcoholic products by the spectrophotometric method. The developed technique allows measuring the mass concentration of benzoic acid in low-alcohol and non-alcoholic products containing only benzoic acid. The spectrophotometric method for determining the mass concentration of BA is a less costly method for determining this preservative in a product than the currently used method of high-performance liquid chromatography, does not require special expensive equipment, additional consumables and specially trained personnel..


2011 ◽  
Vol 29 (3) ◽  
pp. 227-235 ◽  
Author(s):  
Y. Qing ◽  
D. Caili ◽  
W. Yefei ◽  
T. Engao ◽  
Y. Guang ◽  
...  

Author(s):  
M. Haider ◽  
B. Bohrmann

The technique of Z-contrast in STEM offers the possibility to determine the local concentration of macromolecules like lipids, proteins or DNA. Contrast formation depends on the atomic composition of the particular structure. In the case of DNA, its phosphorous content discriminates it from other biological macromolecules. In our studies, sections of E. coli, the dinoflagellate Amphidinium carterae and Euglena spec. cells were used which were obtained by cryofixation followed by freeze-substitution into acetone with 3% glutaraldehyde. The samples were then embedded either in Lowicryl HM20 at low temperature or in Epon at high temperature. Sections were coated on both sides with 30Å carbon.The DF- and the inelastic image have been recorded simultaneously with a Cryo-STEM. This Cryo-STEM is equipped with a highly dispersive Electron Energy Loss Spectrometer. With this instrument pure Z-contrast can be achieved either with a Filtered DF-image divided by the inelastic image or, as is used in this paper, by dividing the conventional DF-image by an inelastic image which has been recorded with an inelastic detector whose response is dependent on the total energy loss of the inelastically scattered electrons.


1949 ◽  
Vol 21 (2) ◽  
pp. 315-315 ◽  
Author(s):  
N McDonald ◽  
Jacqueline Thompsett ◽  
J Mead

Sign in / Sign up

Export Citation Format

Share Document