Determination of Myo-Inositol - AOAC International

INFANT FORMULA AND ADULT NUTRITIONALS
Schimpf et al.: Journal of aoac international Vol. 95, no. 4, 2012 1
Determination of Myo-Inositol (Free and Bound as
Phosphatidylinositol) in Infant Formula and Adult Nutritionals
by Liquid Chromatography/Pulsed Amperometry with
Column Switching: First Action 2011.18
Karen Schimpf and Linda Thompson
Abbott Laboratories, 3300 Stelzer Rd, Columbus, OH 43219
steve Baugh
AOAC INTERNATIONAL, 481 N. Frederick Ave, Suite 500, Gaithersburg, MD 20877
Myo-inositol is a 6-carbon cyclic polyalcohol also
known as meso-inositol, meat sugar, inosite,
and i-inositol. It occurs in nature in both free
(myo-inositol) and bound (inositol phosphates and
phosphatidylinositol) forms. For the determination
of free myo-inositol, samples are mixed with dilute
hydrochloric acid to extract myo-inositol and
precipitate proteins, diluted with water, and filtered.
For the determination of myo-inositol bound as
phosphatidylinositol, samples are extracted with
chloroform, isolated from other fats with silica
SPE cartridges, and hydrolyzed with concentrated
acid to free myo-inositol. Prepared samples are
first injected onto a Dionex CarboPac PA1 column,
which separates myo-inositol from other late-eluting
carbohydrates. After column switching, myo-inositol
is further separated on a CarboPac MA1 column
using a 0.12% sodium hydroxide mobile phase;
strongly retained carbohydrates are eluted from the
PA1 column with a 3% sodium hydroxide mobile
phase. Eluant from the CarboPac MA1 analytical
column passes through an electrochemical detector
cell where myo-inositol is detected by pulsed
amperometry using a gold electrode. The method
showed appropriate performance characteristics
versus selected established standard method
performance requirement parameters for the
determination of myo-inositol: linear response;
repeatability (RSD r) of 2%; and intermediate
precision (RSD ir) of 2.5%. Instrument LOD and LOQ
Submitted for publication January 24, 2012.
The method was approved by the Expert Review Panel on Infant
Formula and Adult Nutritionals as First Action. See “Standards News,”
(2011) Inside Laboratory Management, September/October issue.
The AOAC Stakeholder Panel on Infant Formula and Adult
Nutritionals (SPIFAN) invites method users to provide feedback
on the First Action methods. Feedback from method users will
help verify that the methods are fit for purpose and are critical
to gaining global recognition and acceptance of the methods.
Comments can be sent directly to the corresponding author.
Corresponding author’s e-mail: karen.schimpf@abbott.com
DOI: 10.5740/jaoacint.CS2011_18
were 0.0004 and 0.0013 mg/100 mL, respectively,
and correspond to a free myo-inositol quantitation
limit of 0.026 mg/100 g and a phosphatidylinositol
quantitation limit of 0.016 mg/100 g. Correlation with
the reference microbiological assay was good. The
proposed method has been accepted by the Expert
Review Panel as an AOAC First Action Method,
suitable for the routine determination of myo-inositol
in infant formula and adult nutritionals.
Myo-inositol is a 6-carbon cyclic polyalcohol
(Figure 1) that occurs as anhydrous, hydroscopic
crystals. Myo-inositol has a sweet taste, is soluble in
water, and is slightly soluble in alcohol. It is insoluble in ether
and other organic solvents. Aqueous solutions are neutral. It has
a molecular weight of 180.16, a melting point of 225–227°C,
and is optically inactive.
There are nine possible stereoisomeric forms of inositol.
Seven are optically inactive or “meso.” Two optically active
forms, the racemic form, and several cis, trans-isomers occur
naturally. Myo-inositol is the most widely distributed inositol
isomer and is present in all living cells. It occurs in nature
in both free (myo-inositol) and bound (inositol phosphates
and phosphatidylinositol) forms. Fruits, beans, grains, and
nuts are all good sources of myo-inositol. Myo-inositol is
essential for the growth of many mammalian cells. Although
free myo-inositol is not essential for humans, the abnormal
metabolism of myo-inositol by the body has been associated
with diabetes mellitus and chronic renal failure.
