© 2012 AOAC INTERNATIONAL
Detector program: Dionex ED 50 with special
gold electrode cell SP4270
t, s
E, V
Delete this table. Obsolete
0.0
+0.05
0.2
+0.05
0.4
+0.05
0.41
+0.75
0.6
+0.75
0.61
–0.15
1.0
–0.15
W
1
2
p
d
1
p
d
1
A
1
V
2
Table 2011.18B. PAD settings with gold electrode
Analog
range
1 uC
Detector program: Dionex
ICS3000 or ICS 5000PED
t, s
E,V
E, V
0.0
0.00
retention time should be 11 to 13 min (depending on the type of
switching valve used and the individual analytical column).
(
a
)
Concentration of working standards
.
C = W
1/0.05
1/10
A /V
A /V
W
1 1
2 2
= W
2
A /V
A /V
0.0 +0.10
0.
52
0
+
0.
01
0
0.40 +0.10
0.41 -2.00
1 1
2 2
0.
4251
+
02
.
80
0
where C
is the concentration of the working standard solution in
0.
5943
+0.
86
0
0.
6044
–0.
71
0
0.
85
0
–0.
71
0
milligrams per liter; W is the weight, in milligrams, of myo-inositol
standard weighed; 0.05 is the dilution volume of the stock standard
in liters; 1/10 is the intermediate standard dilution (10 to 100 mL);
is the aliquot of intermediate standard used, in milliliters; V is
Integration period
0.
23
0–0.
54
0
s
the dilution volume of the working standard in milliliters; A is the
aliquot of working standard used, in milliliters, if applicable; and
is the dilution volume of the working standard in milliliters, if
Integration period 0.20–0.40 s
set of standards has been injected, a control sample and up to 14
samples can be injected before another set of standards should be
injected.
(
4
)
System shutdown.—
After all samples and standards have
been analyzed, inject one vial of water to clean out the autosampler
needle and tubing. Store the analytical columns in mobile phase
[0.12% (30 mM) sodium hydroxide]. Turn off the electrochemical
cell. Flush the pump heads with water to remove sodiumhydroxide.
F. Calculations
Before calculating myo-inositol concentrations in samples,
compare the myo-inositol standard peaks with the myo-inositol
sample peaks and confirm that there are not any interfering
compounds and that the myo-inositol sample peak areas or heights
are within the range of the myo-inositol standard peak areas or
heights. The concentration of myo-inositol cannot be calculated if
there are interferences or if the separation is poor. The myo-inositol
a
pplicable.
(
b
)
Preparation of standard curve.—
For each working standard
concentration, average the peak areas or heights from each
two consecutive sets of standards. Prepare a standard curve by
performing linear least squares (regression) on the concentrations
versus the averaged peak areas or heights. A standard curve must
have a correlation of at least 0.999 to be considered acceptable for
sample calculations.
At each working standard level, the peak areas or heights
of standards injected before and after a set of samples must not
increase or decrease by more than 7%.
(
c
)
Calculation of myo-inositol in samples and controls
.—The
concentration of myo-inositol in a prepared sample or control is
extrapolated from the standard curve prepared above. From the
diluted, prepared sample concentration, the product concentration
can be calculated:
C = (C
D )/S
where C is the concentration of myo-inositol in the product sample
or control in milligrams per kilogram; C is the concentration of
myo-inositol in the prepared sample or control in milligrams per
liter; D is the dilution volume in milliliters; and S is the sample
weight in grams.
Note
: For each set of samples, the control result must be within 3
standard deviations of the control mean.
G. Validation Data
Note: SLV and MLT data from the ERP checklist will be added
to this section. Data tables will be added by September 19.
References:
J. AOAC Int
.
95
, 937(2012); AOAC SMPR 2011.007,
J. AOAC Int
.
95
, 295(2012)
