Volumetric pipettes
Encyclopedia
A Volumetric pipette is a tool for measuring precise volumes of a liquid
. Pipette
s are typically long tubes, open on both ends, marked to contain (or deliver) a certain volume of liquid.
They are commonly used in analytical chemistry
to make up diluted solutions by measuring out a known volume of the concentrated stock solution, or to measure out a known volume of a solution to be titrated
.
Volumetric pipettes are typically calibrated for only one volume (e.g., 5.00 mL). Many different sizes are available.
ASTM standard E969 defines the standard tolerance for volumetric transfer pipettes. The tolerance depends on the size: a 0.5-mL pipette has a tolerance of ±0.006 mL, while a 50-mL pipette has a tolerance of ±0.05 mL. (These are for Class A pipettes; Class B pipettes are given a tolerance of twice that for the corresponding Class A.)
A specialized example of a volumetric pipette is the microfluid pipette (capable of dispensing as little as 10µL) designed with a circulating liquid tip that generates a self-confining volume in front of its outlet channels.
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
. Pipette
Pipette
A pipette is a laboratory tool used to transport a measured volume of liquid.-Use and variations:Pipettes are commonly used in molecular biology, analytical chemistry as well as medical tests...
s are typically long tubes, open on both ends, marked to contain (or deliver) a certain volume of liquid.
They are commonly used in analytical chemistry
Analytical chemistry
Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample and quantitative analysis determines the amount of...
to make up diluted solutions by measuring out a known volume of the concentrated stock solution, or to measure out a known volume of a solution to be titrated
Titration
Titration, also known as titrimetry, is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of an identified analyte. Because volume measurements play a key role in titration, it is also known as volumetric analysis. A reagent, called the...
.
Volumetric pipettes are typically calibrated for only one volume (e.g., 5.00 mL). Many different sizes are available.
ASTM standard E969 defines the standard tolerance for volumetric transfer pipettes. The tolerance depends on the size: a 0.5-mL pipette has a tolerance of ±0.006 mL, while a 50-mL pipette has a tolerance of ±0.05 mL. (These are for Class A pipettes; Class B pipettes are given a tolerance of twice that for the corresponding Class A.)
A specialized example of a volumetric pipette is the microfluid pipette (capable of dispensing as little as 10µL) designed with a circulating liquid tip that generates a self-confining volume in front of its outlet channels.