Liquid chromatographic analysis of vitamin B6 in reconstituted infant formula: collaborative study.
A liquid chromatographic (LC) method was validated for the determination of total vitamin B6 in infant formula. Total vitamin B6 was quantified by converting the phosphorylated and free vitamers into pyridoxine. Pyridoxine was determined by ion pair reversed-phase LC with fluorescence detection. The method was subjected to an AOAC collaborative study involving a factory-manufactured, milk- and soy-based infant formula. Each was spiked at 3 concentrations in the range of 0-1 microg/g and sent as blind duplicate to participant laboratories. Nine laboratories returned valid data which were statistically analyzed for outliers and precision parameters. The repeatability relative standard deviation (RSD(r)) ranges were 2.0-4.0 and 3.5-5.9% for fortified milk- and soy-based formulas, respectively. The reproducibility relative standard deviation (RSD(R)) ranges were 8.2-8.4 and 6.7-11.2% for fortified milk- and soy-based formulas, respectively. HORRAT values ranged from 0.42 to 0.53, indicating that the precision of the method is acceptable. The mean RSD(r):RSD(R) values were 0.60 and 0.55 for milk- and soy-based formulas, respectively. As expected, RSDs for the unfortified samples were higher, but their HORRAT values (0.81 and 2.06) helped define a realistic limit of quantitation as 0.05 microg/g. Recovery data were quantitative and varied between 81.4 and 98.0% (mean = 89.8%) for each of 6 spiked materials.
Mann
Dudley L
DL
U.S. Food and Drug Administration, Southeast Regional Laboratory, 60 Eighth St, NE, Atlanta, GA 30309, USA.
Ware
George M
GM
Bonnin
Evelyn
E
Eitenmiller
Ronald R
RR
Barna
Eva
E
Christiansen
Scott
S
De Borde
Jean Luc
JL
DeVries
Jonathan
J
Gilliland
Pamela
P
Hemmer
Jane
J
Kalman
Andras
A
Konings
Erik
E
Levin
David
D
Salvati
Louis
L
Woollard
David
D
D000818:Animals; D002138:Calibration; D002417:Cattle; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods; D005504:Food Analysis / Q000379:methods*; D005526:Food, Formulated; D006038:Glyoxylates / Q000737:chemistry; D006801:Humans; D007225:Infant Food / Q000032:analysis*; D041943:Infant Formula; D007231:Infant, Newborn; D007501:Iron / Q000378:metabolism; D000432:Methanol / Q000737:chemistry; D008892:Milk; D041942:Soy Milk; D013696:Temperature; D013997:Time Factors; D025101:Vitamin B 6 / Q000737:chemistry* / Q000378:metabolism
D006038:Glyoxylates; D025101:Vitamin B 6; D007501:Iron; C031150:glyoxylic acid; D000432:Methanol