However, even when the tips of the original manufacturer are being used, traditional multichannel pipettors require a high insertion force, up to 10 kg, because of the large sealing area. This, in turn, leads to massive force needed to eject the tips, especially when using 12-channel pipettors. The tip ejection force with multichannel pipettors can vary up to threefold depending on the number of channels, tip mounting force, manufacturer, and model. Some manufacturers even recommend rocking the pipettor over the tip rack and tightening the tips by hand to ensure secure tip fitting. This is both time-consuming and causes a possible risk of contamination. Without doubt, it results in laborious tip ejection requiring much force. O-rings or elastomer tip cones eliminate that problem, but require maintenance rather often, and wear particles can contaminate samples. The mLINE Optiload system features spring-loaded tip cones (Figures 2 and 3) that allow pipettor tips to be picked up easily with a constant low force. In practice, tips cannot be sealed too tightly to the tip cones, which prevents overinsertion and jamming of the tips. This system ensures that all tips are always sealed on the same height, which is particularly important in microplate pipetting, in which it is necessary that all 12 tips reach the well bottom evenly. Thus, the springs secure optimal, even tip sealing and consistent sample loading, and reduce tip ejection force considerably, up to 65% (Figure 2). Moreover, the tip ejector design has a large, rounded surface, which makes it convenient for users and allows onehanded, low-force tip ejection. Thus, when hundreds of tip ejections are performed daily, optimal tip loading and ejection significantly reduces the risk for RSI.
Much variety exists in the volume ranges of different multichannel pipettors. For ex