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37
R
1
and R
2
ca. 5.2 and 4.9 Reducing
ends
12
M and G, both
α
and
β
-form
For each peak we obtain a corresponding peak area or intensity (denoted I).
The sequence parameters are obtained as follows:
F
G
= I
A
/[I
A
+ (I
B3
+ I
B4
)] = I
A
/I
tot
B3+B4 is the sum of all M’s. Next (by definition):
F
M
= 1 - F
G
Further:
F
GG
= I
C
/I
tot
F
GGM
= I
B1
/I
tot
F
MGM
= I
B2
/I
tot
F
MG
= F
GM
= I
B3
/I
tot
F
MM
= I
B4
/I
tot
The remaining parameters are easily obtained from those above:
F
GGG
= F
GG-
F
GGM
N
G>1
= [F
G
- F
MGM
]/F
GGM
In practical situation at worksheet is used for the calculations. Only the NMR
peak areas (A, B
1
, …) need to be entered to obtain all sequence parameters.
1.2.11. Chain
length
(DP
n
)
from NMR
Separate signals from the reducing ends enable simple calculation of the
number average degree of polymerization (DP
n
), the average number of
monomers (monosaccharides) per chain:
DP
n
= (n
M
+ n
g
)/n
red.ends
= I
tot
/(I
R1
+ I
R2
)
12
Only seen in samples with very low DP