Hi Bhagya,

The product of the reaction, heteropolymolybdenum blue, has an absorption maximum near 750 nm, which is usually out of the range of interfering colors.  It is best, when ever possible, to measure absorption at the wavelength of maximum absorption for a chromophore.

Cheers,

John

@John, thank you very much. & I want to know the normal range of absorbance values (not the wave length) which is most accurate? 0.2-0.8 is the normal range we use. but in some articles, it is about 0.1-0.6. What is the correct one?

Hi Bhagya,

The standard curves for the Lowry method are only linear at low protein concentrations, between 0.05 - 0.5 mg/ml.  At present I do not know how that works out in absorbance units.   The absorbance will depend to some extent on how long you let the color develop.  Might I suggest using a series of solutions with varying concentration of BSA, and see when you lose linearity of absorption versus protein concentration.

I hope this is of some help.

Best,

John