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Pipettes and Their Safely Use

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.

Pipettes and Their Safely Use

  1. 1. Tapeshwar Yadav (Lecturer) BMLT, DNHE, M.Sc. Medical Biochemistry PIPETTES AND THEIR SAFELY USE
  2. 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.
  3. 3. 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).
  4. 4. 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
  5. 5. Glass pipettes of different sizes and specifications
  6. 6. 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.
  7. 7. Auto-pipettes
  8. 8. 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.
  9. 9. 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.
  10. 10. 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.
  11. 11. THANK YOU!!!

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