General Operating Procedures Continued
TheSRIdualtrapdesigngivesthePurge&Trapusermanyoptionstoeffectivelytrapandreleaseanalytes
fromaparticularadsorbent. Duetoitslowaffinityforwater,Tenax
TM
-GRisespeciallyusefulforthepurgingof
VOCsfromaqueoussamples,making itagoodgeneralpurpose trapforEPAstylepurgeand trap techniques.
TheCarbosieve
TM
packed trap isveryretentivefor lighthydrocarbons,butsince it tends toretainwaterand
smear theotherpeaks, itshouldonlybeusedwhenvinylchloride isamong the targetanalytes. This tendency
tosmearmaybe reducedbymanipulating thedesorption times for the two traps. If theCarbosieve
TM
trap
(TRAP2) isdesorbedwhile theTenax
TM
-GR trap(TRAP1) isstillcold, thecomponentswill refocuson the
Tenax
TM
-GR. TheTenax
TM
-GR trap is thenheated todesorball thecomponents,which results insharper
peakson thechromatogram. These twochromatogramsarefromanEPAstylepurgeand trapanalysis. The
first onewasmadeusingEpap&t1c.evt for one trap. Thepeak separation ismuchbetter on the second
chromatogram,whichwasmadeusingEpap&t2c.evt for two traps.
INJECTORS
Purge & Trap
UsingTwoTraps
Sample:VOA-CYLstandard
Method:5030P&T injection
Column:60mMXT-1
Temperature program:
Initial
Hold Ramp Final
35
o
C 25.00 0.00 35
o
C
DELCDgain:MED
DELCD temp:260
