GC Large Volume Injection Optimization - US EPA

1 Large Volume InjectionPresented ByTim AndersonGC Product ManagerPhenomenexEPA Region 6 QA ConferenceOctober, 2015 GoalDevelop a method to use the least amount of sample and achieve the highest possible s/n response2 Typical L Splitless500 g soilS/N = 25 Larger L Splitless500 g soilS/N = 125 Larger Injection / Smaller L Splitless100 g soilS/N = 25 What to Watch Out For! L Dichloromethane @ 250 C & 14 psi = 336 LLiner Volume 990 L = 1008 L; exceeds liner Volume ! Flashback Ghost peaks Loss in sensitivity / linearity3 PreliminaryAssumptions Pressure Pulsed Injection tend to improve analyte responses Improves transfer of analytes from the inlet into the column Started with Pressure Pulse and tested this assumption during throughout the experimentAnalytes: Started with a relatively simple list of Polycyclic Aromatic Hydrocarbons (PAHs) Contains relatively wide range of retention times Subsequent work includes other compounds4 Column.

2 Zebron ZB-SemiVolatiles30 m x mm x mColumn mL/min Helium (constant flow)Oven Program:100 C for to 260 C @ 30 C/min to 295 C @ 6 C/min to 325 C @ 25 C/min for 2 minInlet Liner:Direct Connect Liner with top taper and bottom holeInjection:Pressure Pulse @ 30 psi for min, splitlessfor minDetector: MSD; 46-450 amu, transfer line = 320 CInitial 1e+07 +07 +07 +07 Time-->Abundanc eTIC: ExperimentsWhat is the best liner?Different stylesCompared early, mid, and late eluters6 Liner PerformanceDirectConnectDual Taper, bottom hole Maximum Injection Volume = 10 L Maximum intensity = Better response for higher MW Response decreases after 10 L!

3 + + + + + + Volume (uL)FluoreneChryseneBenzo[g,h,i]perylene 7 DirectConnectTop Hole Maximum Injection Volume = L+ intensity = Better response for lower + + + + + Volume (uL)FluoreneChryseneBenzo[g,h,i]perylene Liner PerformanceSingle Taper With Wool Maximum Injection Volume = 10 L Maximum intensity = Consistent response, except at larger volumes which benefit lower MW Response decreases after 10 L! + + + + + + + + Volume (uL)FluoreneChryseneBenzo[g,h,i]perylene 8 Cup Liner Maximum Injection Volume = L Maximum intensity = Slightly better response for higher MW Response decreases after + + + + + + + Volume (uL)FluoreneChryseneBenzo[g,h,i]perylene Liner PerformanceFocusLiner(single taper with wool in middle)

4 Maximum Injection Volume = L Maximum intensity = Much better response for lower MW Possible cooling of glass + + + + + + + + + VolumeFluorenechryseneBenzo[g,h,i]peryle neAverage Liner + + + + + + +0702468101214 Direct ConnectBottom Hole dualtaperDirect Connect TopHoleCup LinerSingle Taper WoolBotomFocusliner10 Single Taper with Wool at bottom provides highest response at L Injection , bis(2-ethylhexyl) Activity11 Relative Responses1-taperWool-middleWool-bottomst raightCupWool-bottom . 0 07 . 5 08 . 0 08 . 5 09 . 0 09 . 5 01 0 . 0 0200004000060000800001000001200001400001 6000018000020000022000024000026000028000 0300000320000340000360000380000T im e - - >A b u n d a n c eT I C : A G 8 4 9 9 _ 2.

5 D7 . 0 07 . 5 08 . 0 08 . 5 09 . 0 09 . 5 01 0 . 0 05 0 0 0 01 0 0 0 0 01 5 0 0 0 02 0 0 0 0 02 5 0 0 0 03 0 0 0 0 03 5 0 0 0 04 0 0 0 0 04 5 0 0 0 05 0 0 0 0 05 5 0 0 0 0T im e -->A b u n d a n c eT I C : A G 4 6 5 7 _ 2 . DNormal LinerCompeting Liner12345671257 Inlet Temperature = 275 CRatio of over middle PAH Benzo(g,h,i)perylene/ PyreneInlet Discrimination: Reduced response of later eluting compounds due to their lower volatility at a given temperature. Higher Inlet Temperatures = Greater Response for Late Eluting CompoundsInjection Peak Intensity (Benzi[g,h,i]Perylene / Pyrene)Inlet TemperaturePAH Response vs.

6 Inlet Temperature12 Active Analytes vs. Temperature13 Kinetics states that reactions occur faster at higher temperatures Expected less relative response at higher temperatures Liner was new and CLEAN!Note: Conditions were for Pulsed Split Injection parameters; inlet liner with wool at Resopnse to DFTPPI nlet TemperatureRelative Analyte Resopnse vs. Inlet TemperaturePCP RatioBenzidine RatioDDT Ratio60 C gave much better initial peak shapeInitial peak shape still not perfectNaphthalene at min, last PAH at minBenzo[b]fluoranthene / Benzo[k]fluoranthene = valley height (8270D requirement = 50%)Indeno[1,2,3-cd]pyrene/ Dibenz[a,h]anthracene = >Abundanc eTIC: ime-->Abundanc eT IC: PAH.

