POPULAR CONFIGURATION GCs
Multiple Gas Analyzer #1
General Operating Procedures
1. Set thecylinderheadpressure15-20psihigher than the
headpressure. Thecarrierheadpressureused togenerate
the testchromatogramsat thefactory isprintedon theright
sideofyourGC.
2.
IMPORTANT:
Damageordestructionof theTCDfilamentswilloccur ifcurrent isapplied in theabsence
of flowingcarriergas. ALWAYSverify thatcarriergascanbedetectedexiting theTCDcarriergasoutlet
BEFORE turning theTCDcurrentON. Tagged for identification, theTCDoutlet tubing is located in the
columnoven. Theendof this tubingwillbeprotrudingfrom thecolumnovenwallon thedetectorside,unless
there isalsoanFIDorHID installed. In thiscase, theTCDoutlet tubingwillbeconnected to theFIDorHID
detectorbulkheadfitting in thecolumnovenwall. Place theendof theTCDoutlet tubing insome liquidand
observe. If therearenobubblesexiting the tube, there isaflowproblem. DONOT turnON theTCDcurrent
ifcarriergasflowisnotdetectable. Afilamentprotection
circuit shutsOFF theTCDcurrent if thecolumnhead
pressuredropsbelow3psi,but itcannotpreventfilament
damageunderallcircumstances. Any lackofcarriergas
flowshouldbecorrectedbeforeproceeding. Ifnecessary,
reconnect theTCDoutlet tubing to theFIDorHIDwhen
youarefinished testing thecarrierflow.
4. Set thevalveoven temperature to90
o
C. Ifpresent:set theFID/Methanizer temperature to380
o
C;set the
HID temperature to200
o
C.
TheTCDcarrier outlet tubing is
tagged inside thecolumnoven.
Unlessconnected toanotherdetector,
theendof theTCDoutlet tubingwillbe
on theoutsideof thecolumnovenwall.
For thisparticularTCD-equippedMG#1, thehead
pressure required fora20mL/min flow is29psi.
3.IfyourMG#1hasanFID/Methanizer,set theFIDhydrogen
flow to25mL/minute,and theFIDcombustionair to250mL/
minute. IfyourMG#1hasanHID, set theheliummake-up
flow to40mL/minuteand theheliumcarrier to10mL/minute.
Again,check the“GASFLOWRATES”printedon theright-
handsideofyourGCforitsflowsandtheapproximaterequired
pressures. Gasflowsareadjustedusing the trimpotson the top
edgeofyourGC’sfrontcontrolpanel. Turneachtrimpotwhile
pressing itsLOCALSETPOINTbuttonuntil theLEDdisplay
shows the samepressure (inpsi) as that printedunderGAS
FLOWRATES.
