A pipette (also called a point or a pipettor) is a laboratory instrument used to transfer a measured volume of liquid. Pipettes are commonly used in chemistry and molecular biology research as well as clinical biochemistry tests. Pipettes come in several designs for various purposes with different levels of accuracy and precision, from single piece flexible plastic transfer pipettes to more complex adjustable or electronic pipettes. A pipette works by creating a vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw and dispense liquid.

1. Tapeshwar Yadav
(Lecturer)
BMLT, DNHE,
M.Sc. Medical Biochemistry
PIPETTES AND THEIR SAFELY
USE

2. Introduction:
 A pipette (also called a point or a pipettor) is a
laboratory instrument used to transfer a measured
volume of liquid.
 Pipettes are commonly used in chemistry and
molecular biology research as well as clinical
biochemistry tests.
 Pipettes come in several designs for various purposes
with different levels of accuracy and precision, from
single piece flexible plastic transfer pipettes to more
complex adjustable or electronic pipettes.
 A pipette works by creating a vacuum above the
liquid-holding chamber and selectively releasing this
vacuum to draw and dispense liquid.

4. TYPES:
Depending on the specific purpose they are used
for, and the volume required, various types of
pipettes have been designed.
 Micropipettes: pipettes that dispense between 1
and 1000µl(1ml)
 Macro pipettes: dispense a greater volume of
liquid (more than 1ml).

5. A few of the common types are:
1. Blow out/ Non-blow out pipettes:
 These are the standard laboratory glass pipettes.
 Blow out pipettes have to be fully blown out,
using mouth or otherwise, for dispensing the
measured volume of fluid. No residual fluid
should be allowed to remain.
 Non-blow out pipettes should not be blown
while dispensing. Rubber bulbs (simple, as well
as sophisticated) can be attached to these
pipettes to do away with mouth pipetting. This is
important particularly when handling acids,
alkalis and potentially infected samples as
serum

7. Glass pipettes of different sizes and
specifications

8. 2. Auto-pipettes:
 In these pipettes sucking and blowing with mouth (or other
accessories) is not done.
 These procedures are done using a hand operated
mechanical plunger instead.
 Auto-pipettes can be of 2 types:
 Fixed volume type: Here the volume of fluid sucked in or
dispensed using a pipette is fixed. In other words a pipette
of this type can be used to draw and dispense only a fixed
volume of fluid e.g. 10 µl, 20 µl, 200 µl, 1ml etc. For
measuring different volumes ,one has to use different
pipettes.
 Variable volume type: In this case t,he exact volume of
fluid to be drawn or dispensed can be adjusted using an
adjustment screw, according to the requirement within a
specified range. These pipettes cannot be used beyond
the specified range e.g. 1-10µl, 20-200µl and 100-1000µl.

9. Auto-pipettes

10. 3. Dispensers:
 These are usually used to dispense large fixed
volumes of reagents, within a specified range. It
can be adjusted to dispense a desired volume of
fluid, depending upon the requirement.

11. Method of using a pipette:
 Standard glass pipettes, which are used under
direct eye control, should be used carefully to
ensure accurate measurement (Fluid is sucked a
little above the ‘0’ mark). The index finger should
be applied to seal the top end of the pipette. The
lower meniscus of the fluid should next be
brought to the level of the eye and gradually
released to reach the zero level using the index
finger. Do not use the thumb for this purpose.
 Auto pipettes however should be controlled
with a thumb.
 All plasma or serum samples are considered
infected. Infections can be spread by plasma or
serum.

13. Note: The residual fluid refers to the fluid
remaining in a pipette once the measured
volume of fluid in the pipette is allowed to
move out on its own. The residual volume
cannot be removed without blowing out.
 For safety purposes all serum (or plasma)
samples should be considered infected.
 The required volume of fluid is dispensed (as
determined by the falling fluid level and the
corresponding mark on the pipette) by gently
releasing the pressure exerted by the index
finger.

14. THANK YOU!!!