AOAC Official Method 2011.18
Myo-Inositol (Free and Bound as
Phosphatidylinositol) in Infant Formula
and Adult Nutritionals
Liquid Chromatography/Pulsed Amperometry
with Column Switching
First Action 2011
The liquid chromatography method with electrochemical
(pulsed amperometry) detection (PAD) allows for the
quantitation of myo-inositol in infant, pediatric, and adult
nutritional formulas. The concentration of myo-inositol

2 Schimpf et al.: Journal of aoac international Vol. 95, no. 4, 2012
OH
OH
HO
OH
OH
Figure 1. Myo-inositol. Figure 1. Myo-inositol
OH
is calculated by comparison with standards of known
concentration. Total myo-inositol, as defined by AOAC standard
method performance requirement (SMPR) 2011.007 (1), can be
calculated by adding the free myo-inositol and myo-inositol
bound as phosphatidylinositol data.
The method was validated for the quantitation of free
myo-inositol only. Repeatability was determined from triplicate
analyses performed on the same day. Intermediate precision
was determined from replicate determinations performed over
multiple days. Accuracy was determined by comparison to a
reference microbiological assay and expressed as the percentage
of HPLC results relative to microbiological results. Instrument
LODs and LOQs were determined statistically from injections
of low-level standards.
Caution: Refer to Material Safety Data Sheets (MSDS) of
chemicals prior to use and follow safe handling
procedures and the suggested personal protective
equipment.
A. Apparatus
(a) Analytical balance.—Minimum weighing capacity of at
least 0.0001 g.
(b) Centrifuge.
(c) Desiccator.
(d) N-evap.—With water bath or equivalent.
(e) Oven.—Capable of maintaining 110°C.
(f) pH meter.—With pH 4 and 7 buffers.
(g) Stir plate.—Multiposition with stir bars.
Table 2011.18A. Instrument operating conditions
Pump 1 pressure limit 2000 psi
Pump 1 mobile phase 0.12% (30 mM) NaOH
Pump 1 flow rate 0.4 mL/min
Pump 2 pressure limit 2000 psi
Pump 2 mobile phase 3% (750 mM) NaOH
Pump 2 flow rate 0.4 mL/min
Injection volume 20 µL
Myo-inositol retention time 11–13 min
Run time 25 min
t, min
Switching valve configuration time table
Configuration
0.00 1 (see Figure 2011.18A)
1.50 2 (see Figure 2011.18B)
11.50 1 (see Figure 2011.18A)
Electrochemical
Detector
MA1 Guard and
Analytical Columns
Pump 1
PA1 Guard Column
(h) Tubing.—PEEK or Teflon 0.007–.01 in. id.
(i) Vacuum manifold.
(j) Vortex mixer.
(k) HPLC system.—Corrosion-resistant autosampler, isocratic
pump (2), 6-port switching valve, and pulsed amperometry
detector with a gold electrode. Autosampler capable of injecting
20 µL.
(l) Columns.—Dionex CarboPac MA1 (4 × 250 mm) P/N
44066, MA1 (4 × 50 mm) P/N 44067, and PA1 (4 × 50 mm)
P/N 43096, or equivalent (www.thermofisher.com/dionex/).
B. Materials
(a) Beakers.—Assorted sizes.
(b) Centrifuge tubes.—50 mL with Teflon-coated caps.
(c) Syringe filters.—Nylon, 0.45 and 0.2 µm.
(d) Filter paper.—Whatman 2V or equivalent (www.
whatman.com).
(e) Erlenmeyer flasks.—50 or 125 mL or equivalent.
(f) Volumetric flasks.—Assorted sizes.
(g) Funnels.—Suitable for use with filter paper.
(h) Pipets.—Volumetric (Class A); assorted sizes.
(i) Solid-phase extraction (SPE) cartridges.—Silica, 1 g (J.T.
Baker P/N 7086-07, www.avantormaterials.com) or equivalent.
(j) Syringes.—1 mL disposable and 25 mL gas-tight glass
with 4 in. stainless steel needles.
