Digital pipettes are the core tool for precise pipetting in laboratories, but improper operation can easily lead to data deviation or equipment damage. Mastering the following key steps and techniques can significantly improve experimental efficiency and accuracy.

1、 Standardized operating procedures

Range adjustment

Rotate the adjustment knob to the target volume and observe the display screen to confirm that the value is stable. Avoid rapid rotation to prevent internal gear wear (such as when moving 200 μ L, slowly adjust to align with the scale line).

Suction head installation

Gently press the suction head vertically until it makes a "click" sound to ensure sealing. Do not insert or strike diagonally, otherwise it may cause leakage (experiments have shown that incorrect installation may result in a loss of 5% -10% of volume).

Pre rinse suction head

Before suctioning, rinse 2-3 times with the target liquid to reduce the impact of surface tension. High viscosity liquids (such as glycerol) must be rinsed, otherwise the volume deviation may exceed 15%.

Liquid absorption and discharge

Liquid suction: Dip the suction head 2-3mm below the liquid surface, slowly release the button to the first gear, and hold for 1-2 seconds to allow the liquid to fully enter.

Drain: Press the container wall tightly and slowly to the second gear. A small amount of liquid (<10 μ L) needs to be in contact with the container wall for more than 3 seconds to drain the residual liquid.

2、 Key operational skills

Angle control: Keep the pipette vertical (tilt<15 °), avoid the suction head from contacting the bottom or side wall of the container, and prevent bubbles or splashing.

Temperature matching: If there is a large temperature difference between the liquid and the suction head (such as a sample taken from 4 ℃), it is necessary to let it stand at room temperature before transferring the liquid to reduce thermal expansion and contraction errors.

Speed adaptation: Low viscosity liquids (such as water) can be operated quickly, while high viscosity liquids (such as serum) need to be slowed down to reduce wall adhesion.

3、 Common misconceptions and corrections

Misconception 1: Immediately drain the liquid after absorbing it

Problem: The liquid is not fully filled in the suction head, resulting in insufficient volume.

Correction: After suctioning, stay for 1-2 seconds, especially for trace or high viscosity liquids.

Misconception 2: Mixing liquids with a pipette

Problem: Repeated blowing and hitting can introduce bubbles or change concentration, and even damage the piston.

Correction: When mixing, use an oscillator or mix it upside down.

Misconception 3: Long term fixed range without calibration

Problem: Frequent use of the same measuring range (such as 100 μ L) can accelerate gear wear and reduce accuracy.

Correction: Regularly rotate the measurement range and calibrate according to ISO8655 standard every 6 months.

Misconception 4: Direct use after high-temperature sterilization

Problem: Residual water vapor on the suction head affects accuracy.

Correction: After sterilization, air dry or blow dry the suction head with compressed air.

4、 Maintenance and upkeep

Daily cleaning: Wipe the casing with 75% ethanol to prevent organic solvents from corroding the display screen.

Regular lubrication: Apply specialized silicone grease to the piston every 3 months to reduce friction.

Storage environment: Vertically placed in a dry, non corrosive gas environment, avoiding direct sunlight.

Summary: Proper use of digital pipettes requires standardized operation, skill optimization, and regular maintenance. Avoiding common misconceptions can significantly improve experimental reproducibility, extend equipment lifespan, and safeguard the reliability of scientific research data.