What is Seeding?

Copolymer-based chromatographic resin beads are typically produced in three ways:

1. Classic batch suspension polymerization

A robust proven technology resulting in a relatively broad particle distribution that has to be adjusted by sieving.

Uniformity Coefficient: <1.6 
Typical particle size range: 100 - 1200

2. Jetting

A process where monomer phase is pushed thanks to pulse or vibration through a special steel membrane or cane into aqueous phase thus forming suspension with a narrow size distribution. A high-yield economical process, it provides products with unique performance characteristics.

Uniformity Coefficient: <1.3
Typical particle size range: 50 - 250

3. Seeding

Uniform particle size beads with a very narrow particle size distribution are created by first producing small 'seeds', which are subsequently grown (seeded) through repeated additional polymerization until the required particle size is achieved. Seeded resins are especially effective in HPLC applications

Uniformity Coefficient: <1.1
Typical particle size range: 3 - 50

Seeded polymerization: mono-size, ultra-fine beads for chromatography

Polystyrene 'seeds' are first produced through dispersion polymerization of styrene in alcohols.  These initial seeds are in the range from 1 to 5 µm.

'Seeds' can be grown in two ways depending on the physical properties required.

  • Non-porous  - typical sizes from 5 to 50 µm (swelling with monomers)
  • Macroporous - typical sizes from 5 to 30 µm (swelling with monomers and porogen)
  • Sizes currently offered: 5, 10 ,15, 20 & 30 micron
  • Narrow range of particle size, UC < 1.1 (almost monobeads)
  • Production batch: 10Kg
  • Application: Chromatography [Preparative (HPLC), processing/purification of biomolecules] and Calibration
  • Chromatography performance:
    1. Resolution (efficiency & selectivity)
    2. Loading capacity

    3. Back pressure/speed (size, porosity)
    4. Recovery

Seeding technique is used for a range of our products including Chromalite® GN (Calibration), Chromalite® AD and Chromalite® MN (Chromatography).