C. Chemicals and Solvents
(a) Acetic acid.—Glacial, ACS.
(b) Chloroform.—High-purity, HPLC grade.
(c) Diethyl ether.—Anhydrous, HPLC grade.
(d) Drierite (desiccant).—Anhydrous calcium sulfate,
8 mesh.
(e) Helium.—Zero grade or equivalent.
(f) Hexane.—HPLC grade.
(g) Hydrochloric acid.—Concentrated (36–38%), ACS.
(h) Distilled or deionized laboratory water.
Waste
Pump 2
Figure 2011.18A. Switching valve configuration 1.
Figure 2011.18B. Switching valve configuration 2.

Table 2011.18B. PAD settings with gold electrode
Analog range 1 uC
Detector program: Dionex PED t, s E, V
0.0 0.00
0.50 0.00
0.51 +0.80
0.59 +0.80
0.60 –0.70
0.80 –0.70
Integration period
Detector program: Dionex ED 50 with
0.30–0.50 s
special gold electrode cell SP4270 t, s E, V
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
Integration period 0.20–0.40 s
(i) Meta-phosphoric acid.—ACS.
(j) Methanol.—HPLC grade.
(k) Myo-inositol.—USP reference standard, official lot; store
desiccated. See standard label for purity.
(l) Sodium acetate trihydrate or sodium acetate.—
Anhydrous, ACS.
(m) Sodium chloride.
(n) Sodium hydroxide.—50% (w/w), low carbonate form.
D. Preparation of Reagents and Standard Solutions
All solutions can be scaled up or down for convenience
provided good laboratory practices are observed. Solutions can
be stored at 2–30°C in tight, inert containers otherwise noted.
(a) Myo-inositol stock standard solution (approximately
2000 mg/L).—Accurately weigh approximately 0.100 g
myo-inositol and quantitatively transfer to a 50 mL volumetric
flask. Dilute to volume with water. Mix well. Store refrigerated.
Expiration: 3 months.
(b) Myo-inositol intermediate standard solution
(approximately 200 mg/L).—Dilute 10.0 mL stock standard to
100 mL with laboratory water and mix well. Discard after use.
(c) Myo-inositol working standard solutions (approximately
4, 2, 1, 0.5, 0.2, and 0.05 mg/L).—Dilute 2.0, 1.0, and
0.5 mL myo-inositol intermediate standard to 100 mL
with laboratory water (4, 2, and 1 mg/L). Dilute 0.5 mL
myo-inositol intermediate standard to 200 mL with laboratory
water (0.5 mg/L). Dilute 4 and 1 mL of the 0.5 mg/L myoinositol
working standard to 10 mL with laboratory water (0.2
and 0.05 mg/L). Expiration: 2 weeks.
(d) Hydrochloric acid, 0.5%.—Add 1.25 mL concentrated
hydrochloric acid to approximately 200 mL water in a 250 mL
volumetric flask. Dilute to volume with water and mix well.
Expiration: 6 months.
Schimpf et al.: Journal of aoac international Vol. 95, no. 4, 2012 3
(e) Sodium chloride, 1 N.—Dissolve 5.8 g sodium chloride
and dilute to 100 mL with water. Expiration: 1 month.
(f) Sodium hydroxide, 0.12% or 30 mM (Pump 1).—Quickly
weigh 4.8 (±0.1) g of 50% sodium hydroxide into a 2000 mL
volumetric flask containing approximately 1900 mL water.
(Note: It is important that the sodium hydroxide does not
absorb carbon dioxide from the air.) Swirl to mix well. Dilute to
volume with water and mix well. Expiration: 1 month.
(g) Sodium hydroxide, 3.0% or 750 mM (Pump 2).—Quickly
weigh 120 (±3) g of 50% sodium hydroxide into a 2000 mL
volumetric flask containing approximately 1900 mL water.
(Note: It is important that the sodium hydroxide does not
absorb carbon dioxide from the air.) Swirl to mix well. Dilute to
volume with water and mix well. Expiration: 1 month.
(h) 6% Metaphosphoric acid.—Weigh 6.0 g metaphosphoric
acid into a 100 mL volumetric flask. Dissolve and dilute to
volume with laboratory water. Mix well. Store refrigerated.
