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equilibrated with 50 mM NaOH for 15 minutes (see Figure 2-1 below). Column and detector compartment are maintained at 20
°
C.
2.
Injection –
A single 4 µL injection of each sample test solution is made. At the start of each sequence, 6 precision injections are
made to ensure that system is stable, followed by the 4 levels of working standard. Samples are bracketed with working
standards after every 13 injections. Autosampler is maintained at 10
°
C.
3.
Electrochemical detector parameters –
This method utilizes the carbohydrate triple waveform referred to in Thermo/Dionex
Tech Note 21, Waveform B (4).
Note this waveform is not appropriate for disposable gold electrodes!
The reference electrode
is set to AgCl mode.
4.
Retention times –
Typically fructose elutes around 10-11 minutes and glucoheptose around 16-18 minutes (see figure 2-2 below).
Figure 2-1
Quantitative Fructan Determination Gradient
Figure 2-2
Working standard chromatogram
Calculations
1.
Fructose Stock Standard –
Concentration is calculated as follows:
FOS-04
FOR ERP USE ONLY
DO NOT DISTRIBUTE