Effect of Concentration of Eluent on Elution Volume

As the pH of the eluent and the column temperature affect the dissociation of organic acids, they are important for the adjustment of separation when RSpak KC-811 is used.

Substance Elution Volume (mL)
1mM
HClO4		 2mM
HClO4		 3mM
HClO4		 5mM
HClO4
Oxalic acid
9.27
9.41
9.62
9.72
Maleic acid
9.70
10.15
10.51
11.12
alpha-Ketoglutaric acid
9.96
10.44
10.87
11.37
Oxalacetic acid
10.48
11.22
11.77
12.50
Pyruvic acid
10.51
11.24
11.76
12.48
2-Ketogluconic acid
10.59
11.13
11.52
11.73
Phosphoric acid
10.61
10.95
11.27
11.58
Citric acid
10.84
11.32
11.71
11.81
Tartaric acid
11.06
11.66
12.14
12.31
Isocitric acid
11.10
11.54
11.88
11.89
Glucuronic acid
11.16
11.44
11.71
11.76
trans-Aconitic acid
11.47
12.43
13.11
13.48
Malonic acid
11.54
12.36
12.96
13.40
Galacturonic acid
11.83
12.12
12.41
12.39
Gluconic acid
12.29
12.53
12.78
12.48
Glyoxylic acid
12.35
12.86
13.26
13.86
Malic acid
12.50
12.99
13.37
13.42
alpha-Hydroxygltaric acid
13.47
13.91
14.02
14.15
Ascorbic acid
13.53
13.69
13.88
13.80
Fumaric acid
14.47
16.09
17.16
17.75
Succinic acid
15.30
15.52
15.79
15.69
Glycolic acid
15.60
15.92
16.26
16.22
Itaconic acid
15.92
16.42
16.80
16.79
Lactic acid
16.02
16.39
16.67
16.68
2-Hydroxyisobutyric acid
16.52
16.82
17.05
17.05
Adipic acid
16.65
19.84
20.17
20.01
beta-Hydroxypropionic acid
16.94
17.04
17.18
17.12
Formic acid
17.18
17.55
17.86
17.92
Mesaconic acid
17.20
19.20
20.47
21.06
Uric acid
17.89
17.93
18.31
18.00
Pyroglutamic acid
18.59
20.25
20.99
21.65
Acetic acid
19.19
19.29
19.41
19.36
Levulinic acid
20.01
20.19
20.27
20.23
Propionic acid
22.33
22.43
22.54
22.49
CO32-,HCO3-
24.72
24.72
24.50
24.68
Isobutyric acid
25.35
25.47
25.59
25.55
n-Butyric acid
27.32
27.46
27.61
27.57
Isovaleric acid
31.89
32.07
32.28
32.20
n-Valeric acid
38.36
38.57
38.89
38.75
 
Columns      : Shodex RSpak KC-811 (8.0mmID*300mm) x 2
Eluent       : HClO4 aq.
Flow rate    : 1.0mL/min
Column temp. : 50deg-C