Bulb/Graduated pipettes is a pipette with its volume, in increments, marked along the tube. It is used to accurately measure and transfer a volume of liquid from one container to another. It is made from plastic or glass tubes and has a tapered tip.
- All Bulb/Graduated Pipettes are manufactured according to DIN ISO 648 Standards.
- These pipettes are calibrated to deliver (TD, EX) +20 Deg C;
- All pipettes are calibrated on a computerized machine before being rechecked by the quality control centre
- Complies to ISO 835 Standard
- With batch certificate
A volumetric pipette, bulb pipette, or belly pipette allows extremely accurate measurement (to four significant figures) of the volume of a solution. These pipettes have a large bulb with a long narrow portion above with a single graduation mark as it is calibrated for a single volume (like a volumetric flask).
A graduated pipette is a pipette with its volume, in increments, marked along the tube. It is used to accurately measure and transfer a volume of liquid from one container to another. It is made from plastic or glass tubes and has a tapered tip. Along the body of the tube are graduation markings indicating volume from the tip to that point. A small pipette allows for more precise measurement of fluids; a larger pipette can be used to measure volumes when the accuracy of the measurement is less critical.
Graduated pipettes are manufactured according to ISO specifications for accuracy and the arrangement of the graduations. Grade A and AS pipettes have the highest accuracy. These allowed error ranges are identical to those of the DIN EN ISO standards. Grade B pipettes generally have twice the allowed error as grade A and AS pipettes.
These pipettes commonly come in 5, 10, 25, and 50 mL volumes. A variety of pro-pipetters have been developed, both entirely manual and electrically assisted. Originally pipettes were made of soda-lime glass, but currently many are made of borosilicate glass
How to use the pipette
The recommendation is for using a pipette whose size is nearest to the volume being worked with. Rinsing the pipette before use is required to prevent error.
The standard technique for handling a graduated pipette is to hold the pipette tip dipped in the solution without touching the bottom of the beaker.
Then use a pipette pump or pipette filler, to draw the liquid into the pipette. The effective way to control the volume of the solution is to use one’s forefinger. After getting the desired volume, the solution can be released into another vessel by lifting the finger. During pipetting, the pipette must not be held other than upright.
The solution will form a meniscus, whose position is read according to the scale printed on the pipette. For high viscosity liquids, the volume is measured by looking at the upper meniscus. For low viscosity liquids, the volume is measured by looking at the lower meniscus.
