Volumetric pipette

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Volumetric pipettes are long tubes with a bulb in the middle.
Several sizes of volumetric pipette

A volumetric pipette or bulb pipette allows extremely accurate (of four significant figures) measurement of a volume of 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). Typical volumes are 10, 25, and 50 mL. Volumetric pipettes are commonly used in analytical chemistry to make laboratory solutions from a base stock as well as prepare solutions for titration.

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.[1]

References[edit]

  1. ^ Ainla, A.; Jansson, E. T.; Stepanyants, N.; Orwar, O.; Jesorka, A. (2010). "A Microfluidic Pipette for Single-Cell Pharmacology". Analytical Chemistry 82 (11): 4529–4536. doi:10.1021/ac100480f. PMID 20443547.  edit

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