akzonobel logo

Kromasil Eternity - Benefits

Long-lasting columns

We have performed long term stability tests under harsh pH conditions that show that Kromasil Eternity performs very well.

Plate count evolution relative to initial value

Amitriptyline
evolution of efficiency in amitriptyline test over time
Prednisolone
evolution of efficiency in prednisolone test over time
Test conditions
Columns: Kromasil Eternity-5-C18 4.6 × 250 mm
Waters XBridge, 5 μm, C18, 4.6 × 250 mm
Mobile phase A: 10 mM ammonium bicarbonate, pH 10.5/acetonitrile (90/10)
Mobile phase B: 10 mM ammonium bicarbonate, pH 10.5/acetonitrile (10/90)
Flow rate: 1 ml/min
Temperature: 45°C
Gradient: 0 min 100% A, 0 min 100% B, 15 min 100% B, 16 min 100% A, 20 min 100% A
Test amitriptyline: 10 mM ammonium bicarbonate pH 10.5/acetonitrile (30/70)
Test prednisolone: 10 mM ammonium bicarbonate pH 10.5/acetonitrile (70/30)
Test cycle: 6 × gradient + test = 172 min/cycle

« Previous | Next »

Control selectivity

retention time may differ for substances a different pH

Be free to choose the pH that will give you the best selectivity and optimal runtime for your application.

Test conditions
Columns: Kromasil Eternity-2.5-C18 4.6 × 50 mm
Mobile Phases: acetonitrile/20 mM sodium phosphate
pH 2.1, 7.2 and 11.0, respectively
Gradient: 0-0.5 min: 10%, 5.5 min: 50% acetonitrile
Flow rate: 1.5 ml/min
Temperature: 25°C
Detection: UV 254 nm


retention time may differ for substances a different pH

« Previous | Next »

Time efficiency

Smaller particles give higher plates count per meter. A shorter column with smaller particles can do the same work as a longer one with larger particles. Time and eluent consumption can be minimized.

run at 1/14 ot the original analysis

run at 1/14 ot the original analysis
Phase: Kromasil Eternity-5-C18 Phase: Kromasil Eternity-2.5-C18 Phase: Kromasil Eternity-2.5-C18
column size: 4.6 × 250 mm column size: 4.6 × 100 mm column size: 4.6 × 50 mm
Flow rate: 1.0 ml/min Flow rate: 1.6 ml/min Flow rate: 2.7 ml/min


Test conditions
Mobile Phase: acetonitrile/water/formic acid (25/75/0.1)
Temperature: 25°C
Detection: UV 254 nm
Substances: Mix of sulfa drugs, 1 = uracil,
2 = sulphathiazole,
3 = sulphamerazin,
4 = sulphamethoxazole

« Previous | Next »

Scale up – scale down

Scale up your analytical application developed on small particles to a column with larger particles. Scale down your semi-prep purification step to a smaller column for efficient optimization. Retention times are maintained either way.

3 chromatograms at different dp and i.d. - same retention times
Test conditions
Mobile Phase: acetonitrile/50 mM triethylamine acetate, pH 11 (40/60)
Flow rate: 0.43 ml/min and 9.0 ml/min for 4.6 and 21.2 mm i.d. columns, respectively
Temperature: 20°C
Detection: UV 230 nm
Sample: Mix of β-blockers, 1 = uracil,
2 = atenolol, 3 = pindolol,
4 = metoprolol, 5 = propanolol,
6 = alprenolol

« Previous | Next »

« Previous | Next »

· Eka Chemicals, Separation Products · SE–445 80 Bohus, Sweden · Phone +46 31 58 70 00 · Fax +46 31 58 77 27 ·
· E-mail kromasil@akzonobel.com ·