Expiration: 1 week.
(i) Phosphatidylinositol extraction solutions.—
(1) Chloroform:methanol (2:1).—Mix 60 mL chloroform and
30 mL methanol.
(2) Hexane:diethyl ether (80:20).—Mix 80 mL hexane and
20 mL diethyl ether.
(3) Hexane:diethyl ether (50:50).—Mix 50 mL hexane and
50 mL diethyl ether.
(4) Methanol:chloroform:water (75:15:10).—Mix 75 mL
methanol, 15 mL chloroform, and 10 mL water.
E. Sample Preparation and Extraction
(a) Sample preparation for free myo-inositol
determinations.—Prepared samples that are constantly stored
at 1–8°C in closed containers are stable for up to 5 days. After
5 days, samples must be prepared again.
Figure 2011.18C. Examples of typical chromatograms
of (a) myo-inositol standard, (b) free myo-inositol in
SRM 1849, (c) myo-inositol from phosphatidylinositol in
SRM 1849.
(a)
(b)
(c)

4 Schimpf et al.: Journal of aoac international Vol. 95, no. 4, 2012
Table 1. Free myo-inositol validation data—
intermediate precision, mg/100 g
HPLC method
Day
Product type 1 2 3
Hypoallergenic infant formula RTF 8.11 8.06 8.17
n 3 3 3
RSD, % 3.64 5.01 3.40
Soy-based infant formula powder 31.1 31.8 30.9
n 3 3 3
RSD, % 2.49 0.327 1.35
Specialty infant formula RTF 19.7 18.9 19.0
n 3 3 3
RSD, % 1.60 0.976 1.73
Milk-based infant formula RTF 4.36 4.43 4.38
n 3 3 3
RSD, % 1.91 4.26 0.784
Very low-fat infant formula powder 125 126 122
n 3 3 3
RSD, % 1.46 3.37 1.19
Free amino acid-based infant formula
powder
65.5 65.0 64.9
n 3 3 3
RSD, % 1.56 1.20 2.78
Pediatric nutritional beverage 10.3 10.5 11.1
n 3 3 3
RSD, % 2.02 1.00 4.19
Adult nutritional beverage 91.6 92.3 NA a
n 4 4
RSD, % 1.35 1.22
a NA = No data generated.
Table 3. Free myo-inositol validation data—accuracy data
Product type
HPLC method a ,
mg/100 g
Table 2. Free myo-inositol validation data—
intermediate precision, mg/100 g
Product type n Avg.
Hypoallergenic infant formula RTF 9 a
Soy-based infant formula powder 9 a
Specialty infant formula RTF 9 a
Milk-based infant formula RTF 20 b
Very low-fat infant formula powder 9 a
Free amino acid-based infant formula powder 9 a
Pediatric nutritional beverage 9 a
Adult nutritional beverage 8 c
a Intralaboratory triplicate analyses on 3 days.
HPLC method
RSD,
%
8.13 3.58
31.3 1.89
19.2 2.22
4.39 2.53
125.0 2.72
65.0 1.82
10 4.25
91.9 1.25
b Intralaboratory single, duplicate, or triplicate analyses on 9 days.
c Intralaboratory quadruplicate analyses on 2 days.
Thoroughly mix or stir products prior to sampling. For
liquid products, accurately weigh 0.5 to 5 g (±10%) of product
into a 100 mL volumetric flask and record the weight to the
nearest 0.0001 g. For powdered products that do not require
reconstitution, accurately weigh 0.25 to 1.5 g powder into a
100 mL volumetric flask and record the weight to the nearest
0.0001 g. Add approximately 10 to 15 mL laboratory water
to the volumetric and swirl or stir to completely dissolve the
powder. For powdered products that are not homogeneous at
the subgram level, reconstitute following the product label
instructions and accurately weigh 0.5 to 5 g reconstituted product
into a 100 mL volumetric flask. Record the weight to the nearest
0.0001 g. Add enough 0.5% hydrochloric acid to each sample
to adjust the sample pH to 4.5 ± 0.2 and swirl to mix. Allow the
volumetric flasks to set a minimum of 2 min. Dilute to volume
with laboratory water and mix well. Filter samples through
Whatman 2V filter paper into 125 mL Erlenmeyer flasks. (Note:
Although some samples will filter cloudy, the filtrates can still
be used.) Filter an aliquot of sample filtrate through a 0.45 µm
syringe filter into an autosampler vial.
