FAQs - Frequently asked questions

Below, to assist you we have collated the most usefull frequently asked questions (FAQs).

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Pipette tips

When should a filter tip be used?

If contamination of the samples and the pipettes through aerosols (e.g. acids), biomolecules (e.g. RNA or DNA) or accidental over-pipetting needs to be avoided. This is particularly important in the case of critical applications such as PCR reactions. 

The economical Tip StackPack refill system is made up of fed-in 96-tip trays which are stacked in one another and can simply be transferred into a Tip SystemBox for use. This reduces the amount of packaging and waste and the storage space required by more than 50%.

It is not necessary to autoclave our tips. Filter tips should not be autoclaved as the filter structure can change, which means the functionality of the filter is no longer ensured. 

 The improved processing properties of the low retention pipette tips mean that a smaller residual volume remains in the syringe, so a more even and more complete transfer of liquid can be achieved. This is important in particular when handling small amounts of nucleic acid (e.g. in the case of PCR and qPCR) when the focus is on the precision of the sample transfer and the reproducibility of the results.

Tubes

When should a low retention pipette tip be used?

 The improved processing properties of the low retention pipette tips mean that a smaller residual volume remains in the syringe, so a more even and more complete transfer of liquid can be achieved. This is important in particular when handling small amounts of nucleic acid (e.g. in the case of PCR and qPCR) when the focus is on the precision of the sample transfer and the reproducibility of the results.

The use of PP tubes at temperatures below zero centigrade must be carefully tested under real conditions as the load on the tubes can be very different depending on the medium to be frozen and the routine conditions. We are able to give you some tips on the basis of our experience and tests we have carried out on PP tubes. In principle, with products made of PP, the strength values are reduced at temperatures below 0°C, and it is therefore necessary to ensure that the frozen tubes are not exposed to any particular mechanical loads (e.g. do not let the tubes fall off the table). The freezing conditions must be selected such that the content can be evenly frozen or frozen from the bottom to the top. Cracks caused by strain can occur in the lower part if the upper part of the tube freezes first as a result of unfavourable freezing conditions. For example, depending on the diameter of the hole, stands made out of Styrofoam have a strongly insulating effect which makes it more difficult to ensure the even freezing of the tubes. In principle, the tubes should have sufficient room to expand in a stand or storage container. Due to the large number of possible influence factors, we recommend you carry out a freezing test under your routine conditions.

Products or product components manufactured from polyethylene (PE) cannot in principle be recommended forautoclaving at 121'C. This is due to the low temperature resistance of the PE plastic, which has a maximum long.term use temperature of 60-80'c. it is therefore not possible to rule out an impairment of the product. One exampleof such an impairment is geometric distortion, which can lead to leaks in tubes.

If reagent and centrifuge tubes are manufactured from polypropylene or polycarbonate, they can be autoclaved at 121°C without any appreciable loss of mechanical properties. Due to their low temperature resistance, tube caps typically manufactured from polyethylene (PE) cannot be recommended for sterilisation by autoclaving. Screw caps made from polypropylene (PP) should be slightly loosened to prevent tube deformation caused by pressure and temperature changes during the autoclaving process. The user must check whether other product characteristics are affected by autoclaving in terms of the desired use.

The different types of tubes and materials used do not allow to make a general statement on this. You can find a more accurate statement on centrifugability in the product specifications for the respective item.

If contamination of the samples and the pipettes through aerosols (e.g. acids), biomolecules (e.g. RNA or DNA) or accidental over-pipetting needs to be avoided. This is particularly important in the case of critical applications such as PCR reactions.