At present, there are two main pipette technologies to meet the precise liquid transfer needs of different liquids:

1. Built-in piston pipetting mode: suitable for conventional pipetting operation. The piston is located in the pipette sleeve, and there is an air isolation between the liquid and the piston, and the piston is not in contact with the liquid. This is a very common pipette in the lab. When using, be careful not to let the sample contaminate the piston, otherwise it will cause sample cross-contamination.

2. External piston pipetting mode: suitable for operation of high viscosity liquid. The piston is located outside the pipette sleeve and inside the suction nozzle. There is no air between the piston and the liquid. Pistons are disposable. It also enables accurate liquid delivery for liquids with high viscosity. Since there is no air interval, possible aerosol cross-contamination caused by sample contact with air is avoided. Therefore, it is also very suitable for the transfer of valuable reagents and biological samples.

3. Straw suction head Product requirements: As a disposable consumable, the straw suction head can be in direct contact with the liquid sample, which will not only affect the accuracy of the straw results, but also directly affect the analysis results if the straw suction head dissolves and contains foreign biological pollutants.

The suction head is generally made of pure PP material, without plasticizer and release agent, otherwise the dissolved matter will affect the experimental results; High dimensional accuracy is required, otherwise it will lead to poor sealing consistency; The inner wall is smooth without flow marks, and the tip has no notch or burr, otherwise the drainage is not accurate; It is clean and free of biological contamination. It needs to be manufactured in an ultra-clean environment.

While most standard pipette heads do not require electrical conductivity, the pipette heads used for liquid handling in drug detection systems require not only electrical conductivity, but also excellent physical properties and chemical resistance. In addition, as pipette head designs become longer and larger, the conductive compounds used to make the heads need to become easier to flow to accommodate a narrower processing window.