Use and verification of pipettes

A pipette, also known as a pipette gun, is a commonly used tool for quantitatively transferring liquids. It is widely used in fields such as biology and chemistry, as well as clinical diagnostic laboratories, biotechnology laboratories, pharmaceutical and chemical laboratories, environmental laboratories, and food laboratories. There are two types of commonly used tools: manual adjustable pipettes and electric ones. There are also many optional specifications depending on the volume of the liquid being transferred.

The pipette is easy to operate and can greatly improve the efficiency of inspection and detection compared to glass pipettes, which is favored by experimental workers in food and drug inspection institutions; However, there has always been a tendency to prioritize the use and neglect management of pipettes. Most laboratory inspectors directly use adjustable pipettes without training, and the verification cycle for pipettes during most laboratory inspections is one year or half a year. It should be noted that the systematic errors caused by the environment and operation of the pipette are extremely significant, which may ultimately lead to deviations in the detection results.

Let's take a look at the use, maintenance, and precautions of the pipette:

Usage of pipette

A complete pipetting cycle, including steps such as installing the suction head - setting the capacity - suction and discharge - removing the suction head. Each step has operational guidelines to follow.

Installation of suction head

For a single pipette, the end of the pipette is vertically inserted into the suction head, and lightly pressed left and right to rotate slightly to tighten;

For a multi-channel pipette, align the first pipette with the first suction head, insert it obliquely, and shake it back and forth slightly to tighten it.

Do not repeatedly hit the pipette to ensure the airtightness of the suction head. Assembling the suction head in this way for a long time can cause the components of the pipette to loosen due to strong impact, and even cause the knob for adjusting the scale to get stuck.

Capacity setting

When adjusting from large volume to small volume, rotate counterclockwise to the scale; When adjusting from a small volume to a large volume, the set volume can be adjusted clockwise first, and then adjusted back to the set volume to ensure the best accuracy.

Do not rotate the adjustment knob outside the range, otherwise it may damage the mechanical device inside the pipette.

Aspiration and discharge

Press the suction pipette button to the first position, release the button, and perform suction. Remember not to move too quickly, otherwise the liquid entering the suction head too quickly may cause the liquid to be sucked back into the inside of the pipette.

Place the liquid tightly against the container wall, first press to the first position, pause slightly, and then press to the second position to remove any remaining liquid.

● Vertical suction.

5ml and 10ml pipettes, the suction head needs to be immersed in the liquid level for 5mm, slowly suck the liquid, reach the predetermined volume, pause below the liquid level for 3 seconds, and then leave the liquid level.

Slowly release the controller when aspirating, otherwise the liquid entering the suction head too quickly may cause the liquid to be sucked back into the inside of the pipette

When absorbing volatile liquid, it is necessary to wet the suction head 4-6 times to saturate the steam inside the sleeve chamber, which can avoid liquid leakage.