Frequently asked questions

Please refer also to text and downloads in other chapters of this homepage

1. What is the best method of using the MiniColumns?

2. Which resins are available in MiniColumns?

3. How are separation materials packed into MiniColumns and MiniChrom?

4. Can MiniColumns or MiniChrom units be refilled?

5. Are there prepacked columns available with rigid materials like silica or hydroxyl apatite or ceramics?

6. What are the dimensions of MiniColumns, MiniChrom and ValiChrom?

7. Which chromatography system is suitable for the operation of MiniChrom?

8. What is the backpressure of a 5-50 MiniChrom column?

9. Why is ValiChrom relatively inexpensive compared to other columns of that kind

10. What is the purpose of MaxiChrom columns

11. There is a small mark on the side of all my columns, is this a manufacturing defect?

1. What is the best method of using the MiniColumns? 

Three different functions designs are available

a) CentriColumn:
Manual or robotic pipetting of liquid (sample and eluants): Columns integrate a reservoir located on top of the resin which holds samples or eluants. Flow through the column is induced by centrifugation. (Abt. 1000 rpm, 1 min.) Results are obtained by sequential pipetting and centrifugation and plate reading.

b) PipetColumn:
Transport of liquid by a positive liquid displacement (pld) pipette, (preferable motorized). Instead of the reservoir on top of the resin, there is a patented adaptor that seals with most of the common pld-pipette tips. Positioning the tip on top of the column, holding by gentle pressure and moving the liquid by setting the slowest dispense rate. In this way all columns are operated at the same linear flow rate. Volumetric flow is accurately controlled during every pass-through the column. Eluate can be quantitatively collected ensuring accuracy between columns. Droplets coming out the column will vary according to viscosity of the mobile phase but is in the range of 25-28µl.

The StarterKit, which contains one row of 8 PipetColumns can deliver 12 different elution conditions in parallel by shifting the 8-row one position further after each elution step.

C) RoboColumn:
These columns also have the same geometry as MiniColumns and can be operated by robotic flow delivery systems. Instead of the reservoir on top of the resin, there is a needle adapter with a patented sealing system that allows you to operate the column like in a LC system.
Droplets coming out from the column have usually a volume of 28µl.

MiniColumns are NOT designed to work with vacuum for liquid transport through the resin. which can dry the column and destroy the integrity of the packed bed. In addition, the depth filters used in MiniColumns, cause no significant flow resistance. In combination with different resin flow characteristics this would potentially cause one of the 96 columns to dry out first and all the air would be sucked through that column. So in the 95 others the liquid would not move further, the same would happen using positive air pressure to move liquids.
Applying vacuum to samples containing protein can cause tremendous foaming at the lower column outlet which leads to cross contamination all over the plate.

back to the top

2. Which resins are available in MiniColumns? 

All commercially available separation materials and materials supplied by customers for individual packing that are greater then 10µm particle size. To see the continuously updated listing, please refer to our resin listing

back to the top

3. How are separation materials packed into MiniColumns and MiniChrom? 

Atoll applies flow packing to obtain a defined packing density, equivalent to large scale columns, thus results are directly transferable to production scale application.

back to the top

4. Can MiniColumns or MiniChrom units be refilled? 

No, once a prepacked column is dismantled, the housing is damaged and no re-use possible.
However the column can be regenerated as many times as the respective resin allows.

back to the top

5. Are there prepacked columns available with rigid materials like silica or hydroxyl apatite or ceramics? 

Yes, materials like silica, hydroxyl apatite or ceramics are available in both systems. The special inlet adapter in MiniChrom allows to pack all materials.

back to the top

6. What are the dimensions of MiniColumns, MiniChrom and ValiChrom? 

a) MiniColumn:
• Polypropylene columns, precision molded all are 5 mm ID.
• Max volume is 200µl (used for HIC and IEC materials)
• other volumes of 100µl or 50µl, used for high priced resins.
• ProteinA like materials are available on request.

For SEC mechanisms, in particular for Desalting the columns need to be longer in bedheight to deliver baseline or acceptable separations.
For special purpose of desalting relative large volumes in robotic handling stations , MiniChrom barrels are available, Mounted on a fitting 96array plate, equipped with a MediaScout ^® needle port to be run in fixed tip robotic stations:

Examples for such special larger units
• 24 units   5 - 50 mm
• 24 units   8 - 50 mm
• 24 units   8 - 100 mm
• 16 units   11.3 - 50 mm
• 16 units   11.3- 100 mm

b) MiniChrom:
• Polypropylene columns, precision molded
• 5 mm ID- 10 mm length = 0.2 ml
• 5 mm ID- 25 mm length = 0.5 ml
• 5 mm ID- 50 mm length = 1.0 ml


• 8 mm ID- 20 mm length = 1.0 ml
• 8 mm ID- 50 mm length = 2.5 ml
• 8 mm ID- 100 mm length = 5.0 ml


• 11.3 mm ID- 50 mm length = 5.0 ml
• 11.3 mm ID- 150 mm length = 10.0 ml

b) ValiChrom:
• Glass columns, precision bore (Schott), PMMA protection jacket.
• 11.3 mm ID- 100 - 600 mm length = 10 - 60 ml

back to the top

7. Which chromatography system is suitable for the operation of MiniChrom?

Every HPLC- or mid- or low-pressure system, capable of delivering flow rates of 0.1 ml/min and higher.
Furthermore any other liquid delivery system, e.g. a peristaltic pump or a syringe can be used with an appropriate adapter.

back to the top

8. What is the backpressure of a 5-50 MiniChrom column? 

Depending on the resin, backpressure ranges between 0.1 bar up to 10 bar.
Usually when operating 40µm resins, backpressures are 1-2bar at flow rates of 600cm/h

back to the top

9. Why is ValiChrom relatively inexpensive compared to other columns of that kind 

ValiChrom columns are constructed from precision bore glass (Schott), protection jackets from acrylic glass and end pieces machined from POM or PP, avoiding complicated and cost intensive adjustment systems. The desired length of the resin bed is precisely reached by a standard bottom adaptor and a top adaptor machined in a way to ensure the customer desired bedheigth together with a fitting glass tube length by +/- 1mm

back to the top

10. What is the purpose of MaxiChrom columns 

MaxiChrom columns are designed for use in production of biomolecules, when validation of contaminant removal is critical. Examples are production of virus probes or removal of detergents like Triton 100 with reversed phase resins after virus inactivation in bioprocessing schemes. MaxiChrom columns are usually packed with resins of >100µm particle size and have therefore relatively low back pressure values. As standard version, they consist of acrylic glass barrels and POM endpieces, sealings are Viton, frits and distribution plates are PP.

back to the top

11. There is a small mark on the side of all my columns, is this a manufacturing defect? 

The small surface imperfection which can be seen centrally on the external surface of the column barrel of MiniChrom columns is a mark created during the injection molding process. This manufacturing process guarantees the consistent and extremely high quality (ultra smooth) internal surface of many thousands of units without the need for expensive polishing. All columns are rated to a minimum of 30 Bar, and this small mark is not a sign of any structural weakness or imperfection.

back to the top