The working principle of serological pipettes is based on piston-driven air displacement technology. When the piston moves upward, negative pressure is formed inside the pipette, and the external liquid is sucked into the pipette tip; when the piston moves downward, the liquid is discharged. This process seems simple, but it actually involves complex mechanical and fluid mechanics principles.

To ensure operating accuracy, modern serological pipettes are usually equipped with precise mechanical structures and electronic control systems. In terms of mechanical structure, the matching clearance between the piston and the sleeve, the material and shape design of the pipette tip are strictly calculated and tested to reduce liquid residue and bubble generation. The electronic control system monitors the piston position and liquid volume in real time through sensors to achieve closed-loop control and further improve accuracy.

The impact of operating specifications on accuracy and stability
When aspirating liquid, the thumb should be released slowly and steadily to avoid the liquid being sucked in too quickly and rushing into the pipette to corrode the plunger. When discharging liquid, the mouth of the pipette tip should be attached to the bottom of the inner wall of the container and maintained at a certain tilt angle. The button should be pressed steadily to the stop point, and then pressed to the second stop point after waiting for one second to discharge the remaining liquid. These operating details can effectively reduce liquid residue and bubble generation, and improve accuracy.

For viscous or volatile liquids, tip pre-wetting and reverse pipetting are effective means to improve accuracy. Tip pre-wetting moistens the inner wall of the tip by repeatedly sucking and pumping the liquid several times to reduce liquid residue. The reverse pipetting method presses the second gear when sucking liquid, slowly releases the control button, and presses the second gear when pumping liquid. Some liquid remains in the tip, thereby reducing the error when discharging liquid.

Choosing the right range is crucial to improving accuracy. Do not use a large-range pipette to transfer a small volume of liquid to avoid affecting accuracy. When setting the range, make sure that the numbers are clearly displayed in the display window to avoid turning the button out of the range, which may cause the mechanical device to get stuck or damaged.

The impact of environmental factors on accuracy and stability
Changes in temperature and humidity will affect the volume and density of the liquid, thereby affecting the accuracy of pipetting. The laboratory should maintain a constant temperature and humidity environment, especially when conducting high-precision experiments. For temperature-sensitive liquids, such as serum, it is recommended to balance at room temperature (15℃-25℃) before pipetting.

Vibration and electromagnetic interference will interfere with the electronic control system of the pipette, resulting in reduced accuracy. Laboratories should avoid using pipettes in strong vibration or strong electromagnetic field environments. If you need to operate in an environment with large vibrations, consider using an anti-vibration table or shock-absorbing pad.

The cleanliness and sterility of the pipette have an important impact on the experimental results. Before use, check whether the pipette mouth and tip are intact to ensure that there is no damage or deformation. After use, the pipette should be cleaned in time to remove residues and avoid cross contamination. For experiments with high requirements for aseptic operation, disposable sterile pipette tips should be used.

The impact of maintenance on accuracy and stability
The accuracy of the pipette will decrease due to wear, aging and other reasons during use. Regular calibration is an important means to ensure the accuracy of the pipette. It is recommended to calibrate once every 3-6 months, or adjust the calibration cycle appropriately according to the frequency of use and experimental requirements. Calibration can be performed by weighing the weight of the pure water taken on an analytical balance and calculating it.

Pipette cleaning and disinfection are key to maintaining its stability. After use, the pipette should be cleaned in time to remove residues. For pipettes that need to be disinfected, 75% ethanol or other suitable disinfectants can be used for wiping or soaking disinfection. Be careful to avoid disinfectants entering the interior of the pipette and damaging electronic components.

Pipette consumable parts such as pistons and sealing rings need to be replaced regularly to ensure their sealing and operability. It is recommended to replace them according to the manufacturer's recommended cycle, or adjust them according to actual usage. When replacing consumable parts, original accessories or certified compatible accessories must be used to avoid using inferior accessories that may cause pipette performance degradation.

Pipette should be stored in a dry, ventilated, dust-free environment when not in use, avoiding direct sunlight and high temperature. When stored for a long time, the pipette can be hung on a pipette rack to avoid flat placement, resulting in residual liquid in the tip corroding the inside of the pipette. Regular maintenance of the pipette, such as lubricating the piston and checking the sealing, can extend its service life and improve stability.