Pipette Instruction Manual
1. Adjustment of range
Please select a pipette with a suitable range before operation. The pipette can be operated within the range of 10-100% of the range, but the operation at 10% of the range requires high pipetting skills, so it is recommended to be within the range of 35-100% of the range. operate. When adjusting the volume, rotate the knob on the upper part of the pipette with your thumb and index finger. If you want to adjust the volume from a large volume to a small volume, follow the normal adjustment method and turn the knob counterclockwise; but if you want to adjust from a small volume to a large volume , you can first rotate the scale knob clockwise to the scale exceeding the set volume, and then return to the set volume, so as to ensure the highest accuracy of measurement. During this process, do not turn the button out of the range, as this will jam the internal mechanism and damage the pipette.
2. Assembly of the suction head (aspirator)
When putting pipette tips on the pipette, many people tap hard on the tip box a few times. The momentary force of the knock can become loose and even cause the scale adjustment knob to jam. The correct way is to insert the pipette vertically into the tip and turn it slightly left and right to make it tightly combined. For multi-channel (eg, 8 or 12-channel) pipettes, you can align the first channel of the pipette with the first tip, insert it at an angle, and rock it back and forth to snap.
3. Method of pipetting
Before pipetting, ensure that the pipette, tips and liquid are at the same temperature. When sucking liquid, hold the upper part of the pipette with four fingers together, press the button on the top of the plunger rod with your thumb, keep the pipette in a vertical state, insert the tip 2-3 mm below the liquid surface, release the button slowly, Aspirate the liquid, and stay for 1-2 seconds (the solution with high viscosity can prolong the residence time), slide the tip out of the container along the wall of the container, and the tip touches the inclined wall when the liquid is discharged. Wet the tip by pumping and releasing the liquid a few times before suctioning (especially if you are picking up liquids that are viscous or have a different density than water). Finally, push the tip ejector lever to push the tip into the waste bin.
Two pipetting methods:
One is forward pipetting. Press the button with your thumb to the first stop, then slowly release the button to return to the origin. Then press the button to the first stop point to discharge the liquid, stop for a while and continue to press the button to the second stop point to blow out the remaining liquid. Finally release the button.
The second is the reverse pipetting method. This method is generally used to transfer high-viscosity liquids, biologically active liquids, easily foaming liquids or very small liquids. First press the button to the second stop, and slowly release the button to the origin. Then press the button to the first stop point to discharge the liquid with the set range, continue to hold the button at the first stop point (don't press it again), remove the tip with residual liquid, and discard it.
4. Correct placement of pipettes
After use, it can be hung upright on the pipette rack, but be careful not to fall off. When there is liquid in the pipette tip, do not place the pipette horizontally or upside down to prevent the liquid from flowing back and corroding the piston spring.
5. Factors affecting the accuracy of the pipette
(1) Temperature: When the room temperature is low, the hand temperature is high, which makes the air expand, and errors often occur when inhaling the cold solution;
(2) Air tightness: the joint between the tip and the pipette tip, and the long-term wear between the pipette cylinder, cause errors;
(3) Suction speed: it is easy to cause bubbles in the tip, and it will contaminate the pipette tip;
(4) Reagent volatilization: When the highly volatile reagent is sucked, the steam enters the tip, and the internal pressure increases. As a result, when the liquid is squeezed out, the pressure increases, resulting in errors. Solution: 4-5 times of repeated suction can improve.
6. Precautions for the use of pipettes
(1) When sucking the liquid, the thumb must be released slowly and steadily, and it is not allowed to release suddenly, to prevent the solution from being sucked too fast and rushing into the pipette to corrode the plunger and cause air leakage.
(2) In order to obtain higher accuracy, the tip needs to absorb the sample solution once in advance, and then formally pipette, because when the serum protein solution or organic solvent is sucked, a "liquid film" will remain on the inner wall of the tip, resulting in drainage. The amount is too small to cause errors.
(3) Liquids with high concentration and viscosity will cause errors. In order to eliminate the compensation amount of the error, it can be determined by experiment. The compensation amount can be set by changing the reading of the reading window with the adjustment knob.
(4) The pipette can be calibrated by weighing and calculating the weight of the pure water taken with an analytical balance. 1ml of distilled water weighs 0.9982g at 20°C.
(5) It is very inadvisable to tighten the pipette by repeatedly hitting the tip. Long-term operation will loosen the internal parts and damage the pipette.
(6) Do not pipette when the pipette is not equipped with a tip.
(7) When setting the range, please note that the set range is within the range of the pipette and do not turn the button out of the range, otherwise the mechanical device will be stuck and the pipette will be damaged.
(8) The pipette is strictly prohibited to absorb highly volatile and corrosive liquids (such as concentrated acid, concentrated alkali, organic matter, etc.).
(9) Do not use a manual pipette to mix a large volume of liquid.
(10) Do not use a large-scale pipette to remove small volumes of liquid, so as not to affect the accuracy. At the same time, if you need to pipette a larger amount of liquid outside the range, please use a pipette for operation.
(11) If not in use, adjust the range of the pipette to the maximum range, so that the spring is in a relaxed state to protect the spring.
(12) It is best to clean the outer wall of the pipette regularly. You can wipe it with soapy water or 60% isopropyl alcohol, then wash it with distilled water and dry it naturally.
(13) Before high temperature sterilization, make sure that the pipette can adapt to high temperature.
(14) Calibration can be carried out by repeating the method of weighing distilled water several times in an environment of 20-25 degrees.
(15) Check whether there is liquid leakage during use. The method is to place it vertically in the air for a few seconds after absorbing the liquid.
See if the liquid level drops. If there is leakage, the reasons are roughly as follows:
Whether the suction head matches;
Whether the spring piston is normal;
If it is a volatile liquid (as is the case with many organic solvents), it may be a problem with saturation vapor pressure. You can aspirate the liquid a few times before pipetting.
(16) When the volume of the pipette is locked, do not adjust the volume, so as not to damage the internal parts of the pipette.
(17) When using the pipette, do not over-suction. The liquid entering the pipette will easily dilute or contaminate the internal lubricating oil, which will cause the pipette to be unsmooth and not easy to rebound. Long-term use may easily cause wear and tear of accessories. .
(18) The pipette needs to be maintained and calibrated to ensure better accuracy after half a year to one year of normal use.
