7
In the examples given above the analytes were retained under both RPLC and HILIC modes. However, when operating
under RPLC conditions the analytes were only marginally retained and not fully resolved. When working in HILIC the
analytes are baseline resolved with the added advantage of a considerably lower back pressure.
The resulting elution order in HILIC is roughly the opposite of that observed in a reversed phase separation [14],
as in the following chromatograms:
Elution under HILIC conditions
HILIC
P=250 bar
RPLC
P= 326 bar
Column:
Accucore HILIC
, 2.6 μm
150 × 4.6 mm
Mobile Phase:
92:8 acetonitrile:100mM ammonium
formate, pH 3.2
Flow Rate:
3.5 mL/min
Inj.Volume:
10 μL
Temp.:
40 °C
Detection:
UV at 230 nm
Sample:
1. epinephrine
2. norepinephrine
Column:
Accucore aQ
, 2.6 μm
100 × 2.1 mm
Mobile Phase:
5 mM ammonium formate, pH 3.2
Flow Rate:
0.6 mL/min
Temp.:
30 °C
Inj.Volume:
2 μL
Detection:
UV at 230 nm
Elution under RPLC conditions
0.0
1
2
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4
5
Time (Minutes)
0.0
Time (min)
1
2
3
4
5
1
2
0.0
1
2
3
4
5
Time (Minutes)
0.0
Time (min)
1
2
3
4
5
1
2
