How to disinfect and sterilize a pipette

Although the pipette is small, as one of the routine laboratory instruments, it still plays a significant role in the accuracy and reliability of our experimental results. Therefore, in order to improve our experimental effectiveness, this article will discuss the disinfection and sterilization treatment of the pipette. For pipettes, the concepts of disinfection and sterilization are often confused. In fact, there is a certain difference between the two: disinfection only requires controlling the live bacteria on the pipette within a certain range, reaching a harmless level; Sterilization is even stricter, requiring the elimination of all live bacteria. Therefore, the requirements for sterilization are higher than those for disinfection.

1、 Pipette disinfection

There are two methods for disinfecting pipettes:

1. Chemical disinfection. Simply put, it is to wipe the outer surface of the pipette with alcohol or other substances, and then air dry it. This should be achievable for all pipette brands; If there is a certain type of pipette that cannot be disinfected using chemical methods, it can only prove that the material of its casing is very poor.

2. UV disinfection. It is to irradiate the surface of the pipette with ultraviolet light to achieve disinfection by destroying the DNA structure of cells. The duration of ultraviolet disinfection depends on the radiation intensity and the strength of bacteria's resistance to ultraviolet radiation. Most brands of pipettes can be disinfected with ultraviolet light, but it is still necessary to confirm with the supplier in advance, as not all pipettes can be disinfected with ultraviolet light.

2、 Sterilization of pipette

Firstly, let's talk about conventional high-temperature and high-pressure sterilization treatment

1. If it is a pipette that cannot be sterilized as a whole, first package the parts that need to be sterilized with sterilization bags, tin foil, or kraft paper, at 121 ℃, 1 bar atmospheric pressure, for 20 minutes; After sterilization, let it dry at room temperature, apply oil to the piston, and then proceed with assembly.

2. If it is a fully disinfectable pipette (such as the German IKA pipette), the entire pipette can be placed at 121 ℃ and 1 bar atmospheric pressure for 20 minutes of high-temperature and high-pressure disinfection.

3. If some pipettes cannot be sterilized under high temperature and pressure, but need to be used for certain special operations such as RNA extraction, and there is concern that the pipette may be contaminated and affect the experimental results, then clean the pipette head with 75% ethanol.

If used for RNA extraction, 75% ethanol without RNase contamination should be used.

Attention: Half disinfected pipettes should not be used for whole tube disinfection, otherwise there may be obvious phenomena such as discoloration of the reading digits and inaccurate readings.

Next is UV irradiation sterilization

The pipette is made of high-quality materials that are resistant to ultraviolet radiation, and the entire pipette can be exposed to ultraviolet radiation for surface disinfection.

3、 Removal of DNA contamination on pipettes

Let's first talk about the handling method:

1. Dilute the 10X storage solution to 1 times the buffer solution, and soak the inner and outer sleeves of the removed lower part of the pipette at 95 ℃ for 30 minutes.

2. Rinse the sleeve clean with distilled water.

3. Dry at 60 ℃ or air dry.

4. Apply silicone oil to the surface of the piston and assemble the components.