Effect of Acetonitrile in Eluent (1)

Effect of acetonitrele in eluent on elution volume when RSpak KC-811 is used is shown. By adding 10% acetonitrile to the eluent, the elution time of organic acids with strong hydrophobicity can be shortened.

Substance Elution Volume (mL)
3mM HClO4 aq./CH3CN
=90/10
3mM HClO4 aq.
Oxalic acid
9.28
9.62
Maleic acid
9.91
10.51
alpha-Ketoglutaric acid
10.39
10.87
Citric acid
10.99
11.71
Isocitric acid
11.05
11.88
2-Ketogluconic acid
11.18
11.52
Glucuronic acid
11.29
11.71
Oxalacetic acid
11.40
11.77
Pyruvic acid
11.42
11.76
Phosphoric acid
11.43
11.27
Tartaric acid
11.53
12.14
trans-Aconitic acid
11.57
13.11
Galacturonic acid
11.90
12.41
Malonic acid
12.10
12.96
Gluconic acid
12.24
12.78
Malic acid
12.37
13.37
Glyoxylic acid
12.70
13.26
alpha-Hydroxygltaric acid
12.71
14.02
Ascorbic acid
12.71
13.88
Succinic acid
13.77
15.79
Itaconic acid
14.08
16.80
Fumaric acid
14.14
17.16
Uric acid
14.99
18.31
Glycolic acid
15.12
16.26
Adipic acid
15.16
20.17
Lactic acid
15.23
16.67
2-Hydroxyisobutyric acid
15.26
17.05
Mesaconic acid
15.42
20.47
beta-Hydroxypropionic acid
15.61
17.18
Levulinic acid
16.44
20.27
Formic acid
16.59
17.86
Acetic acid
17.32
19.41
Pyroglutamic acid
18.02
20.99
Propionic acid
18.82
22.54
Isobutyric acid
20.13
25.59
n-Butyric acid
20.87
27.61
Isovaleric acid
22.16
32.28
CO32-,HCO3-
23.36
24.50
n-Valeric acid
24.64
38.89
Columns      : Shodex RSpak KC-811 (8.0mmID*300mm) x 2
Eluent       : 3mM HClO4 aq./CH3CN=90/10, 3mM HClO4 aq.
Flow rate    : 1.0mL/min
Column temp. : 50deg-C