| Technique |
Example Instrument/Method |
Positive Features |
Negative Features |
| Analytical (Screening) Methods |
|
| Direct-measuring |
Organic vapor analyzer |
- On-site detection and quantification - Capability of catching concentration excursions |
- Low sensitivity - Low specificity |
| |
Photo-ionization detector |
| Field/Analytical |
Portable gas chromatograph |
- On-site detection and quantification - Allows use of simple collection device such as a Tedlar bag - Better detection capability than the direct-measuring techniques |
- Usually considered a “screening” method because does not involve identification using a mass spectrometer |
| |
|
| Collection Methods |
|
| |
Evacuated canisters |
- Capability of taking multiple aliquots for analysis |
- More expensive than adsorbent tube method - May require special handling to prevent sample deterioration during transport to lab for analysis |
| |
Adsorbent media tubes |
- Less expensive than evacuated canister method |
- May be subject to “breakthrough” problems - May require special handling to prevent sample deterioration during transport to lab for analysis |
| |
Passive badge sampler |
- Can monitor longer-term period of time - Relatively inexpensive |
- Higher humidity can produce erroneous results - Possible back- diffusion off sampling medium - Possible interferences between compounds |
