The P is reads differently. The display from the top down reads, hundreds, tens, ones, and the vertical lines are considered 0. Finally, the P can be read from the top down tens, ones, and the red tenths. For each amount listed below, indicate the correct micropipette needed to measure the volume accurately then set the pipette to the indicated amount and show your partner.
Take a picture or draw a picture of your spots and include this in your lab notebook as Figure 1. Make sure the figure has a title. Labeled parts of a micropipette, front and back. Figure 2. Reading a micropipette at various sizes. Choosing your Micropipette For each amount listed below, indicate the correct micropipette needed to measure the volume accurately then set the pipette to the indicated amount and show your partner. Table 1. Setting your Micropipette Materials P micropipette P tips Waste container Tube of red dye in tube rack Laminated sheet for pipetting.
Hold the micropipette in your dominant hand, and gently but securely place the end of the micropipette into the proper size tip. Once the tip is on, be careful not to touch the tip on anything! If your tip touches the bench, lab coat etc. With your other hand, open the cap of the tube of red dye and bring the tube of red dye to eye level, Push the micropipette plunger down to the first stop and hold your thumb in this position. Place the pipet tip into the red dye solution. Gently release your thumb from the plunger to draw fluid into the tip.
Confirm that the tip has liquid and that no bubbles are present within the tip. The standard deviation for a set of n measurements is calculated using the formula below. We use three different sizes of micropipettes in the laboratory, the P20, P and P Our micropipettes have been purchased from several different manufacturers, but the principles of operation are the same.
Note that there is some overlap in the ranges of the different micropipettes. As a rule of thumb, always select the smallest volume pipette that will transfer the desired volume.
There are three numbers on the volume indicator. With each of the micropipettes, you will specify a volume to three digits by turning the volume adjustment knob. You will also be able to extrapolate between the lowest numbers with the vernier marks on the lower dial. Most of the measurements you will make with the micropipettes will be accurate to four significant figures! NEVER turn the indicator dial beyond the upper or lower volume limits of the micropipette!
This could damage the piston. Micropipettes work by air displacement. The operator depresses a plunger that moves an internal piston to one of two different positions. The first stop is used to fill the micropipette tip, and the second stop is used to dispense the contents of the tip. As the operator depresses the plunger to the first stop, an internal piston displaces a volume of air equal to the volume shown on the volume indicator dial.
The second stop is used only to dispense the contents of the tip. Standard deviation describes the distribution of measurements relative to the mean value. Choosing the micropipette. Volume indicators on the P, P and P micropipettes. The top digit on the P red on some models indicates milliliters and the bottom digit on the P red on some models indicates tenths of microliters. A micropipette is the most essential tool used in a molecular biology laboratory.
When paired with disposable plastic pipette tips, a micropipette is used to measure out very small amounts of liquid. To use a micropipette, the user must learn how to properly change the volume setting, add a tip, obtain a sample, dispense a sample, and dispose of the tip. A micropipette can come in one of many standard sizes, and the most common can measure out a volume between 0.
This is 0. Just as milliliters is equal to 1 liter, microliters is equal to 1 milliliter. Each micropipette only works effectively within a certain range, and each volume variance of pipette looks very similar to each other.
To avoid confusion, manufacturers label the plunger of the micropipette with the maximum volume it can accurately dispense. Due to standardization across manufacturers however, the minimum volume for each micropipette is the same unless otherwise stated. Look at the table below for the five most common micropipette types and ranges.
Type of Micropipette Typical Range of Use. P10 0. P20 2. P On the body of the micropipette is a small vertical window with three numbers.
These numbers, read from the top down, tells the user how much volume the micropipette is currently set at. To change the numbers, grasp the black dial or plunger and gently twist. The numbers will then change. Twisting the black volume dial too far in either direction can damage or destroy the micropipette.
Even though the dial numbers look identical between the different sizes of micropipettes, remember that they will dispense different amounts of solution. On a P2 a reading of will dispense 1. Some micropipettes will indicate tenths and hundredths of a microliter in red on the lowest number on the body of the pipette. Because of this, different micropipettes will use different size tips.
There are three different size tips that can have different colors. White tips fit onto P2 and P10 pipettes. Yellow tips fit onto P20 and P pipettes. Blue tips fit onto P pipettes. To add the tip to the micropipette, leave the tip in the tip box, then firmly press the end of the micropipette into the wide end of the tip. Pull up, and it should be attached. A firm seal between tip and pipette is important, otherwise the amount of solution that you draw up will be inaccurate.
If the tip falls off, throw it away. A sterile tip is necessary for experiments, otherwise contamination will ruin your result.
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