L6.13
GAS CHROMATOGRAPHY
Specific
Competency 5
|
Identify
detectors, including thermal conductivity, flame ionization, and electron
capture in terms of their use, detection limits, and special characteristics;
list advantages and disadvantages of each
The technician should understand
the ideal characteristics of a detector, including:
- Stable, reproducible, reliable
and easy to use.
- Linear response to analytes
over several orders of magnitude.
- Useful over a temperature range
from room temperature to at least 400 degrees C.
- Short response time that is
independent of flow rate.
- Similar response for all analytes
or a predictable and selective response toward one or more classes of analytes.
- Nondestructive
- Low background noise and ease
of operation
They should be able to identify
and explain the uses of common detectors for GC, as well as how these detectors
meet the ideal characteristics listed above. Common detectors include:
- Flame Ionization Detector (FID)
- Nitrogen Phosphorous Detector
(NPD)
- Electron Capture Detector (ECD)
- Thermal Conductivity Detector
(TCD)
- Flame Photometric Detector (FPD)
- Atomic Emission Detector (AED)
- Photoionization Detector (PID)
- Electrical Conductivity Detector
(ELCD)
- Mass Spectrometer (MS)
Given a specific analytical problem,
they should be able to identify the most useful detector or, given a limited
number of detectors, be able to determine which is most suitable for the analysis.