First, extra suction heads.
Special tips are specially designed tips for special samples or special applications. There are mainly the following categories: the first category is gel tips (also known as spotting tips): the tips of the tips are either flat or very thin, and are mainly used for electrophoresis experiments; the second category is wide-mouth tips: suction tips The diameter of the tip of the tip is larger than that of general tips, and it is mainly used to remove macromolecular solutions such as proteins; the third type is low-adsorption tips: the inner wall of these tips has been specially treated to reduce the surface adsorption force and can be used to remove viscous Liquid; the fourth category is the extension tip: mainly used for liquid extraction in containers such as volumetric flasks; the fifth category is the external piston tip: mainly used for external piston pipettes and continuous dispensers and other special on the pipette.
Second, the adaptability of pipette tips.
The adaptability of pipette tips is a point that users are paying more and more attention to. Why? Because not all tips can be used on pipettes of any brand and corresponding range, Leibe reminds us again that users must pay attention to the adaptability of tips when purchasing tips. First of all, we can understand the adaptability of the tip from the following aspects: First, the specificity of the tip. Some series of pipettes of some brands can only use their own standard tips, and other tips cannot be used. For example, Rainin's multichannel pipette must use its own LTS tips; second, the degree of tip adaptation. The most common situation is that a pipette can use multiple tips, but the effect of pipetting varies with different tips. In general, the standard tips are still the best, but some brands of tips are still good, such as Axygen tips. Third, the range of the tip and the pipette should be adapted. In general, the volume of the tip should be greater than or equal to the maximum range of the pipette. For example, a 200ul tip can be used for pipettes with a maximum range of 20ul, 100ul and 200ul; 10ml and 20ml) tip specificity. Large-scale pipettes of major pipette brands generally require their standard tips, and it is difficult to find alternatives. Therefore, if we need to purchase tips, it is recommended to tell the supplier the type of tips we apply or at least the brand and volume of pipettes we use.
Third, biological pollution.
Now, an increasing number of users are pleading for tips that are RNase-free, DNase-free, DNA-free, pyrogen-free and ATP-free. This is a good scene, but Leibe has to remind two more points: First, high-temperature sterilized tips cannot completely guarantee no biological contamination. To ensure no biological contamination, processes such as gamma ray treatment are required. Therefore, it is almost impossible for users to process ordinary tips into non-biological contamination tips, and the purchased non-biological pollution-free boxed tips should be provided with corresponding certificates, indicating the viewing data of the corresponding items. There is no data on the certificate or even the tips without the certificate can not be proved to be completely pollution-free; secondly, the bagged tips cannot guarantee no biological pollution. As long as the suction tip comes into contact with the air, it may be contaminated by organisms, and generally, the ziplock bag cannot guarantee that the tip will not touch the air during storage and transportation; in addition, the ziplock bag is sometimes punctured by the suction tip. has happened. Therefore, if you have high requirements for the tip, you must check with the supplier when you purchase it to understand whether the tip has a certificate indicating the viewing data of the corresponding item.
Fourth, the suction head with filter element.
A filter tip has a filter (usually white) on the top of the tip. This filter element is typically made of polypropylene, similar to the construction of a cigarette filter. Because of the existence of this filter element, the pipetted sample cannot enter the inside of the pipette, and then it protects the parts of the pipette from contamination and corrosion. More importantly, it can also ensure that there will be no cross-contamination between samples. Therefore, filter tips are also a primary tool for pipetting volatile and corrosive samples. Of course, the price of filter tips is higher than that of general tips, and the domestic market share is very low. Moreover, there are very few domestically produced suction heads with filter elements, and its filtering effect is also unsatisfactory.