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Instrument Conditions
1.
Gradient
–
Fructans are eluted using a gradient of NaOH and sodium acetate at 1.0 mL/min as per figure 1-1 & table 1-
2 below. Column and detector compartment are maintained at 20 °C.
a.
Please note that a Carbopac PA1 guard is used for this procedure rather than the borate trap used in part 2 for
quantitative fructan determination. Therefore if same day analysis is desired two separate HPAEC-PAD
systems are needed.
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 3 retention time standards. Samples are bracketed
with standards after every 6 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.
Figure 1-1
Qualitative ID Gradient
Table 1-2
Qualitative ID Gradient*
Time (min) Flow (ml/min) %C (500 mM NaOH) %D (300 mM NaOAc) Curve
0
1.0
8.0
25.0
NA
0
1.0
8.0
25.0
5
40.0
1.0
8.0
92.0
5
45.0
1.0
8.0
92.0
5
45.1
1.0
8.0
25.0
5
55.0
1.0
8.0
25.0
5
*B line not used in this separation, remainder to make up 100% is from line “A” (lab water)
Fos-04 (February 2016)
FOR ERP USE ONLY
DO NOT DISTRIBUTE