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Michael Margolies

Formula for determination of MDA concentration in fish tissue?

Dirk Kok  Follow

Dear Femi,
That means  extinction coefficient is 156000 M-1cm-1 (that is156 mM-1cm-1)
OD of your sample is 0.189
0.189 = 156 x 1 x Concentration
Concentration = 0.189/156  = 0.00121154 mM = 1.21154 microM = 1211.54 nM
1211.54 nM (that means you have 1211.54 nmoles in 1000 ml). That means you have  1.21154 nmoles/ml
(as you have taken one ml of two ml solution for your assay , you need to multiply accordingly) (This is based on the information furnished by you along with your original question)

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Charlie  Follow

i am getting confusion  in calculating of nmol/ml MDA in to nmol MDA /g tissue. i used okhawa method 

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Benita Nwachukwu  Follow

Dear Prof. Pardha-Saradhi
Sir, you are such a wonderful person with a good heart. You have really solve my problem and simplify the whole thing for me. Thanks so much sir.  

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Chris Harper  Follow

Dear Femi,
Can you let me know the reference of protocol you are following? Authors might have given extinction coefficient of MDA-TBA complex/abduct based on their protocol. If you follow the protocol of Kwon et al., where 0.5% TBA in 20% TCA is used, then you can use the extinction coefficient of malondialdehyde-TBA at 532 nm given in their paper, which is 155 mM-1 cm-1. Extinction coefficient will vary based on reaction conditions (which include the way you are preparing reagents).
In case if extinction coefficient is 'X' mM-1 cm-1 then concentration of MDA in a sample that is showing absorbance of 0.189 would be
1/0.189 micromoles/ml [if path length is one cm and in most of the spectrophotometric measurements it is one (unless it is otherwise specified)].
I am sure you are aware that one mM MDA will have one micromole MDA/ml [one mM solution will have one mmole in 1000 ml i.e. 1000 micromoles in 1000 ml (i.e. one micromole/ml)].
If extinction coefficient is not stated in the paper, you need to prepare MDA standard curve.

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Chaise Murphy  Follow

I am very much thank full to Pro.P.Pardha Saradhi for detail information on MDA calculation. I also got cleared about this problem. Sir thank you very much.

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Carolyn Barnett  Follow

Dear Feli, You should also devise by your protein concentration if you want your MDA expressed in nmoles/mg of proteins.

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Brian Burnside  Follow

Dear Femi,
That means  extinction coefficient is 156000 M-1cm-1 (that is156 mM-1cm-1)
OD of your sample is 0.189
0.189 = 156 x 1 x Concentration
Concentration = 0.189/156  = 0.00121154 mM = 1.21154 microM = 1211.54 nM
1211.54 nM (that means you have 1211.54 nmoles in 1000 ml). That means you have  1.21154 nmoles/ml
(as you have taken one ml of two ml solution for your assay , you need to multiply accordingly) (This is based on the information furnished by you along with your original question)

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Andrew Wiltshire  Follow

Dear prof Pardha Saradhi
Sir what is the formula for TBA calucation whether it is
TBA =Absorbance /155*weight of sample

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Allan Emery  Follow

Dear Alok,
you need to elaborate on what sort of confusion you have. If you are in Delhi, you may visit my lab in University of Delhi.

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Dalton Mendeleve  Follow

 Hello sir...its really elaborated answer for the MDA conc calculation.. P.Pardha-Saradhi sir may you please mentioned here when wen got MDA nmol/ml then how it convert in nmol/g or nmol/mg?
may please...
Thank you

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Andy Carnduff  Follow

Dear Prof. Pardha-Saradhi
Sir, lipid peroxidation was assayed by measuring malondialdehyde (MDA) formation as described by Sharma and Krishnamurthy (1968). extinction coefficient is 1.56 x 10 5 (raise to power of 5) M-1cm-1. 

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Bobby Tatro  Follow

Dear Femi,
It’s my pleasure. Thanks for your compliments.
GOOD LUCK

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