by Dr Nicolas Gerst
Pipettes are important tools widely used in the lab. They are usually chosen and purchased carefully with the goal of receiving the best performance for a given price. Pipette tips are consumables; therefore, price can be an important factor, sometimes at the detriment of quality and performance. We found that tips from pipette manufacturers performed as expected but certain third-party manufacturer products performed just as well.
Have you ever wondered if you are using the correct tip for your pipette? There are several articles warning users that inaccurate pipetting is often caused by using the incorrect tip [1, 2]. Most pipette manufacturers sell pipette tips so the choice should be easy, right? Well, that may not always be the case. To be on the safe side you just automatically buy the same brand tips as the brand of your pipette, not even taking into consideration third-party manufactured options. However, you should not make your buying process this straight forward.
Many laboratories use multiple brands of pipettes. Pricing is often a driving factor for using various options, with the goal of researchers and lab managers being to purchase a tip that works well for all pipettes at a reasonable price. In this article we will explore the results of an experiment we conducted comparing pipette manufacturer tips versus third-party tips.
One tip for all pipette brands
Lab managers and researchers question whether they can use one type of tip for all their different pipettes. Our experiment tested tips from pipette manufacturers and third-party manufacturers on three different pipette brands (Gilson, Sartorius and ThermoFisher). The pipettes used in this study are manual single channel pipettes. With every user the random error may be affected by the user’s pipetting technics. Muriel Art et al. use an electronic pipette for their test bringing more consistency between each pipetting . Manual pipettes are widely used by researchers; therefore, it is important to test these too .
Material and methods
We used three pipettes from the following different original manufacturers (Gilson, Sartorius and ThermoFisher Scientific).
- Finnpipette™ 200 μl (ThermoFisher Scientific; serial no. CH38384)
- BioHit mLine® m200 (Sartorius; serial no. 7518885)
- PIPETMAN® Classic P100 (Gilson; serial no. L14257L)
The performance of the combination of pipette and tip was determined using the gravimetric method with a Practum® 224-1S analytical balance (Sartorius). We set up the experiment in a room free of draft with a relative humidity above 45% and a constant temperature (between 15 °C and 25 °C). Humidity, temperature and atmospheric pressure were measured during each experiment to calculate the Z factor, which is used in the calculation of water volume and needed for pipette calibration. The measurements (ten) were performed at 10% and 100% nominal volumes with or without a tip change.
We calculated the systematic error and the random error according to the formula found in the manual of the pipettes. Also, the formula is the same for all the pipettes, the error limits are different and will be used in the graph later on (red line).
Details of the different tips used in this study are shown in Table 1, and they were all bought in bulk.
Regarding packaging, tips A, B and C came in a box that was well labelled (size, plastic type, expiration date). Tips D and E came in a bag, also well labelled. Tips F and G came in a bag with a small sticker with a number (maybe a lot number). All the tips are clear except for tip G, which has a yellow colour.