DETector Engineering
&
Technology, inc.
486 N.Wiget Lane,Walnut Creek,CA94598USA
telephone: (925) 937-4203
fax: (925) 937-7581
DET
e-mail:
innovations inchemicaldetection
THERMO SCIENTIFIC TRACEGC - DET retrofit hardware consists of an NPDITID/FID tower assembly and
ceramic tipped jet that mount easily onto the Thermo detector base. In contrast to Thermo's NPD hardware
structure, theDET retrofit provides apreferred concentriccylindergeometry for the ion sourceand collector, and
provides aneasy top access for self-aligningmounting of the ion source. Ion sources used with the DET retrofit
are identical to those used with Agilent
689017890
equipment, and all DET ion source types are available for use
in NPD, TID, or FlOmodes. Thermo's NPD electronics currently are the best available with regard to providing
optimum response in all NPD and TID modes of detection, and the combination with DET retrofit hardware
provides easy conversion to many different types of selectivity and applications. In addition to an NPDITID/FID
tower, theThermobase can alsobe fitwithaRemoteFlOtowerwhich positions the ion sourceseveral centimeters
downstream of the jet so a flame can be ignited at the jet for additional Remote FlOand FTIDmodes of selective
detection. ATandem Towerconfiguration has also been fit onto the Thermo base so that 2simultaneous detector
signals can beobtained from the same GC effluent.
VARIAN/BRUKER TSD GC MODELS - Similar to the Thermo retrofit, a DET retrofit NPDITID/FID tower
assembly and ceramic tipped jet are designed to mount easily onto the Varian/Bruker detector base. In contrast
to the Varian/Bruker TSD hardware structure, the DET retrofit is about half as large, and provides a preferred
concentric cylindergeometry for the ion sourceand collector. It also provides aneasy topaccess for self-aligning
mountingof the ion source into the tower. Ion sources used with the DET retrofit are identical to those used with
Agilent
689017890
equipment, and all DET ion source types are available for use in NPD, TID, or FlOmodes. The
DEThardware is compatiblewith the Varian/BrukerTSDelectronicswhich works fine for NPdetection. However,
for detection modes other than NPD, a stand-alone DETCurrent Supply is recommended for powering the ion
sources inordertoachievea tenfold improvement in signal to noise. Like the Thermo retrofits, alternativeRemote
FlOand Tandem TID tower assemblies are available to provide additional modes of selective detection.
SRI INSTRUMENTS
GC
MODELS - Like the Thermoand Varian/Bruker retrofits, aDEThardware retrofit for
SRI GCmodels consists of an NPDITID/FID tower assembly and ceramic tipped jet that mount onto a heated
FID/NPD base on the SRI GC. As with other DET retrofits, the DET hardware provides an optimum concentric
cylindergeometry for stream-lined gas flowand efficient ion collection, and easy end mountingof the ion source.
If SRI's NPDelectronics are used to power the ion sources, then the ion source structures are identical to those
used on Agilent
689017890
GCmodels except there is no Twinex electrical connector attached. An alternative to
usingSRI's NPDelectronics is to substitute astand-alone DETCurrent Supply formore stable precision control
of ion source heat and polarization, and more user friendly adjustments. When the DET supply is used, then the
ion sources include the Twinexconnector and are identical to those used on Agilent equipment. SRI's NPDsignal
amplifier suffices for signal measurement, and their built-in Peak Simple data system provides data analysis
capabilitywhen coupled to a laptop or desktop computer. The combination of an SRI GCand DEThardwarewith
multiple choices of interchangeable ion sources provides a small portable system applicable to many different
types of chemical analyses.
HP
5890
MODEL - The FID/NPD base on an HP5890GC is the "Agilent" configuration described earlier. DET
retrofit hardware in this case consists of a Remote FlO tower assembly that positions the ion source several
centimeters downstream of the jet. In addition, the DET retrofit includes a wide bore jet that allows capillary
columns of0.53mmdiameteror less tobe inserted clear through the jet to a termination closer to the ion source.
This is the preferred configuration for NPD and TIDmodes of detection. For Remote FlO and FTIOmodes, the
column is pulled down flush with the top of the jet and a flame is ignited at that jet top. DEl's 5890 retrofit
hardware is not compatible with existing 5890 detector electronics, so a stand-alone DET Current Supply is
required, as well as a stand-alone electrometer such as a Keithley 6485 Picoammeter. The DET 5890 retrofit
combination ofhardwareand electronics provides the capability for easy interchangeamong all availablemodes
of NPD, TID, Remote FlO, and FTID selective detection. In addition, the stand-alone electronics can be used to
support selective detection with any stand-alone DET transducers.
