Biology Reference
In-Depth Information
in this context DV Chl(ide)
b
(E498 F666) refers to the magnitude of the Soret
excitation maximum of authentic DV Chl(ide)
b
at 498 nm, when the excitation
spectrum is recorded at an emission wavelength of 666 nm, etc.
...
The mean
k
and
K
values of 20 determinations for DV and MV Chl(ide)
b
amounted to
k
5
¼
0.0144;
k
6
¼
1.4382;
k
7
¼
0.4345
23.9631
0.0419
0.0026;
k
8
¼
0.0763;
K
3
¼
0.9819;
K
4
¼
0.9818. By substitution
for the values of
k
6
,k
8
,K
3
,
and
K
4
, Eqs. (
3.69
) and (
3.70
) transform into:
2.3038
DV Chl
ð
ide
Þ
b
ð
E498 F666
Þ¼
1
:
0184
ð
E498 F666
Þ
0
:
0425
ð
E475 F666
Þ
(3.72)
and
ð
Þ
b
ð
Þ¼
:
ð
Þ
:
ð
E498
F
666
Þ:
(3.73)
MV Chl
ide
E475 F660
1
0185
E475 F666
0
4421
3.7.6 Conversion of the DV and MV Chl(ide) b Soret
Excitation Ratios into DV and MV Chl(ide) b
Concentrations
Conversion of the net Soret excitation ratios to authentic concentration ratios was
achieved exactly as was described for DV and MV Chl(ide)
a
by reference to a
standard calibration curve. The calibration curve was constructed by:
(a) mixing authentic MV and DV Chl(ide)
b
in known proportions,
(b) by recording the required 77
K spectra on every mixture,
(c) by calculating the ratio of the experimental, net MV/net DV Soret
(d) excitation amplitudes for every mixture, with the help of Eqs. (
3.72
)and(
3.73
),
and finally,
(e) by plotting the authentic MV/DV Chl(ide)
b
ratios, on the abscissa, against the
experimental MV/DV ratio of the net Soret excitation amplitudes on the ordinate.
Under our instrumental conditions, for experimental Soret excitation ratios equal
to or smaller than 10.50, such a plot yielded a straight line with an intercept of
0.3806, a slope of 3.4392, and a correlation coefficient of 0.9974. At experimental
Soret excitation ratios greater than 10.50, the curve exhibited an ordinate intercept
of 3.1081, a slope of 2.0138, and a correlation coefficient of 0.9974.
The reliability of Eqs. (
3.72
) and (
3.73
) in determining the proportion of MV and
DV Chl(ide)
b
in mixtures of the two tetrapyrroles amounted to 0.63
5.79 % and
0.75
5.79 %, respectively as displayed below in Table
3.11
.
Search WWH ::
Custom Search