This seems so simple, but I can't figure out what I'm missing.
I'm doing acetyl substitution analysis on starch. The procedure I'm using was written ages ago by someone who isn't with the company anymore and I see now I should have double checked it earlier, but anyway...
The calculation for DS is given as
Degree of substitution = 162 * % acetyl
4300 – (43 x % acetyl)
But I got some literature the other day and they give the calculation as
162 x %A/[4300-(42x%A)]
Since the molecular weight of an acetyl group (-O-C-CH3
) is 43
what's with the 42?
Once we've all stopped snickering about the Hitchhiker's reference can someone help me out? Thanks much.