[1S] UNIT 3: Pipetting

Question 1

➢ glass or plastic tubes
➢ open at both ends
➢ transfer specific amounts of liquid from one
container to another.
➢ usually used for volumes between .01 and 10
milliliters.

Answer 1

Pipettes

Question 2

TYPE 1: ACCORDING TO DESIGN

Water is used for calibration. Allow liquid to flow by gravity, don’t blow. For non-viscous liquids

Answer 2

To deliver

Question 3

TYPE 1: ACCORDING TO DESIGN

Hg is used for calibration. Exact volume is delivered by repeated filling and emptying with the diluents. For viscous liquids

Answer 3

To contain

Question 4

TYPE 2: ACCORDING TO DRAINAGE CHARACTERISTIC

• similar to TD pipet
• Last drop is blown out to get the exact volume
• An etched or frosted ring indicate calibration

Answer 4

To blow out pipet

Question 5

TYPE 2: ACCORDING TO DRAINAGE CHARACTERISTIC

contents are allowed to drain by gravity

Answer 5

Self draining

Question 6

TYPE 3: MEASURING / GRADUATED PIPETS

has calibration marks to the tip and is generally a blow-out pipet

Answer 6

Serologic

Question 7

• capable of dispensing different volumes
• Uniform graduation along its length
• Deliver fractional quantity of liquid
• Used for reagent measurements

Answer 7

Measuring or Graduated pipets

Question 8

TYPE 3: MEASURING / GRADUATED PIPETS

does not have graduations to the tip, self draining

Answer 8

Mohr

Question 9

TYPE 3: MEASURING / GRADUATED PIPETS

may either be a serological or mohr. Calibrated either TC or TD. With total holding volume of less than 1 ml.

Answer 9

Micropipet

Question 10

Printed on the neck of the pipette are the specifications that indicate:

Answer 10

1. maximum volume of liquid that can be transferred
2. size of the divisions on the pipette
3. temperature at which calibrations were made
4. if the pipette is a “to deliver”(TD) or “to contain”(TC)
   pipette.

Question 11

designed to dispense one volume

Answer 11

Transfer Pipets

Question 12

TYPE 3.B: TRANSFER PIPETS

• has a cylindrical bulb located midway between the mouth and the tip.
• calibrated TD a fixed volume of liquid
• allowed to drain only

Answer 12

Volumetric

Question 13

TYPE 3.B: TRANSFER PIPETS

• used for accurate measurement & other non-viscous fluids
• has the greatest accuracy & precision
• deliver a single specific volume of liquid, usually
between 1 and 10 ml.

Answer 13

Volumetric

Question 14

TYPE 3.B: TRANSFER PIPETS

• For accurate measurements
• Deliver one volume only

Answer 14

Volumetric

Question 15

SPECIFICATIONS ON A VOLUMETRIC PIPETTE

T/F: 1. When emptying a volumetric pipette, the liquid is not allowed to drain out. It is forced out.

Answer 15

F; When emptying a volumetric pipette, the liquid is allowed to drain out. It is NOT forced out.

Question 16

SPECIFICATIONS ON A VOLUMETRIC PIPETTE

T/F: 2. After it is emptied, the small amount of liquid which remains in the tip should not be blown out.

Answer 16

T

Question 17

SPECIFICATIONS ON A VOLUMETRIC PIPETTE

T/F: Volumetric pipettes are NOT blow-out pipettes

Answer 17

T

Question 18

TYPE 3.B: TRANSFER PIPETS

• bulb is located closer to the delivery tip
• with an etched ring/blow-out pipet
• used to measure viscous fluid

Answer 18

Ostwald-Folin Pipet

Question 19

TYPE 3.B: TRANSFER PIPETS

have no calibration marks and are used to transfer solutions or biologic fluids without consideration of a specific volume.

Answer 19

Pasteur pipet

Question 20

TYPE 3.B: TRANSFER PIPETS

most routinely used.
Advantages: safety, stability, ease of use, increased
precision, saves time, less cleaning is required.

Answer 20

Automatic pipets

Question 21

AUTOMATIC PIPETS

1. associated with 1 volume
2. ranges from 1ul to 1000 ml

Answer 21

1. fixed
2. variable

Question 22

AUTOMATIC PIPETS

has a pipetting capability of less than 1 ml

Answer 22

Micropipet

Question 23

AUTOMATIC PIPETS

dispenses greater than 1 ml

Answer 23

Automatic macropipet

Question 24

GENERAL TYPES OF AUTOMATIC PIPETS

relies on a piston for suction creation to draw the sample into a disposable tip that must be changed after each use.

Answer 24

Air Displacement

Question 25

GENERAL TYPES OF AUTOMATIC PIPETS

operates by moving the piston in the pipet tip or barrel, much like a hypodermic syringe. Does not require different tip for each use. Requires rinsing and blotting between samples to prevent carryover.

Answer 25

Positive Displacement

Question 26

GENERAL TYPES OF AUTOMATIC PIPETS

automatic pipets that obtain the liquid from a common reservoir and dispense it repeatedly. The dispensing pipets may be bottle –top, motorized, handheld or attached to a dilutor.

Answer 26

Dispensers and Dilutors