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 the FID, NPD, and TCD, HP Series 530 ¿ 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.
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