How to Use the Pipette?
Pipette gun is a kind of pipette, which is often used to pipe small or trace liquids in the laboratory. Pipettes of different specifications use different sizes of tips. The shapes of products produced by different manufacturers are slightly different, but the working principles and operating methods are basically the same. The pipette belongs to a precision instrument, so it is required to be careful when using and storing it to prevent affecting the measurement range caused by damage.
When conducting research on analysis and test, the pipette is generally used to measure and take small or trace liquids. Many people will ignore the correct operation means of the pipette and some detailed operations. The next paragraph will explain how to use the pipette correctly.
In adjusting the range, if it is to adjust from large volume to small volume, the normal regulation means shall be followed, which means to rotate the knob in the clockwise direction. However, if it is to adjust from the small volume to large volume. Firstly, it can turn the scale knob in counterclockwise direction to the scale that exceeds the range, and then return to the set volume, so as to ensure the accuracy of the measurement.
During this process, never turn the button out of the range, otherwise it will jam the internal mechanical device and damage the pipette.
Before pipetting, it is required to make sure that the pipette, pipette tip and liquid are at the same temperature. In sucking liquid, the pipette must be kept in an upright position and the pipette tip shall be inserted 2-3 mm below the liquid surface. Before sucking the liquid, it is recommended to suck and release the liquid for several times to wet the suction nozzle (especially when it is going to suck liquid with a viscosity or when the density is different from water). At this time, two pipetting methods can be used:
The first is the forward pipetting method. Press the button to the first stop with the thumb and then slowly release the button to the original point (suck the liquid of the fixed volume), and then press the button to the first stop point to drain out the liquid, wait for a while, continue to press the button to the second stop point to blow out the residual liquid, and release the button in the end.
The second is the reversed pipetting method, which is usually used to transfer high-viscosity liquid, biologically active liquid, foaming liquid or very small amount of liquid. The principle is to suck in more liquid than the set range first. There is no need to blow out the remaining liquid when transferring liquid. First press the button to the second stop point, slowly release the button to the origin, suck in the liquid and lean against the container wall to flow the excess liquid back to the container along the wall, press the button to the first stop to discharge the liquid with the set range, keep holding the button at the first stop (avoid pressing it down again), remove the tip of the gun with residual liquid, leaning against the container wall to flow the excess liquid back to the container along the wall.
After use, it can be hung vertically on the pipette holder. However, be careful not to fall off. When there is liquid in the pipette tip, don’t place the pipette horizontally or upside down to prevent the liquid from flowing back and corroding the piston spring.
How to use the electronic pipette controller?
Select the appropriate electronic pipette controller
When pipetting standard solutions (such as water, buffer solutions, diluted salt solutions and acid-base solutions), an air displacement pipette is frequently used. When pipetting liquids with high volatility, high viscosity, and density greater than 2.0g/cm, or when adding samples in clinical polymerase chain reaction (PCR) assays, forward displacement pipettes should be used. If pipetting 15ul of liquid, it is preferential to choose a pipette with a maximum volume of 20ul. Pipettes with a range of 50ul and above aren't accurate enough.
Set the pipetting volume
The pipetting volume can be set by adjusting the pipetting volume control knob of the pipette. When adjusting the pipetting volume, the rotary scale of the volume size should be jumped to a scale exceeding the set volume, and then return to the set volume, so as to ensure the best accuracy of pipetting.
Assemble the sucker
When using a single-channel pipette, align the mouth of the adjustable pipette with the nozzle of the tip, and press it down gently and firmly to tighten it. When using a multichannel pipette, align the first row of the pipette with the first nozzle, insert it at an angle, and then slightly shake it back and forth to tighten.
First of all, the pipette, tip and the liquid to be pipetted shall be maintained at the same temperature, and then it is required to rinse the pipette tip with the suction liquid to be piped for 1-2 times, especially for viscous liquids or liquids with a density different from water. When pipetting the liquid, immerse the tip of the tip vertically into a depth of 2-3mm below the liquid surface (it is strictly forbidden to insert the entire pipette tip into the solution), loosen the operating rod slowly and evenly, wait 2-3 seconds after the tip has absorbed the solution, and obliquely stick to the container wall to absorb the excess liquid on the outer wall.
Placement of the pipette
After using the pipette, the push rod of the sucker shall be pressed down with the thumb, adjust the volume to the maximum volume after exiting the sucker safely, and then suspend the pipette on the special rack. The pipette shall be placed in an exclusive box if it is not going to be used for a long time.