LAB GLASSWARE

Question 1

Tolerance and accuracy

Answer 1

Limits of error; nearness to the true value

Question 2

Precision and reproducibility

Answer 2

Ability to repeatedly produce the same value

Question 3

Capacity in terms of glassware

Answer 3

Volume the glassware will hold or deliver

Question 4

Temperature in regards to glassware

Answer 4

Temp the glassware was calibrated and temp to be used at

Question 5

What’s the average temperature for glassware to be calibrated at?

Answer 5

20c

Question 6

Liquid ____ when warmed.

Answer 6

Expands

Question 7

Liquid ____ when cooled.

Answer 7

“Contracts”

Question 8

TC?

Answer 8

To contain

Question 9

What does TO CONTAIN mean?

Answer 9

Holding a specific volume

Question 10

TD?

Answer 10

To deliver

Question 11

What does TO DELIVER mean?

Answer 11

Holding a bit more than what is stated; this is to deliver the stated amount

Question 12

What is prepared in TC glassware?

Answer 12

Solutions

Question 13

What are some examples of TC glassware?

Answer 13

Volumetric flasks

Question 14

What glasswares are TD?

Answer 14

Pipettes and some graduated cylinders

Question 15

Where should the meniscus be?

Answer 15

The lowest part of the meniscus should be ON the calibration mark.

Question 16

What are volumetric flasks primarily used for?

Answer 16

Preparation of accurate solutions — reagents and controls

Question 17

What are cylinders used for?

Answer 17

Prepare solutions that require less accuracy — ex. Cleaning solutions

Question 18

Are cylinders TC or TD?

Answer 18

Both

Question 19

What are examples of glassware that aren’t calibrated TC or TD—graduation marks are approximations?

Answer 19

Beakers, Erlenmeyer flasks, test tubes, and reagent bottles

Question 20

Volumetric pipettes are ____ (TC/TD).

Answer 20

TD

Question 21

Which is the most accurate pipette?

Answer 21

Volumetric

Question 22

What are some examples of graduated/measuring pipettes?

Answer 22

Mohr and serological

Question 23

What’s the difference between a Mohr and serological pipette?

Answer 23

Mohr pipettes aren’t calibrated at the tip while serological pipettes are.
Serological pipettes aren’t wiped with a tissue!

Mohr - you discard the liquid at the tip
Serological - you blow out the last drop

Question 24

What’s the ranking of pipettes in terms of accuracy?

Answer 24

Volumetric
Mohr
Serological
Pasteur

Question 25

What are serological pipettes used for?

Answer 25

Serial solutions; measuring thick liquids; procedures where accuracy doesn’t matter

Question 26

What are semiautomatic pipettes used for?

Answer 26

The measuring of small volumes (1uL - 1000uL).

Question 27

What are good techniques for using semiautomatic pipettes?

Answer 27

- pipette held vertically - smooth depression and release of plunger - depress plunger before inserting into sample - when transferring to a receiving tube, don’t release plunger till you remove from receiving tube

Question 28

What are examples of semiautomatic pipettes?

Answer 28

MLA pipettes, and Eppensorf/Hamilton pipettes

Question 29

What’s the difference between a MLA pipette and an Eppendorf/Hamilton pipette?

Answer 29

The eppendorf/Hamilton pipette’s plunger has two stops

Question 30

How do you proper usage of the two stops on an eppendorf/Hamilton pipette?

Answer 30

- first stop for picking up sample | - depress plunger to first stop when transferring to receiving tube, wait one second then depress to second stop

Question 31

How do you maintain a MLA pipette?

Answer 31

- Clean and lubricate the piston every 3 months. - apply thin coat of silicone to piston. - replace seal if pipette doesn’t pick up or discharge samples - clear nozzle with compressed air jet or fine wire if clogged - calibrate

Question 32

How often should calibration and quality control checks be done on eppendorf/Hamilton pipettes?

Answer 32

Every 6 months or after maintenance

Question 33

What are some examples given for specialty pipettes?

Answer 33

Repeater, multi-tip, and digital

Question 34

What are repeater pipettes?

Answer 34

Pipettes that draw up a large volume, and dispenses some into multiple tubes

Question 35

What are multi-tip pipettes?

Answer 35

Pipettes that have many tips attached to one pipette to deliver the same volume into multiple sample cups at once

Question 36

What are digital pipettes?

Answer 36

Pipettes that have digital volume displays

Question 37

How do you check if glassware is physically clean?

Answer 37

Water will uniformly wet the surface of the glass

Question 38

How do you check if glassware is chemically clean?

Answer 38

By measuring the pH of water added to the glassware | Or by adding dilute indicator to the surface of the glass

Question 39

How many rinses with tap water do you need to do to manually clean glassware?

Answer 39

7-10

Question 40

How many rinses do you need to do with distilled water when manually cleaning glassware?

Answer 40

3

Question 41

How many cycles does the laboratory glassware washers have?

Answer 41

6

Question 42

What are the six cycles the laboratory washer goes through?

Answer 42

1. Pre-rinse 2. Detergent wash 3, 4, 5. First, second, and third rinses 6. Distilled or deionized water rinse