The performance and accuracy of any pipette can be seriously affected by the use of poor quality or unsuitable suction heads. As a system, the pipette and pipette suction can only be matched to ensure the accurate transfer and delivery of liquid. After mastering the correct pipetting technology and matching the recommended suction head, the pipetting accuracy can be guaranteed.
It is generally divided into: ① bagged suction head ② boxed suction head ③ low adsorption suction head ④ filter element suction head ⑤ automatic suction head.
At present, the suction heads on the market are basically made of polypropylene plastics (colorless transparent plastics with high chemical inertness and a wide temperature range). However, the same polypropylene, the quality difference will be very large: high-quality suction heads are generally made of natural polypropylene, while cheap suction heads are likely to be recycled polypropylene plastic (in this case, it can be said that the main component is polypropylene).
In addition, most suction heads in the manufacturing process will also add a small number of additives, common are:
1. Color developing materials. In the market, commonly known as the blue gun head (1000ul) and the yellow gun head (200ul), is to add the corresponding color developing material (high-quality color masterbatch, rather than cheap industrial pigments) in polypropylene;
2. Release agent. Helps the suction head quickly detach from the mold after forming. Of course, the more additives, the higher the probability of unwanted chemical reactions occurring during the pipetting process.
The filter element suction is used to avoid cross-contamination of the pipette process or contamination of the pipette by aerosol particles generated during the pipette process without any difference in the performance of the pipette. Filter cartridge suction heads are recommended to prevent DNA or RNA contamination (genomic applications, PCR) or to remove volatile solutions to prevent potentially corrosive vapors from entering the pipette and damaging the piston.
The low adsorption suction has two main advantages over the standard polypropylene suction. First, regardless of the composition or physical properties of the liquid, they help to maximize the discharge of the sample liquid from the suction head. This means that the distribution of viscous liquids and other stubborn liquids, such as liquids with reduced surface tension, will be optimized.
Second, for laboratories that frequently remove a range of different sample liquids, the low-residue surface "standardizes" the movement of liquids in and out of the suction head. This means that the pipetting accuracy of liquids with different compositions and physical properties is adjusted to maintain greater uniformity when a variety of different liquids with different physical properties are routinely used in a specific laboratory environment.
The extended suction head is much longer and slightly narrower than the standard suction head. These are designed to provide additional "stretch range" when aspirating fluid and are recommended for extracting samples from certain tall and narrow containers, such as tubes and vials, that cannot be reached by the tip of a standard length.
The main packaging forms of the suction head are bags and boxes. In more mature markets, boxed sets dominate; In China, bags are now the absolute mainstream - mainly cheap bags. The so-called bag is to put the suction head in a plastic ziplock bag, each bag 500 or 1000 (the number of large range suction head per bag will be much less).
Most users will buy a bag of suction head, and then manually put the suction head into the suction box. Although China's labor is relatively cheap, but this also increases the chance of pollution suction! In addition, in recent years, there has been a new form of packaging, that is, supplementary packaging (8 or 10 plate suction heads stacked into a tower, you can quickly put the suction head into the suction box without touching the suction head).
The suction requires less storage space and significantly reduces the use of plastic, thus achieving the purpose of environmental protection. Although this form of domestic share is still very small, but in the long run must be the trend of The Times.
Compared with the standard pipette head, the automatic pipette head is mainly adapted to the pipette workstation and the automatic sampling system for high-throughput pipette experiment. It can be used in genomics, proteomics, cytoomics, immunoassay, metabolomics, biopharmaceutical research and development, and other commonly used high-throughput pipette needs.
The automatic pipette workstation is a fully automated operation, and the suction head moves in the whole form to remove the same volume, which greatly reduces the labor cost, reduces human error, enables the experimentor to get rid of complex experimental operations, has higher efficiency, realizes standardization, and improves data security and traceability.