- Hewlett-Packard Reference Manual

124
Detector Systems
This chapter provides information for the five HP 5890 SERIES II
(hereafter referred to as HP 5890) detector systems:
Flame Ionization Detector (FID)
Nitrogen•PhosphorusDetector (NPD)
Electron Capture Detector (ECD)
Thermal Conductivity Detector (TCD)
Flame Photometric Detector (FPD)
Capillary makeup gas flow rate
Detectors are designed to operate best with a carrier flow rate of at least
20 ml/min, typical of packed column applications. Carrier flow rates less
than about 10 ml/min (typically capillary applications) require capillary
makeup gas to ensure a total flow rate (carrier + makeup) of at least
20 ml/min. The TCD is an exception, requiring a total flow rate of only
5 ml/min.
For theFID, NPD,and TCD, HP Series530
capillary columns may be
used without capillary makeup gas, as long as carrier flow rate is between
10 and 20 ml/min. Some loss of detector sensitivity may occur at lower
flow rates.
For the ECD, capillary makeup gas should be used even with HP Series
530
capillary columns, because the large cell size requires high total
flow rate (at least 25 ml/min).
Makeup gas is added directly to H
for an FID or NPD within the
detector flow manifold; for an ECD or TCD, it is added into the column
effluent stream via a capillary makeup gas adapter fitted into the
detector column inlet.