Field Instruments

Question 1

Catalytic Hot Wire Application

Answer 1

Flammable and combustible hydrocarbons, petroleum distillates

Question 2

Catalytic Hot Wire Advantages

Answer 2

Cheap, simple, may be used to indicate low ppm thru explosive range concentrations

Question 3

Catalytic Hot Wire Disadvantages

Answer 3

Easily poisoned by lead and silicon compounds, poor response to oxygenated compounds, no response to halocarbons

Question 4

Thermal Conductivity Application

Answer 4

H, He, vapors w/ different thermal conductivity (MW) from air

Question 5

Thermal Conductivity Advantages

Answer 5

Inexpensive, may be used to detect low ppm through 100% concentration range, not poisoned by reactive gas

Question 6

Thermal Conductivity Disadvantages

Answer 6

Non specific, simplest application qualitative only

Question 7

Flame Ionization Detector Application

Answer 7

Flammable and combustible hydrocarbons, petroleum distillates

Question 8

Flame Ionization Detector Advantages

Answer 8

Almost all hydrocarbons are indicated, works well with GC column

Question 9

Flame Ionization Detector Disadvantages

Answer 9

Uses H gas, halons and freons may cause flame to go out, difficult to ignite in cold weather

Question 10

Photoionization Detector Application

Answer 10

Ionizable VOCs, most petroleum distillates heavier than C4

Question 11

Photoionization Detector Advantages

Answer 11

Easy to use, sensitive to wide range of compounds, works well with GC column

Question 12

Photoionization Detector Disadvantages

Answer 12

Sensitive to humidity, not usable in humid conditions, not sensitive to several significant toxic gases

Question 13

Electron Capture Detector (ECD) Application

Answer 13

Electrophilic compounds, halogenated compounds

Question 14

Electron Capture Detector (ECD) Advantages

Answer 14

Extremely sensitive to halogen-containing compounds, works well to GC column

Question 15

Electron Capture Detector (ECD) Disadvantages

Answer 15

Responds to O2 in air thus requiring GC to separate compounds of interest

Question 16

Electrochemical Application

Answer 16

Chemically active compounds and elements

Question 17

Electrochemical Advantages

Answer 17

Selective response, low zero drift

Question 18

Electrochemical Disadvantages

Answer 18

Habituation, cell can be poisoned by certain acid gases

Question 19

Non-dispersive Infrared Application

Answer 19

Specific gases e.g. CO, O2

Question 20

Non-dispersive Infrared Advantages

Answer 20

Highly specific, easy to use

Question 21

Non-dispersive Infrared Disadvantages

Answer 21

Interference from other gases

Question 22

FTIR Application

Answer 22

Specific gases and vapors

Question 23

FTIR Advantages

Answer 23

Highly specific, extremely sensitive

Question 24

FTIR Disadvantages

Answer 24

High cost, power consumption

Question 25

UV Absorption Application

Answer 25

Specific gases and vapors

Question 26

UV Absorption Advantages

Answer 26

Good sensitivity

Question 27

UV Absorption Disadvantages

Answer 27

Interference from particulates, other gases and vapors

Question 28

Metal Film Absorption Application

Answer 28

Gold film for Hg vapor

Question 29

Metal Film Absorption Advantages

Answer 29

High specificity

Question 30

Metal Film Absorption Disadvantages

Answer 30

Discontinuous sampling/time between sampling

Question 31

Colorimetric Detector Tubes Application

Answer 31

Qualitative/Quantitative measurement of specific airborne contaminants

Question 32

Colorimetric Detector Tubes Advantages

Answer 32

Cheap, wide range of application

Question 33

Colorimetric Detector Tubes Disadvantages

Answer 33

Depends on specific tube, hand powered pump