(b) Sample preparation for phosphatidylinositol
determinations.—(1) Extraction.—Weigh 4 g (±10%) liquid
Microbiological method b ,
mg/100 g HPLC/micro, %
Hypoallergenic infant formula RTF 8.13 7.4 110
Soy-based infant formula powder 31.3 37.0 84.5
Specialty infant formula RTF 19.2 19.0 101
Milk-based infant formula RTF 4.39 3.7 119
Very low-fat infant formula powder 125.0 140.0 89.2
Free amino acid-based infant formula powder 65.0 62.0 105
Pediatric nutritional beverage 10.6 11.0 96.6
Adult nutritional beverage 91.9 83.0 111
a Multiple intralaboratory analyses on multiple days.
b Single analyses.

or reconstituted powder product or 1 g (±10%) homogeneous
powder into a 50 mL centrifuge tube and record the weight to
the nearest 0.0001 g. Add 10 mL methanol and stir for at least
20 min. Add 20 mL chloroform and stir for at least 5 min. If
large clumps form when chloroform is added, cap tube and
shake well to mix sample. Add 5 mL 6% metaphosphoric acid
and 1 mL 1 N NaCl and mix well. Centrifuge. Remove the
bottom chloroform layer and evaporate with nitrogen in a 60°C
water bath.
(2) Sample cleanup.—Condition a 1 g silica SPE cartridge
with 6 mL hexane. Dissolve residue in bottom of centrifuge
tube in 1 mL chloroform:methanol (2:1). Quantitatively transfer
dissolved residue to the conditioned silica SPE cartridge. Rinse
SPE cartridge with 3 mL hexane:diethyl ether (80:20) and discard
the eluant. Rinse SPE cartridge with 3 mL hexane:diethyl ether
(50:50), 4 mL methanol, and 4 mL methanol:chloroform:water
(75:15:10) and collect all eluants in a single 50 mL centrifuge
tube. Evaporate eluants collected from SPE cartridge with
nitrogen in a 60°C water bath.
(3) Hydrolysis.—Add 40 µL concentrated acetic acid and
2 mL concentrated hydrochloric acid to residue in centrifuge
tube from the sample cleanup step. Tightly cap tube. Heat in a
110°C oven for 2 h. Cool. Dilute mixture with approximately
10 mL H 2O and then add 1.25 mL 50% (w/w) sodium hydroxide.
Transfer sample to a 50 mL volumetric flask and dilute to
volume with water. Filter an aliquot of sample filtrate through a
0.45 µm syringe filter into an autosampler vial.
(c) HPLC analysis.—(1) See Tables 2011.18A and B for
instrument operating conditions and PAD settings, respectively.
(2) Instrument startup.—The HPLC system should be
located in an area where temperature fluctuations will be
minimal throughout the run.
Prepare mobile phases. Helium sparge mobile phases
Schimpf et al.: Journal of aoac international Vol. 95, no. 4, 2012 5
and/or pressurize mobile phase reservoirs. If necessary, clean
and polish the gold working electrode. Turn on the detector
and pump mobile phase over the columns at a flow rate of
0.40 mL/min for at least ½ h to equilibrate the system. Verify
that the detector is stable before beginning an analysis. Inject
20 μL of the most concentrated standard at least 5 times and
note the peak areas or heights. If the system is equilibrated,
the RSD of the peak areas or heights of the last three standard
injections should be ≤2.0%.
(3) Standard and sample analysis.—Once the system has
equilibrated, inject one standard at each concentration. After
a 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 sodium hydroxide.
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. See Figure 2011.18C for examples of typical
chromatograms. The concentration of myo-inositol cannot
be calculated if there are interferences or if the separation is
poor. The myo-inositol retention time should be 11 to 13 min
(depending on the individual analytical column).
(a) Concentration of working standards.
