Pipetting Technique and Centrifugation (P)

Question 1

What is pipetting technique?

Answer 1

A technique used to transfer aliquot of liquid sample from one container to another

Question 2

What are the different types of pipettes?

Answer 2

1) According to Design
2) According to Drainage
3) According to Type

Question 3

What are the different types of pipettes under according to design type of pipette?

Answer 3

1) To contain (TC)

2) To deliver (TD)

Question 4

What is TC?

Answer 4

TC pipette holds or contains a particular volume but does not dispense that exact volume

Question 5

What is TD?

Answer 5

TD will dispense the volume indicated

Question 6

What type of pipette under according to design type is more common?

Answer 6

TD pipettes are more common than TC pipettes

Question 7

What are the different types of pipettes under according to drainage type of pipette?

Answer 7

1) Blow-out

2) Self-draining

Question 8

What is the characteristic of blow-out pipette?

Answer 8

Blow-out pipette has frosted bands or two continuous rings or etched rings at the top

Question 9

What should be done when blow-out pipette is used?

Answer 9

The last drop is fully expelled into the receiving vessel

Question 10

What should be used when expelling the last drop of liquid or reagent in blow-out pipette?

Answer 10

Aspirator bulb

Question 11

What is self-draining pipette?

Answer 11

The contents of self-draining pipette are drained by gravity

Question 12

What are the types of pipette under according to type pipettes?

Answer 12

Measuring or Graduated

Question 13

What are the functions of measuring or graduated pipettes?

Answer 13

Used to transfer reagents and make dilutions

Used to dispense several volumes

Question 14

What are the 3 types of measuring or graduated pipettes?

Answer 14

1) Serologic
2) Mohr
3) Micropipette

Question 15

What are the characteristics of serologic pipette?

Answer 15

1) The graduations are located after the tip of the pipette

2) It is a blow-out pipette

Question 16

What is a Mohr pipette?

Answer 16

1) The graduations are located before the tip of the pipette

2) It is a self-draining pipette

Question 17

What is the volume capacity of micropipette?

Answer 17

< 1 mL

Question 18

Can micropipettes be designed as serologic or Mohr pipette?

Answer 18

Micropipettes can be designed as either serologic or Mohr pipette

Question 19

What are micropipettes?

Answer 19

Micropipettes are the small version of measuring pipettes

Question 20

Is the total volume of a pipette indicated in the pipette (measuring or graduated) itself?

Answer 20

Yes, including the dilutions or major divisions where the specific pipette can be used

Question 21

What are the 4 types of transfer pipettes according to type?

Answer 21

1) Volumetric
2) Ostwald-Folin
3) Pasteur pipettes
4) Automatic pipettes

Question 22

What is the general term for all types of pipettes under according to type?

Answer 22

Transfer pipette

Question 23

What is a transfer pipette?

Answer 23

It dispenses one volume without further subdivisions

Question 24

What are the characteristics of volumetric pipette?

Answer 24

1) It carries aqueous solutions
2) Most accurate and precise
3) Self-draining

Question 25

What are the characteristics of Ostwald-Folin pipette?

Answer 25

1) It carries viscous fluid | 2) Blow-out

Question 26

What are Pasteur pipettes?

Answer 26

It is the disposable type of pipette

Question 27

When are automatic pipettes used?

Answer 27

Automatic pipettes are routinely used in the CC lab

Question 28

What are the 2 types of automatic pipettors?

Answer 28

1) Micropipettes | 2) Macropipettes

Question 29

What is the volume capacity of micropipettes?

Answer 29

< 1 mL

Question 30

What is the volume capacity of macropipettes?

Answer 30

1 mL >

Question 31

What are the materials needed for (serological pipetting) pipetting?

Answer 31

1) Serological pipette 2) Aspirator bulb 3) Automatic pipettors 4) Beaker (50 mL) 5) Distilled H2O

Question 32

What is the procedure of using serologic pipettes?

