Comparison of different methods for the determination of the water content and the dry mass correction factor in various plant samples

1998 ◽  
Vol 360 (5) ◽  
pp. 601-604 ◽  
Author(s):  
S. Stegen ◽  
F. Queirolo ◽  
P. Ostapczuk ◽  
A. Groemping ◽  
M. Paz ◽  
...  
Keyword(s):  
Water Content ◽  
Correction Factor ◽  
Dry Mass ◽  
Mass Correction ◽  
Plant Samples

scholarly journals Determination of Aucubin and Catalpol in Plantago Species by Micellar Electrokinetic Chromatography

2004 ◽  
Vol 59 (1-2) ◽  
pp. 27-31 ◽  
Author(s):  
Renata Jurišić ◽  
Željko Debeljak ◽  
Sanda Vladimir-Knežević ◽  
Jadranka Vuković
Keyword(s):  
Micellar Electrokinetic Chromatography ◽  
Iridoid Glycosides ◽  
Dry Mass ◽  
Hot Water ◽  
Water Extraction ◽  
Electrokinetic Chromatography ◽  
Hot Water Extraction ◽  
Plant Samples ◽  
Related Compounds

Micellar electrokinetic chromatography (MEKC) was used for the separation and determination of two iridoid glycosides, aucubin and catalpol, in several Plantago species growing in Croatia: P. altissima L., P. argentea Chaix, P. coronopus L., P. holosteum Scop. (subsp. depauperata, subsp. holosteum and subsp. scopulorum), P. lagopus L., P. lanceolata L., and P. maritima L. Hot water extraction (HWE) was applied for the isolation of iridoid substances. Significant differences appeared between the iridoid contents in the examined species. The yield of aucubin and catalpol was up to 0.27% and 1.81% of the dry mass of the leaves, respectively. Besides aucubin and catalpol, two related compounds were determined in the plant samples.

scholarly journals Determination of water content in infant formula

2019 ◽  
pp. 37-42
Keyword(s):  
Water Content ◽  
Infant Formula ◽  
Reference Method ◽  
Dry Mass ◽  
Karl Fischer Titration ◽  
Karl Fischer ◽  
Different Types ◽  
The Stability ◽  
Water Contents

Water is one of the most important constituents of food, very important to be accurately quantified. Furthermore, water content affects the stability and shelf life of food. The evaluation of most chemical parameters is based on dry mass and many methods use heating which result in losing all volatile compounds, including water. Also, it is much harder to extract all of water if we have a complex matrix. Regarding this, the aim of this study was to determine water content in different infant formula by various methods. For examination of water content in three different types of infant formula three different techniques were used (oven sample processor, drying oven and halogen drying) and compared to classical Karl Fischer titration with two different solvents. Each sample was measured in ten probes, and classical Karl Fischer titration was used as a reference. The results showed that the reference method was the best regarding speed of measurement, amount of sample needed and obtained water contents (3.01- 4.35%), followed by Karl Fischer in boiling methanol (2.80-4.30), oven sample processor (2.96-4.23%), halogen drying (2.74-4.03%) and drying oven (2.38-3.52). Methods using heating could not remove all water from the sample within a reasonable time.

STEM measurement of subcellular water distributions

1993 ◽  
Vol 51 ◽  
pp. 568-569
Author(s):  
R.D. Leapman ◽  
S.Q. Sun ◽  
S-L. Shi ◽  
R.A. Buchanan ◽  
S.B. Andrews
Keyword(s):  
Water Content ◽  
Internal Standard ◽  
Dry Weight ◽  
Dry Mass ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Bulk Water ◽  
Inelastic Electron ◽  
Scanning Transmission ◽  
Annular Dark Field

Recent advances in rapid-freezing and cryosectioning techniques coupled with use of the quantitative signals available in the scanning transmission electron microscope (STEM) can provide us with new methods for determining the water distributions of subcellular compartments. The water content is an important physiological quantity that reflects how fluid and electrolytes are regulated in the cell; it is also required to convert dry weight concentrations of ions obtained from x-ray microanalysis into the more relevant molar ionic concentrations. Here we compare the information about water concentrations from both elastic (annular dark-field) and inelastic (electron energy loss) scattering measurements.In order to utilize the elastic signal it is first necessary to increase contrast by removing the water from the cryosection. After dehydration the tissue can be digitally imaged under low-dose conditions, in the same way that STEM mass mapping of macromolecules is performed. The resulting pixel intensities are then converted into dry mass fractions by using an internal standard, e.g., the mean intensity of the whole image may be taken as representative of the bulk water content of the tissue.

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