This standard applies to pipette use, maintenance and servicing.

2. Content

A complete pipetting cycle includes six steps: tip installation-volume setting-pre-washing tip-aspiration-dispensing-removing the tip. Each step has an operation specification to be followed.

1. Tip installation:

The correct installation method is called the rotary installation method. The specific method is to insert the tip of the white sleeve into the suction head (whether it is a bulk suction head or a boxed suction head), and while gently pressing down, move the handle The liquid container rotates 180 degrees counterclockwise. Remember not to use too much force, let alone the method of chopping the tip, because doing so will cause unnecessary damage to the pipette in your hand.

2. Capacity setting:

The correct capacity setting is divided into two steps, one is coarse adjustment, that is, the capacity value is quickly adjusted to close to its expected value through the discharge button; the second is fine adjustment, when the capacity value is close to its expected value, it should be moved The liquid container is placed horizontally and placed horizontally in front of your eyes, and the volume value is slowly adjusted to the expected value through the adjustment wheel, so as to avoid the effects of visual errors.

When setting the capacity, there is another area that needs special attention. When we adjust from a large value to a small value, it is just fine; but when adjusting from a small value to a large value, we need to adjust more than one third of the circle and then return. This is because there is a certain gap in the counter that needs to be made up.

3. Pre-washed tips:

After we install a new tip or increase the volume value, we should suck and discharge the liquid to be transferred two or three times. This is to make the inner wall of the tip form a homogeneous liquid film to ensure the accuracy of the pipetting work And accuracy, so that the entire pipetting process has a very high reproducibility. Secondly, when absorbing organic solvents or highly volatile liquids, volatile gases will form a negative pressure in the white sleeve chamber, resulting in liquid leakage. At this time, we need to pre-wash four to six times to let the white sleeve chamber When the gas reaches saturation, the negative pressure will automatically disappear.

4. Aspiration:

First press the pipette discharge button to the first stop point, and then immerse the tip vertically into the liquid surface, the immersion depth is: P2, P10 is less than or equal to 1 mm, P20, P100, P200 is less than or equal to 2 mm, P1000 is less than Or equal to 3 mm, P5ML, P10ML is less than or equal to 4 mm (if immersed too deep, hydraulic pressure will have a certain effect on the accuracy of suction, of course, the specific immersion depth should also be flexibly controlled according to the size of the container holding the liquid) , Release the button smoothly, remember not to be too fast.

5. Drain:

When dispensing liquid, the tip is close to the container wall, first press the discharge button to the first stop point, after a short pause, then press to the second stop point, this can ensure that there is no residual liquid in the tip. If there is residual liquid in this operation, you should consider replacing the tip.

6. Remove the tip:

The removed tip must not be mixed with the new tip to avoid cross-contamination.

Two-minute inspection method:

This is a simple method that can be used to quickly check the pipette in the hand. Through the inspection, we can determine whether the pipette in our hands is in a normal working state.

1. Leak detection:

The pipette in our hands is called an air displacement pipette. If there is a leak, our sampling results will definitely not be accurate, which will directly affect the final result of our experiment. The consequences are more serious. . So, how to judge whether the pipette is leaking? This requires us to do a simple test on it. First, take a transparent container and fill it with water. Put the pipette that needs to be tested on the tip and suck up the water. P200 pipette, please immerse the tip into the liquid surface 1-2 mm, wait for 20 seconds, observe whether the liquid level inside the tip drops, if it drops, it means that the pipette in your hand is leaking. Situation; If it is a P1000, P5000, P10ML pipette, hang the tip down for 20 seconds and observe if there is any liquid dripping. If there is, it means that the pipette in your hand is also leaking. What if there is a leak?

2. Find the cause of the fault:

First, check whether the tip is installed properly, replace the tip and test again to eliminate the leakage caused by the relationship of the tip; then, check the port portion of the white sleeve (that is, the portion where the white sleeve contacts the tip) If there are scratches; then, check whether the connecting nut between the white sleeve and the handle is loose. If none of these conditions, it means that the seal ring or piston assembly is damaged, please contact us, we will come to you to solve it.

3. Check the appearance:

Press the discharge button to see if it feels smooth, listen to whether there is noise, and observe whether the discharge rod is bent; rotate the adjustment button to observe whether the reading of the counter deviates.

3. The white sleeve port is downward, gently lift the handle into the tray, press and hold the tail of the piston, put the white sleeve port upward, and place it on the top of the tray. Take out the piston assembly carefully to avoid losing parts;

4. Take the sealing ring from the piston rod or the white sleeve and put it in the tray.

5. Installation, the steps are exactly opposite to disassembly. It should be noted that the black part of the sealing ring faces the white sleeve and the white part faces the handle.

maintenance:

1. Regularly clean the pipette in our hands with alcohol cotton. Mainly wipe the outside of the handle, the ejector and the white sleeve, which can not only keep the appearance beautiful, but also reduce the possibility of contamination of the sample.

2. After absorbing excessively volatile and highly corrosive liquid, the whole pipette should be disassembled, and the piston rod and the inner wall of the white sleeve should be rinsed with distilled water, and then installed after being dried. In order to prevent volatile gas from adsorbing on the surface of the piston rod for a long time, it will corrode the piston rod and damage your pipette.