7 4 04 . 5 04 . 6 04 . 7 04 . 8 04 . 9 05 . 0 05 . 1 05 . 2 05 . 3 005 0 0 0 0 01 0 0 0 0 0 01 5 0 0 0 0 02 0 0 0 0 0 02 5 0 0 0 0 03 0 0 0 0 0 03 5 0 0 0 0 04 0 0 0 0 0 04 5 0 0 0 0 05 0 0 0 0 0 05 5 0 0 0 0 0T im e -->A b u n d a n c eT I C : P A H 0 0 6 . DT I C : P A H 0 0 5 . DNo GuardGuardConfirmation of Pressure Pulse 3 .0 04 .0 05 .0 06 .0 07 .0 08 .0 09 .0 01 0 .0 01 1 .0 01 2 .0 01 3 .0 01 4 .0 01 5 .0 0050000010000001500000200000025000003000 00035000004000000T im e -->A b u n d a n c eT IC : L V I0 0 3 .DT IC : L V I0 0 4 .DPressure Pulse (30 )No pressure pulseBenzo[b]fluoranthene82% [k]fluoranthene81% [a]pyrene83% [1,2,3-cd]pyrene88% [a,h]anthracene86% [g,h,i]perylene85% of Pressure PulseHigher pressures decreased initial responses Lower pressures decreased all signals less transfer on-columnOptimum was found to be 30 psi Decreasing pressure time at 40 psi did NOT bring back ime-->Abundanc eT IC: PAH ime-->Abundanc eT IC: PAH ime-->Abundanc eT IC: PAH psi30 psi40 ime-->Abundanc eT IC: PAH IC: PAH IC.

8 PAH psi40 psi30 psiOptimization of Pressure PulseZoom in on Benz[a]anthracene and Chyrsene18 Expected that standard splitlessinjection might allow for longer splitlesshold times to improve responseLonger splitlesshold times gave better responses, but not comparable to the pulsed splitlessinjectionNon-Pulsed Consideration19 1 1 . 6 01 1 . 7 01 1 . 8 01 1 . 9 01 2 . 0 01 2 . 1 01 2 . 2 01 2 . 3 01 2 . 4 01 2 . 5 01 2 . 6 01 2 . 7 0020000040000060000080000010000001200000 1400000160000018000002000000220000024000 0026000002800000T i m e - - >A b u n d a n c eT I C : L V I 0 0 3.

9 DT I C : 0 5 1 1 1 2 - M 0 1 . DT I C : L V I 0 0 4 . DT I C : L V I 0 0 6 . DLater Eluting PAH sPulsed Splitless for minSplitless for minSplitless for minSplitless for min(5m x ID guard)(5m x ID guard)(1m x ID guard)Larger ID Guard: mm ID20 Later peaks NOT taller; did not increase loading of any peaksLost early elutersPulsed vs. Non-pulsed mm ID Guard21 Non-pulseImprovedEarly ElutersPressure Pulse No pressure pulseNon-pulseReducedLater ElutersHoped that improved efficiency would give higher responseRetention times were earlier with last PAH before 14 minutesAll responses were lower, especially late eluting PAHsExperimented with flow rates, pressure pulses, and Injection volumesSmaller ID ime-->Abundanc eT IC: IC: ime-->Abundanc eT IC: PAH Dimension: Zebron ZB-SemiVolatiles30 m + 5 m Guard x mm ID x mColumn mL/min Helium (constant flow)Oven Program.

10 60 C for to 260 C @ 30 C/min to 295 C @ 6 C/min to 325 C @ 25 C/min for 2 minInlet Liner:Single Taper with wool at bottom L Pulsed Splitless, Pressure Pulse @ 30 psi for min, splitlessfor minDetector: MSD; 46-450amu, transfer line = 320 CAnalytes:PAHs at 5 ppm in dichloromethaneFinal Conditions for PAHs234 . 0 05 . 0 06 . 0 07 . 0 08 . 0 09 . 0 01 0 . 0 01 1 . 0 01 2 . 0 01 3 . 0 01 4 . 0 01 5 . 0 01 6 . 0 01 7 . 0 02 0 0 0 0 04 0 0 0 0 06 0 0 0 0 08 0 0 0 0 01 0 0 0 0 0 01 2 0 0 0 0 01 4 0 0 0 0 01 6 0 0 0 0 01 8 0 0 0 0 02 0 0 0 0 0 02 2 0 0 0 0 02 4 0 0 0 0 02 6 0 0 0 0 02 8 0 0 0 0 03 0 0 0 0 0 03 2 0 0 0 0 03 4 0 0 0 0 03 6 0 0 0 0 03 8 0 0 0 0 04 0 0 0 0 0 04 2 0 0 0 0 04 4 0 0 0 0 04 6 0 0 0 0 04 8 0 0 0 0 05 0 0 0 0 0 05 2 0 0 0 0 0T im e -- >A b u n d a n c eT I C : L V I B 0 0 7.