There are many protocols available for calculating pigment  c on tent  using  the well known and widely used text :the chemistry and biochemistry  of plant pigments, by Goodwin, 1965. we have been using this text for years with excellent results.

Dear Puriya.

 You can see these articles:

ftp://saleskalab.eebweb.arizona.edu/Field%20Course%202009/Summer%20PIRE%20Course%202009/Course%20Readings/Readings%20for%20Amazon-PIRE%20Field%20Course/Sims_RSE_2002.pdf

Extract the fresh material with 80% acetone, then centrifuge the  extract for 5min. take the   clear extract and measure the absorbance at 645 and 663nm.using spectrophotometer. then calculate the concentration of chlorophyll a,b and total chlorophyll using the following  formula: mg /l chlorophyll a=12.7xO.D.663-2.69xO.D.645

mg/l chlorophyll b= 22.9xO.D.645-4.68xO.D.663

mg/l total chlorophyll=20.2xO.D.645+18.2xO.D.663

Then you  get rid of the liter by dividing the product on1000,you will be left with mg,then you could  express the results as you like, for example mg per 100 mg fresh weight.

Thanks to all RG friends for the best answers.