AOAC OMB Final Action Recommendation (December 2019)-2016.14

FOS-03 FOR WORKING GROUP/ERP USE ONLY DO NOT DISTRIBUTE

and re-equilibrated for 10 min with 5.1 mM sodium hydroxide before the next injection (see

table below for details).

Post column addition - 300 mM sodium hydroxide is introduced at a flow rate of 0.6 mL/min

via a T-piece between the column and the PAD detector.

Injection – A single 20 μL injection is made of each sample test solution. At the start of each

series two blank (water) injections of 20 μL are made to stabilise the system, followed by a

20 μL injection of standard solution. A 20 μL injection of the standard solution is made after

every 6 sample injections and at the end of the series.

Retenetion times – Retenetion times are controlled by comparing that of the standard with

that of the sample. Typically fructose elutes at around 36 minutes.

Method for LC determination of fructose

Time (min)

% A (NaOH, 300mM)

% B (water)

Comment

0

1.7

98.3

Start

45

1.7

98.3

Finish isocratic elution

45.1

100

0

Start column wash

55.0

100

0

End column wash

55.1

1.7

98.3

Start re-equilibation

65.0

1.7

98.3

End re-equilibration

G. Calculations

The concentration of the fructose standard is calculated as follows: