Im doing biochemical analysis (phenols, flavonoids, and antioxidant) for wheat seeds, after i did all the steps i measured the absorbance of samples using spectrophotometer, so the question is how we can calculate the content of GAE for phenols, or quercetin for flavonoids in mg/g sample from the Abs?
Or how we can convert from abs to mg/g for both phenols (gallic acid standard) and flavonoids (quercetin standard)?
1st Step: Draw the graph of standard values and you will get an equation y=mx+c and the R square value which should be close to 1 eg 0.998/0.992
Using this equation calculate the values placing the absorbance in place of y so you will get the value of x for each absorbance.
This value is in the x microgram concentration of extract.
Now to calculate the value /g we will use the formula
value × 1000/concentration taken
will give you the value in mg/g
From the calibration curve of standard we obtain
Y = mx + C and r2 value close to 0.999
With the help of this we can calculate value of X in microg/g
After this multiply value with 1000.
The simplest way is to plot the absorbance versus m/g of gallic acid (quercetin). The result will be in mg/g equivalents of gallic acid or of quercetin
Plot the graph of absorbance vs concentration of standard (galic and quercetin). Then a linear equation: y = mx + c. Concentration in mg/g GAE or QE is calculated by C = x (v/m). where v = volume of sample used, m= mass of sample w/v used.
- Badges
- Science topic