Hello,

I am trying to MDA equivalents as described by Hodges (1999), but I am having trouble determining if I am doing the proper calculations.

The authors provide the following equation: MDA Equivalents (nmol ·ml^-1 )=[(A532-A600)/155000]10^6 (from page 2 of article)

And they also provide absorbance values and MDA equivalent values (which were presumably calculated using the above equation)

For spinach + TBA (from table 3. on page 5 of article)

A532 = 0.013

A600 = 0.001

MDA Equivalent = 16.772 ± 2.535

However, when I try and set up this equation in excel and input their provided numbers, I do not get the same end result, or seemingly even close. I am unsure where I may be going wrong, or how else to manipulate the equation.

I have attached the source article and my excel calculations.

I am starting out using the author's reported dataset because I want to verify that I am implementing and interpreting this equation properly before I attempt to apply it to my own absorbance readings.

Many thanks for any consideration and input you may be able to provide!

Note: there are several modifications listed in the article, but right now I am interested in the basic procedure (credited to Heath and Packer 1968) and the first modification only (credited to Du and Bramlage 1992). The excel file should help clarify.