31 / 41
FOR EXPERT REVIEW PANEL USE ONLY
NOT FOR DISTRIBUTION
1
Expert Review Panel for Infant Formula and Adult Nutrition
Evaluation of Method - 2012.20
Title:
Determination of Choline in Infant Formula and Adult Nutritionals by Ion Chromatography with
Suppressed Conductivity Detection
Author:
Jeff Rohrer
Recommendation:
1.
Six samples in the MLT study were analyzed by 11 laboratories in duplicate (n = 22). Three of
them were RTF (one infant formula and two adult nutritionals) and the remaining 3 were the
powdered samples (one adult nutritional and two infant formulas).
2.
All the results (n=22) from all the laboratories were used in final statics to determine RSDr and
RSDR for all the three RTF samples and one of the powdered sample (one of the infant formula
sample).
3.
The results from one of the laboratory were considered outlier for the powdered adult
nutritional sample (milk based, Choline = 3.83 mg/100)g and were not used in the final
statistics calculation to determine RSDr and RSDR. Thus for this sample results from only 10
labs (all duplicates, n=20) were used in determination of RSDr and RSDR.
4.
The results from two of the laboratories were considered outlier for one of the powdered
infant formula sample (milk based, average Choline = 16.4 mg/100g) sample and were not used
in the final statistics calculation to determine RSDr and RSDR. Thus for this sample results from
only 8 labs (all duplicates, n=16) were used in determination of RSDr and RSDR.
5.
RSDRs of two of the samples out of three with choline concentration in 2-20 mcg/100 g range
(Powdered samples) were below <15% as required by the SMPR. One of the sample (adult
nutritional milk based) with concentration of 3.83 mg/100g gave RSDR of 30.6
%.
6.
RSDRs of two of the samples out of three with choline concentration in 20-100 mcg/100g range
(RTF samples) were below <10% as required by the SMPR. One of the RTF sample (Infant
formula milk based) with concentration of 21.3 mcg/100g provided RSDR of 15.3%.
7.
I do recommend the method for final action though two of the samples gave RSDR beyond the
SMPR required range if ERP agrees with my following justification. One of the sample (adult
nutritional milk based) with concentration of 3.83 mg/100g provided RSDR of 30.6
%.
The
choline level in the sample is close to LOQ of the method and some times expected to provide
higher RSDR.
The Infant formula milk based RTF with concentration of 21.3 mcg/100g