# Beer-Lambert Law Question watch

1. Hi all,

I have no idea how to work this out...

"The molar extinction coefficient of NADH is 6.22 x 103 M-1

During an LDH assay using lactate and NAD+ as the substrates, the absorbance of the reaction mixture at 340nm increased from 0.05 to 0.6.

What was the concentration of NADH at the end of the assay? "

I assume this is a Beer-Lambert Law Question, but I don't know how to use the Beer Lambert Law to work this out. The Molar Extinction Coefficient is 6.22 x 103
and the absorbance is now 0.6. I have no idea how to rearrange the Beer-Lambert Law to make C the subject.

A = ebc
0.6 = 6.22 x 103 . . .

The only other thing I can think of doing is making a graph?
2. (Original post by AshEntropy)
Hi all,

I have no idea how to work this out...

"The molar extinction coefficient of NADH is 6.22 x 103 M-1

During an LDH assay using lactate and NAD+ as the substrates, the absorbance of the reaction mixture at 340nm increased from 0.05 to 0.6.

What was the concentration of NADH at the end of the assay? "

I assume this is a Beer-Lambert Law Question, but I don't know how to use the Beer Lambert Law to work this out. The Molar Extinction Coefficient is 6.22 x 103
and the absorbance is now 0.6. I have no idea how to rearrange the Beer-Lambert Law to make C the subject.

A = ebc
0.6 = 6.22 x 103 . . .

The only other thing I can think of doing is making a graph?
Are you not given a path length? Once you have that, you have all parameters except c, which is what you're trying to calculate
Are you not given a path length? Once you have that, you have all parameters except c, which is what you're trying to calculate
The path length is 1cm

I just don't know how to rearrange the formula to work out C
4. (Original post by AshEntropy)
The path length is 1cm

I just don't know how to rearrange the formula to work out C
Oh thank you very much

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