Table 4. Free myo-inositol and myo-inositol from phosphatidylinositol data, mg/100 g
Product type n
SRM 1849 9 a
Myo-inositol from
phosphatidylinositol
Free
myo-inositol
Total (free + phosphatidyl
bound) myo-inositol
Myo-inositol from
phosphatidylinositol, % RSD, %
0.909 41.3 42.2 2.15 5.62
Hypoallergenic infant formula RTF Not detected 8.87 8.87 0
Hypoallergenic infant formula powder Not detected 69.1 69.1 0
Milk-based infant formula RTF 3 b
0.428 3.83 4.26 10.1 1.91
Milk-based infant formula powder 3 b
2.81 31.4 34.2 8.21 1.09
Soy-based infant formula RTF 3 b
0.995 4.05 5.05 19.7 1.46
Soy-based infant formula powder 3 b
11.3 31.9 43.2 26.1 2.05
Specialty infant formula RTF 3 b
0.416 27.5 27.9 1.49 0.60
Specialty infant formula powder 3 b
1.67 mg/100 g 208.0 209.7 0.80 2.69
Lactose-free infant formula RTF 3 b
0.333 3.90 4.23 7.86 0.76
Lactose-free infant formula powder 3 b
0.258 31.7 32.0 0.81 8.12
Specialty infant formula powder 3 b
1.51 mg/100 g 132.0 133.5 1.13 2.13
Rice starch infant formula RTF 3 b
0.318 4.13 4.45 7.15 5.97
Rice starch infant formula powder 3 b
0.233 33.1 33.3 0.70 4.72
Milk-based infant formula RTF 3 b
0.672 4.60 5.27 12.7 8.92
Milk-based infant formula powder 3 b
1.75 37.2 39.0 4.50 4.20
Pediatric nutritional beverage 3 b
0.751 12.4 13.2 5.71 2.08
a Intralaboratory triplicate analyses on 3 days.
b Intralaboratory triplicate analyses on 1 day.

6 Schimpf et al.: Journal of aoac international Vol. 95, no. 4, 2012
C W = W × 1/0.05 × 1/10 × A 1/V 1 × A 2/V 2
= W × 2 × A 1/V 1 × A 2/V 2
where C W is the concentration of the working standard solution
in 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); A 1 is the aliquot of intermediate
standard used, in milliliters; V 1 is the dilution volume of the
working standard in milliliters; A 2 is the aliquot of working
standard used, in milliliters, if applicable; and V 2 is the dilution
volume of the working standard in milliliters, if applicable.
(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 p = (C d × D 1)/S
where C p is the concentration of myo-inositol in the product
sample or control in milligrams per kilogram; C d is the
concentration of myo-inositol in the prepared sample or control
in milligrams per liter; D 1 is the dilution volume in milliliters;
and S is the sample weight in grams.
Total myo-inositol, as defined by AOAC SMPR 2011.007 (1),
can be calculated by adding the free myo-inositol and myoinositol
bound as phosphatidylinositol data.
Note: For each set of samples, the control result must be
within three standard deviations of the control mean.
Reference: J. AOAC Int. 95, (future issue)
Results and Discussion
During validation, the average repeatability was 2.0% RSD
and the intermediate precision was 2.5% RSD, as summarized
in Tables 1 and 2. Accuracy was determined by comparison to a
reference microbiological assay as detailed in Table 3 (2). The
instrument LOD and LOQ of the method were estimated to be
0.0004 and 0.0013 mg/100 mL, respectively, and correspond to
a free myo-inositol quantitation limit of 0.026 mg/100 g.
Although this method has not been fully validated for the
quantitation of myo-inositol bound as phosphatidylinositol,
some data have been generated and are summarized in Table 4.
The phosphatidylinositol quantitation limit has been estimated
to be 0.016 mg/100 g.
References
(1) AOAC SMPR 2011.007 (2012) J. AOAC Int. 95, 295. http://
dx.doi.org/10.5740/jaoac.int.11-0443
(2) Atkin, L., Schultz, A., Williams, W., & Frey, C. (1943) Ind.
Eng. Chem. Anal. Ed., 15, 141–144. http://dx.doi.org/10.1021/
i560114a022