Does anyone know dubois (1951) formula for calculation of sugar in plant extract? I have already calculated soluble sugar content in the sample using the standard graph developed using pure glucose.
Biochemical calculations
CALCULATIONS for many biochemical like protein, sugars, free amino acids with appropriate standard.
Amount of test sample taken = 0.5g
Total volume of the supernatant = 10ml
Volume of the sample taken for experiment = 1.0ml
Test sample Absorbance of 1.0ml =____OD units
Find out standard absorbance (OD) units and Standard absorbance value (micro gram) through standard graph.
Calculations
Test sample absorbance x STD. Absorbance Value (micro g) / STD absorbance units = ------- micro gram
micro g/1000 = -------mg
i.e., 1.0ml sample contains = ____mg
10ml supernatant contain ____mg x 10 = _____mg
I.e. 0.5g test sample contain = -----mg
1g of test sample contain = ---mg x 2 = -------mg / gram test sample
Have you come across this paper? I just searched to find this. Check out
Article A method for routine measurements of total sugar and starch ...
Dear Priyanka,
There are a lot of published paper which use and describe the formula of Dubios:
http://www.pakbs.org/pjbot/PDFs/45(S1)/03.pdf
http://prr.hec.gov.pk/Chapters/1074S-3.pdf
file:///C:/Users/Mehdi%20H/Downloads/96851-252092-1-PB%20(1).pdf
http://naldc.nal.usda.gov/naldc/download.xhtml?id=57440&content=PDF
See below material and method section of a paper:
Total Soluble Sugar Content (mg/g) Total soluble sugar was determined based on the method given by Dubois (1951). Fresh leaves (0.1g) were added with 5 ml of 80 % ethanol to test tubes, placed in water bath, and heated for 1 hour at 80 ºC. Then, 1 ml of the sample extract was taken in another set of test tubes and mixed with 1 ml each of 18 % phenol and distilled water, and then allowed to stand at room temperature for an hour. Finally, 5 ml of sulphuric acid was added and the whole mixture was vortexed. The absorbance was read at 490 nm wavelength on the UV spectrophotometer. Ethanol 80 % was used as blank sample
Absorbance of sample x K value x Dilution factor Soluble sugars
soluble sugar= -------------------------------------------------------------------------------------------
Weight of fresh tissue
Dubois, M., K. Gilles, J.K. Hammiltron, P.A. Robers and F.Smith, 1951. A colorimetric method for the determination of sugars. Nature, 168:167-168.
Dear Priyanka
Mehdi gives all information you wish. One paper related to your query herewith attached.
http://www.nature.com/nature/journal/v168/n4265/abs/168167a0.html
Colorimetric Method for Determination of Sugars and Related Substances by
MICHEL DUBOIS, K.A.GILLES,J.K HAMILTON, P. A. REBERS,and FRED SMITH
Division of Biochemistry, University of Minnesota, St.Paul,Minn. Simple
sugars, oligosaccharides, polysaccharides,and their derivatives, including the methyl ethers with free or potentially free reducing groups, give an orange-
yellow color when treated with phenol and concentrated sulfuric acid. The
reaction is sensitive and the color is stable. By use of phenol-sulfuric acid reaction,
a method has been developed to determine submicro amounts
of sugars and related substances. In conjunction with paper partition chromatography the method is useful for the determinationo f the composition of polysaccharides
and their methyl derivatives. A standard curve is prepared for each sugar by taking concentration of sugar on X axis and absorbance after color development of y axis.
Aa =su[sugar], Aa A=+sc, [sugar]
css=A′-A′/as-as'
Biochemical calculations
CALCULATIONS for many biochemical like protein, sugars, free amino acids with appropriate standard.
Amount of test sample taken = 0.5g
Total volume of the supernatant = 10ml
Volume of the sample taken for experiment = 1.0ml
Test sample Absorbance of 1.0ml =____OD units
Find out standard absorbance (OD) units and Standard absorbance value (micro gram) through standard graph.
Calculations
Test sample absorbance x STD. Absorbance Value (micro g) / STD absorbance units = ------- micro gram
micro g/1000 = -------mg
i.e., 1.0ml sample contains = ____mg
10ml supernatant contain ____mg x 10 = _____mg
I.e. 0.5g test sample contain = -----mg
1g of test sample contain = ---mg x 2 = -------mg / gram test sample
Sure, Calculations is same for All Quantitative Estimation of Biochemicals. All the best 😊
With regards
Most protocol I see for total sugars using phenol sulfuric acid assay make use of solid sample. my sample is in a liquid form (Palm oil mill effluent), How do 1 go about it? Do adopt same procedure as in Dubois 1951? also do I have to also carry out the HCL hydrolysis part? or just go straight to add the phenol and sulfuric solution to my sample?
Dear friends, pls refer my pervious answer for all the queries, thank you
Hello! Does it is possible to use Dubois method for analysis the non liquid sample? Example: pallet or raw sample? Thanks in advance.
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