method’s applicability as written?
ile using or regarding use of the method?
Study Director Response
he data for the
he free myo-inositol
See Question 1, Comment 6, Study Director Response.
d in a fume hood. 2)
olution, or use more
A reference to perform sample cleanup in a fume hood can be added to the
method. A very important step in the hydrolysis procedure that was in AOAC
First Action 2011.18 Journal manuscript (J AOAC Int., Vol 95, No.4, 2012) was
accidently omitted from the MLT protocol and the online 2011.18 method
document. After samples are removed from the oven ~ 10 mL of water should
be added to samples before adding NaOH.
Study Director Response
In Study Director's experience, these storage conditions are acceptable.
During the MLT, study directors discovered that there were significant
differences between the ovens used by study participants. Even though all
oven temperature were set at 110°C, samples did not appear to be exposed to
the same amount of heat based on improvements in recoveries when oven
temperatures were increased. Some participants with very low
phosphatidylinositol recoveries were asked to increase oven temperatures to
improve hydrolysis of phosphatidylinositol. If this method is approved as a final
action method, hydrolysis conditions will need to adjusted.
Study directors corrected an error in the method document after the original
MLT study protocol was issued.
clean up is well
a lab for routine
ould be use.
’s necessary to use
tuations will be
for the HPLC column
be very long (the
rge?)
Study Directors are willing to work with laboratory to determine why no
inositol peaks were detected.
A statement can be added to the method to allow for a helium sparge option.
The comment "Area where temperature fluctuations will be minimal
throughout the run" is to minimize changes in detector response due to air
temperature fluctuations, but there is not a laboratory air temperature
requirement. Maybe it would be more appropriate to change this comment to
"maintain the electrochemical detector cell at a constant temperature
throughout the run".
