ABBOTT LABORATORIES
INTEROFFICE CORRESPONDENCE
Date:
2/13/12
From:
Louis Salvati
Subject: Validation of LC/MS Determination of Total B
6
, B
1
, and B
2
Using an
Enzymatic Preparation.
Background
Although internal methodologies are available for the determination of the
fortified forms of pyridoxine (PYR), thiamin (THI), and riboflavin (RIB); Abbott
Nutrition does not currently have a method for the determining the total content of these
three nutrients. While the overwhelming majority of each vitamin in Abbott Nutrition’s
products comes from the fortified form, some comes from the natural ingredients used in
the products. Natural ingredients such as milk contain two forms or pyridoxine:
pyridoxal (PAL) and pyridoxamine (PAM) as well as phosphorylated versions of these
two forms. Milk also contains the fortified form of riboflavin with two phosphorylated
analogs and the fortified form of thiamin with two phosphorylated analogs. Government
regulations in certain countries require the total content to be determined. This method
would also be a useful internal research tool.
In order to assay the inherent nutrient content that is bound in the sample, some
form of matrix digestion is needed; and additionally, since those forms are
phosphorylated, a dephosphorylating agent is also necessary. The matrix digestion can be
carried out by strong acid and heat, or enzymatically. A potential procedure was proposed
by C. Hasselmann
1which used papain, and alpha-amylase to break down the sample
matrix to free bound nutrients. Acid phosphotase is also added to dephosphorylate the
nutrients. The separation developed is based loosely on work done by Hong Zhang
2using an Acquity BEH C18 column (2.1 mm x 50 mm, 1.7 um) and a 20 mM ammonium
formate and methanol gradient. The separation is done in less than 7 minutes and is
illustrated in Figures 1 and 2.
A limited sample group consisting only of milk-based infant formulas was chosen
for this validation because milk based ingredients are the dominant source of the inherent
vitamins. The goal was to first establish a solid basis using the most affected sample
type. Two standard reference materials were analyzed along with a commercial infant
formula and a placebo infant formula not fortified with these nutrients. Samples spiked
with the phosphorylated forms of each nutrient were tested; however, the spiking levels
8
BVit-02
FOR ERP USE ONLY
DO NOT DISTRIBUTE