Answer 32

1) Rinse the pipette twice (2x) with distilled water. 2) The pipet should be held upright. Immerse the tip in the liquid to be transferred without touching the vessel walls. 3) Use an aspirator/pipet bulb, apply a slight suction until the liquid enters the pipet. 4) When the MENISCUS is brought above the desired graduation line (ASPIRATION), stop the suction. 5) Quickly place your dry index finger over the upper opening of the pipette to control the flow of liquid. 6) Wipe with a tissue of any adhering liquid. 7) Prepare your receiving vessel/beaker. 8) Adjust the contents to desired volume by gently releasing the finger

Question 33

What are the parts of an automatic pipettor?

Answer 33

1) Push button (or plunger) 2) Ergonomic grip cover 3) Tip ejector 4) Digital display 5) Tip ejector collar 6) Tip cone

Question 34

How to use an automatic pipettor?

Answer 34

1) Adjust to the desired volume. 2) Get a pipette tip from a pipette tip rack. 3) Hold the pipette in a vertical position. 4) Depress the plunger to the FIRST STOP. 5) Immerse the pipette tip (HALF) into the liquid. 6) Release the plunger to aspirate liquid sample. 7) Depress the plunger all the way to the SECOND STOP to transfer it to the receiving vessel. 8) Allow the plunger to move up to the rest position. 9) Eject the tip (ejector tip)

Question 35

What are the considerations that should be observed for proper care of automatic pipettes?

Answer 35

1) Store pipettes vertically to avoid contamination 2) Store pipettes dialed to the lowest volume setting 3) Store away from heat and moisture 4) Pipette tips should be removed prior to storage 5) Calibration should be done (3 - 6 mos according to CLSI) 6) When cleaning pipettes with bleach solution, do not saturate as fluid can make its way to the piston and cause corrosion

Question 36

What is centrifugation?

Answer 36

It is the process in which centrifugal force is used to separate solid matter (sediment) from a liquid suspension

Question 37

What is the expression (or unit) for the speed in centrifugation?

Answer 37

It is expressed in revolutions per minute (RPM)

Question 38

What are the 2 types of speed in centrifugation?

Answer 38

1) Low-speed | 2) High-speed

Question 39

What is the speed under low-speed in centrifugation?

Answer 39

0 - 7,500 RPM

Question 40

What is the speed under high-speed in centrifugation?

Answer 40

20,000 RPM >

Question 41

What are the parts of a digital centrifuge?

Answer 41

1) Automatically electric (or eletric?) lid lock 2) Rotor - > 4 x 800 mL swing rotor 3) Model 4) Stop 5) Start 6) Logo 7) Program - > 10 kinds (depending on your choice) 8) Deceleration 9) Acceleration 10) Speed

Question 42

What should be done to acquire proper counterbalancing?

Answer 42

1) Ensure all sample tubes are evenly filled. 2) For each tube inserted in the rotor, add a tube of equal weight directly opposite it. This will ensure the center of gravity remains in the center of the rotor. 3) Make sure to take note of the positioning in the rotor

Question 43

How to operate a centrifuge (bench-top model)?

Answer 43

1) The work surface must be level and firm 2) Connect to a power supply 3) Counterbalance the tubes in the rotor 4) Adjust the speed 5) Set the timer 6) Click start 7) Wait for the centrifuge to reach its full stop (beep sound) 8) Open the lid. Use goggles or shields 9) Take out the sample tubes 10) Close the lid and perform cleaning of the centrifuge

Question 44

What are the considerations that should be done when it comes to care and maintenance of centrifuge?

Answer 44

1) Ensure all users are aware of how to properly operate the centrifuge 2) Inspect critical components, and look for signs of wear including scratches, or effects of chemical exposure on the rotor 3) Pay close attention to noise, vibration, shaking, or grinding, and stop the unit immediately if this occurs 4) Regularly clean the centrifuge with neutral cleaning solutions (alcohol or alcohol-based disinfectant) applied with a soft cloth to rotors and accessories