MIDTERM LAB: PIPETTING

Question 1

is filled to a particular graduation, and delivers less the volume

Answer 1

TO CONTAIN

Question 2

will take slightly more than actual volume, but deliver the actual amount

Answer 2

TO DELIVER

Question 3

TYPES OF MICROPIPETTES: BASED ON WORKING PRINCIPLE
 Consists of PISTON which aspirates
& dispenses liquid samples as the
air pocket moves up & down,
respectively
 A disposable pipette tip is used
 Recommended for AQUEOUS
SAMPLES

Answer 3

AIR DISPLACEMENT MICROPIPETTE

Question 4

TYPES OF MICROPIPETTES: BASED ON WORKING PRINCIPLE
 Piston comes in direct contact of
the sample
 Microsyringe composed of
capillary & a piston is used
 Recommended for PROBLEM
SAMPLES

Answer 4

POSITIVE DISPLACEMENT MICROPIPETTE

Question 5

• Aqueous
• Water, sucrose, Tris,
  buffers with pH of 7

RECOMMENDED PIPETTES?

Answer 5

AIR DISPLACEMENT

Question 6

• Biological
• DNA, RNA, proteins

Answer 6

AIR DISPLACEMENT WITH FILTER TOPS

Question 7

• Viscous
• Glycerol, surfactants, oil

Answer 7

POSITIVE DISPLACEMENT

Question 8

• Volatile
• Ethanol, hexane,
  formaldehyde

Answer 8

POSITIVE DISPLACEMENT

Question 9

-Hazardous
- Radioactive isotopes, blood, infectious, bacteria or viruses

Answer 9

POSITIVE DISPLACEMENT

Question 10

Corrosive Acids
- such as hydrochloric acid or sulfuric acid, bases such as ammonium hydroxide salts such as sodium chloride

Answer 10

POSITIVE - DISPLACEMENT

Question 11

OPERATING MECHANISM
 Operate manually based on a
piston – shaft spring mechanism

Answer 11

MECHANICAL MICROPIPETTE

Question 12

 Mostly automated
 Aspirating & dispensing of liquid is
performed by the one – touch
buttons instead of manual plunger
 Piston is motor – driven

Answer 12

ELECTRONIC MICROPIPETTE

Question 13

VARIANTS OF MULTI CHANNEL MICROPIPETTE

Answer 13

8, 12, 16 CHANNEL MICROPIPETTE

Question 14

NUMBER OF CHANNELS
Reduce the workload of a single
channel micropipette when
working with large volumes of
sample

Answer 14

MULTI CHANNEL MICROPIPETTE

Question 15

VOLUME/CAPACITY
 Volume of liquid to be aspirated/dispensed REMAINS FIXED
 Used when the same volume of liquid is to be dispensed multiple times

Answer 15

FIXED VOLUME MICROPIPETTE

Question 16

 Has specific minimum and maximum volume range
 Volume of the liquid to be aspirated/dispensed can be adjusted (within the instrument’s volume range) depending upon the requirement of the user

Answer 16

VARIABLE VOLUME MICROPIPETTE

Question 17

Test tubes and centrifuge tubes are used with ______________________for sample preparations such as qPCR
templates

Answer 17

single channel micropipettes

Question 18

LONG TEST TUBES, also assays tubes, are used with ______________ and __________- with plastic or glass pipettes; these devices are specially designed to reach the bottom of these tubes

Answer 18

positive – displacement pipettes; pipette fillers

Question 19

REAGENT RESERVOIRS are ideal for dispensing reagents, especially with ____________

Answer 19

multichannel pipettes

Question 20

96 – well and 384 – well microplates, as
well as 8 – well strips, are commonly used with _______________ for application like ELISA, but also with single channel pipettes.

Answer 20

air – displacement multichannel pipettes

Question 21

MICROPIPETTE STRUCTURE

Answer 21

1. PLUNGER (PUSH BUTTON)/VOLUME ADJUSTMENT WHEEL (KNOB)
2. TIP EJECTOR
3. VOLUMES WINDOW/VOLUMETER DISPLAY
4. SHAFT
5. DISPOSABLE TIP

Question 22

A ______ angle & ______ immersion depth guarantee the most accurate pipetting result

Answer 22

vertical angle; low immersion depth

Question 23

TO DISPENSE SAMPLE:
Place the pipette tip at angle _______
against the inside wall of the receiving
vessel

Answer 23

(10-45°)

Question 24

PIPETTING TECHNIQUES
Aqueous liquids: buffers, diluted acids/alkali

Answer 24

FORWARD

Question 25

PIPETTING TECHNIQUES
Highly viscous/foaming tendencies

Answer 25

REVERSE

Question 26

WHEN TO CHANGE A TIP?

Answer 26

When transferring a single sample of DIFFERENT LIQUIDS, select a new pipette tip for each new liquid.

Question 27

Leftover portion of sample “A” can mi with the net sample “B” & may cause a false test result

Answer 27

SAMPLE CARRY OVER

Question 28

Store in a clean, cool & dry place ___________(from -4 °F to 120 °F) with relative humidity between _________

Answer 28

(- 20 °C to 50 °C); 5% & 95%;

Question 29

CALIBRATIONS IS DONE EVERY _______

Answer 29

6 MONTHS