hi

i dont understand exactly what you think with formula. but normally you use a calibration curve with iron ion to measure this activity, you just have to measure the optical density of your sample within test and make the projection on the calibration curve. ABs = a [Extract] + b

Dear Urmila check the

....attachment hope it is of some help

You should mention how will you express your result in FRAP assay. What will be your standard? Is it ascorbic acid or Trolox? Please mention your procedure of FRAP assay.

I used freshly prepared aqueous ascorbic acid solutions of 100, 500, and 1000 µM (equivalent to 200, 1000, and 2000 µM FRAP) as standard. Absorbance values were converted to mM ascorbic acid equivalent per 100 g of fresh weight of the whole plant or leaves or roots (mM AAE/100 g FW).

Dear Urmila, Oyais Chat has right about calculating your results. I have question to you, because I determine FRAP activity in essential oils, and I wonder if you check the absorbance of your frap reagent, because my is negative which means that something is wrong. But what is it if I've done FRAP reagent just before measurements ,according to the literature? Please give me any suggestions.

I used freshly prepared extract and standard (FeSo4) solution of mg/ml concentration then how i calculate the result in mM or µM?

Agnieszka Brodowska.....Pls tell me that when you add FRAP reagent in your sample than it is separated in two layer or not?

No, it was one layer. Today, I' ve done for the third time frap reagent and I made a mistake in preparing 40mM HCl solution. And finally the mixuture was straw coloured, after adding to samples blue colour appeared so the reduction reaction occurred. I think it is better to expressed results in mM, but uM are correct as well.

Which solvent did you use to your standard solution (FeSO4)?

yes ...i use FeSO4 as a standard

To evaluate the free radical scavenging potential of various extracts from whole plant  with the help of two in-vitro antioxidant  models are carried out for total antioxidant activity (phosphomolybdic acid method), ferric-reducing antioxidant  potential (FRAP) assay and estimation of total flavonoids. Ascorbate is used as standard and positive control for total antioxidant  activity (phosphomolybdic acid method), ferric-reducing antioxidant potential (FRAP) methods.Benzie and Strain (1996) or its modification can be adopted for the FRAP assay.  Chemicals and stock preparations can be used like this. The stock solutions include 300 Mm acetate buffer, Ph 3.6, 10 Mm TPTZ (2, 4, 6-tripyridyl-S-triazine) solution in 40 mMHCl and 20 mMFecl3. 6H2O. The fresh working solution is prepared by mixing 25 ml acetate buffer, 2.5 ml TPTZ and 2.5 ml Fecl3 .6H2O. The temperature of the solution should raised to 37 0C before using. Plant extracts (0.15 ml) are  allowed to react with 2.85 ml of FRAP solution for 30 min in the dark condition. Readings of the colored product (Ferrous tripyridyltriazine complex) are noted at 593 nm. The standard curve diplay linear between 200  and 1000 µM Feso4. Results are expressed in µM (Fe (II) /g dry mass and compared with that of ascorbic  acid.

how to relate curve of FeSO4 and standard Ascorbic acid?

I ahve used FesO4 as standard..how to calculate FRAP value. pls help

Hi Everyone. Can someone help me with calculation On FRAP.

I have used FeSO4.7H2O as my standard. I managed to calculate the concentration in mM Fe. However, I need to express my answer in mM FE/g DW?

Can someone help me to explain how to calculate along with an example..

Thank you..

You can find useful answer from this link

https://www.researchgate.net/post/Can_anybody_explain_me_how_to_calculate_FRAPFerric_Reducing_Antioxidant_Power_activity_from_standard_graph

Dear Oluwaseun, FRAP activity was expressed in term of Fe (II) equivalents...So in my view you need to draw standard curve of FeSO4.

Dear Oluwaseun, FRAP activity was expressed in term of Fe (II) equivalents...So in my view you need to draw standard curve of FeSO4.

Hi all,

i have slight confusion in plotting standard curve. I was wondering if we notice any color change when we add FRAP reagent to different concentration of Feso4. Mine does not.

Hi everybody,

How can I tranform mM of Fe to equvalent in Trolox ?

Thank you very much!

Ravi Kant Upadhyay Sir,

Results are expressed in µM (Fe (II) /g dry mass and compared with that of ascorbic  acid. what do you mean by the statement.

You have to divide sample changes from 0 minute to 4 minute by standard changes from 0 minute to 4 minute and multiply the answer with FRAP value of standard.

Can anybody better explain in excel file for better understanding .I am still not getting it well

Calculate the FRAP value of the samples using the equation obtained from the linear

regression of the standard curve substituted ΔA593 nm values for each sample.

FRAP (μM) = (ΔA593 nm – intercept) / slope