Effect of Reversed Phase Column on Elution Volume

Connection of the reversed phase column (RSpak DE-613) to RSpak KC-811 makes it possible to separate phosphoric acid, which is eluted earlier, from other organic acids.

Substance Elution Volume (mL)
DE-613
KC-LG
+ KC811 x 2
KC-LG
+ DE-613
+ KC-811 x 2
Oxalic acid
3.0
10.5
13.5
Maleic acid
4.2
11.4
15.6
Phosphoric acid
3.0
11.4
14.4
alpha-Ketoglutaric acid
3.2
11.5
14.7
Pyruvic acid
4.0
12.3
16.3
Citric acid
5.0
12.3
17.3
D-Glucuronic acid
3.3
12.3
15.6
Isocitric acid
5.0
12.6
17.6
Tartaric acid
3.8
13.0
16.8
Gluconic acid
3.4
13.5
16.9
Malonic acid
5.3
13.6
18.9
trans-Aconitic acid
15.7
13.7
29.4
Glyoxylic acid
3.7
14.0
17.7
Malic acid
5.1
14.1
19.2
Succinic acid
8.6
16.8
25.2
Glycolic acid
4.3
17.0
21.3
Lactic acid
5.5
17.5
23.0
Itaconic acid
15.7
17.6
33.3
Fumaric acid
16.9
17.8
34.7
beta-Hydroxypropionic acid
5.0
18.3
23.3
Formic acid
4.7
18.7
23.4
Uric acid
6.9
19.4
26.3
Acetic acid
6.3
20.4
26.7
Mesaconic acid
43.4
20.7
64.1
Adipic acid
30.2
21.1
51.3
Levulinic acid
11.5
21.2
32.7
L-Pyroglutamic acid
5.5
21.4
26.9
Propionic acid
12.8
23.9
36.7
CO32-,HCO3-
7.8
25.7
33.5
Isobutyric acid
32.3
26.5
58.8
n-Butyric acid
32.6
28.5
61.1
Isovaleric acid
Not eluted
32.9
Not eluted
n-Valeric acid
Not eluted
39.7
Not eluted
Columns      : Shodex RSpak DE-613 (6.0mmID*150mm)
               Shodex RSpak KC-LG (8.0mmID*50mm) + KC-811 (8.0mmID*300mm) x 2
               Shodex RSpak KC-LG (8.0mmID*50mm) + DE-613 (6.0mmID*150mm) + KC-811 (8.0mmID*300mm) x 2
Eluent       : 2mM HClO4 aq.
Column temp. : 50deg-C