What are the factors that affect the selection of pipette tips

Texture of material:
Nowadays, the suckers on the market are basically made of polypropylene plastics (colorless transparent plastics with high chemical inertness and wide temperature range).However, as with polypropylene, quality varies widely: high-quality suckers are generally made of natural polypropylene, whereas low-cost suckers are likely made of recycled polypropylene plastics (in this case, we can say that the main ingredient is polypropylene at best).In addition, a small amount of additives will be added to most of the suckers in the manufacturing process. Common ones are: 1. Color developing materials.Commonly known in the market as blue gunhead (1000ul) and yellow gunhead (200ul), is the addition of corresponding color-developing materials in polypropylene (we hope to be a high-quality color master batch, rather than a low-cost industrial pigment); 2, demoulding agent.Help the sucker to detach from the mold quickly after forming.Of course, the more additives, the higher the probability of undesirable chemical reactions occurring during pipetting.So it's best not to add additives!However, due to the relatively high production process requirements, absolutely no additives are rare in the market.

Packing:
The packaging form of suction head mainly includes bag and box.In the relatively mature market, boxes dominate; in China, bagging is currently the absolute mainstream - mainly or inexpensive.The so-called bagging is to put the suction head in a plastic self-sealing bag, 500 or 1000 per bag (the number of suction head per bag in a large range will be much less).Most users buy bagged suckers and manually place them in the sucker box.Although China's labor force is cheaper, it also increases the chances of contaminating the suction head!In addition, in recent years, a new packaging form has emerged, that is, supplementary packaging (8 or 10 plates of suction head stacked into a tower, can quickly put the suction head into the suction box without touching the suction head).This suction head requires less storage space and substantially reduces the use of plastics to achieve environmental protection.Although the share of this form in China is still very small, it must be the trend of the times in the long run.

Special suction tip:
The so-called special suction head is a suction head specially designed for special samples or special applications.There are mainly the following categories: 1. Gel tip (spot tip).The tip of the suction head is flat or very thin, which is mainly used in electrophoresis experiments; second, wide mouth suction head.The diameter of the tip of the suction head is larger than usual, and it is mainly used to remove macromolecular solutions such as proteins. Third, the low-adsorption suction head.The inner wall of the suction head is specially treated, which reduces the surface adsorption force and is used to remove viscous liquid. Fourth, lengthen the suction head.Used for liquid extraction in containers such as volumetric flasks; 5. External piston suction head.Mainly used on special pipettes, such as external piston pipettes and continuous distributors.

Adaptability:
Not all suckers can be used on any brand of pipette of the corresponding range, so we have to remind the user of the suitability of the sucker.To this end, we can interpret the problem of suitability from the following aspects: First, the specificity of the suction head.Some brands of pipettes can only use their own suckers, others can not use at all.For example, RAININ multichannel pipettes must use RAININ's LTS tip; second, the degree of adaptation.Most often, a pipette can use a variety of tips, but the effect of pipetting varies.For example, EPPENDORF's multichannel pipettes use EPPENDORF's suction head, which is a first-class rod for both sensation and accuracy of pipetting, but EPPENDORF's multichannel pipettes use Axygen's suction head is unsatisfactory; and third, the adjustment of the measuring range.Generally speaking, the maximum range of a pipette is less than or equal to the volume of the suction head. For a pipette with a maximum range of 1000 ul, the suction head with a maximum range of 200 UL can be adapted to a pipette with a maximum range of 20 ul, 100 UL and 200 ul. Fourth, the specificity of the suction head for a large-range pipette (5 ml, 10 ml and 20 ml).Various brands of large-range pipettes often need their own suction tips, making it difficult to find alternatives.So, if you need to buy a suction tip, it is recommended that you tell the supplier the type of suction tip you are using or at least provide the brand and range of the pipette you are using.

Biological contamination:
Nowadays, more and more users will require the suction tip to be free of RNAase, DNase, DNA, pyrogen and ATP contamination.This is a good phenomenon, but I have to remind two points: high temperature sterilized suction head does not guarantee no biological contamination, to ensure no biological contamination requires gamma ray treatment and other steps.Therefore, it is almost impossible for the user to treat the ordinary suction head as a non-bio-contaminated suction head, and the box suction head purchased without bio-contamination should provide the corresponding certificate, indicating the detection data of the corresponding items.It is better not to believe that there is no data on the certificate or even no certificate tip;
Second, some brands of bagged suction tips will have a label declaring no biological contamination, which is quite speculative and even deceptive suspicion.Imagine: As long as the suction head touches the air, there will be biological pollution, and ordinary self-sealing bags can ensure that the suction head does not touch the air at all during storage and transportation?In addition, self-sealing bags are punctured by suction head from time to time.

Filter tip:
As the name implies, there is a usually white filter element at the top of the suction head.Most of the filter elements are made of polypropylene, similar to the filter nozzle structure of cigarettes.Due to the presence of filter element, the sample removed cannot enter the interior of the pipette, thus protecting the parts of the pipette from pollution or even corrosion, and more importantly, ensuring that there is no cross-contamination between samples.Therefore, the filter tip is also an important tool to remove volatile and corrosive samples.Of course, the price of filter element suction head is relatively high and its market share in China is very low.In addition, there are few domestic filter-element suckers, and their filtration effect is also unsatisfactory.