Methods for Increased Sample Throughput with Dirty … Liner MoC[2].pdf · Methods for Increased Sample Throughput with Dirty Samples Alan D Broske, Limian Zhao, and William H. Wilson

Methods for Increased Sample

Throughput with Dirty Samples Alan D Broske, Limian Zhao,

and William H. Wilson

Agilent Technologies, Inc.

February 17, 2012 1

Introduction GC inlet liner impacts sample transfer to the GC column – Limit matrix deposition in selected areas of the liner – Matrix impurities decompose chemical deactivation – Matrix impurities reach the analytical column

Solution with liner design and deactivation that are unique for the type of injection – Efficient spreading of matrix impurities over liner surface – A more stable deactivation layer – Use well deactivated glass wool to trap impurities

Agilent’s Ultra Inert liner deactivation process significantly improves the efficiency and robustness of the glass liner and glass wool deactivation – Quantitative analysis of pesticides – Reduced matrix interference

February 17, 2012 2

Liners Used Inlet liners used in this evaluation include – Dimpled liner (2 mm ID) – Single taper (4 mm ID) – Single taper with wool (4 mm ID)

February 17, 2012 3

Dimple (Agilent p/n 5192-2296)

Single Taper (Agilent p/n 5192-2292)

Single Taper with Wool

(Agilent p/n 5192-2293)

Experimental Analysis of pesticides by GC/ECD Instrument conditions

– Agilent GC/ECD system, equipped with Agilent 7683B Autosampler – Inlet: S/SL inlet using splitless mode @ 250 °C, purge time at 0.75 min,1 μL injection

volume – Inlet liner: Ultra Inert single taper splitless liner (Agilent p/n 5190-2292) – Carrier: He, constant flow, 0.9 mL/min (31 cm/sec) – Column: HP-5ms UI, 15 m x 0.25 mm, 0.25 μm (Agilent p/n 19091S-431 UI) – Oven: 120 °C (1 min), 30 °C/min to 220 °C, 8 °C/min to 280 °C (1 min) – ECD: 280 °C, N makeup, constant column + makeup

Sample – Endin/DDT sample in MtBE

February 17, 2012 4

Experimental Analysis of pesticides by GC/MS/MS Instrument conditions – Source @ 300 °C, Quad (Q1 & Q2) @ 150 °C – Data acquisition:

Agilent 7890A/7000 GC/MS/MS system, equipped with Agilent 7693 Autosampler – Cold Injection:

MMI inlet, splitless @ 60 °C (0.1), 700 °C/min to C300 °C (19). – Hot Injection:

MMI inlet, splitless in pulsed splitless mode @ 280 °C, purge flow 50 mL/min at 1 min, pulsed pressure 36 psi for 1 min

– 1 μL injection volume – Inlet liner:

Cold: 2 mm Dimpled liner (Agilent p/n 5190-2296) Hot: Ultra Inert single taper splitless liner with wool (Agilent p/n 5190-2293)

– Carrier: Cold: He, 10.68 psi, constant flow Hot: He, constant pressure, RT locked with Chlopyrifosmethyl @ 8.298 min

February 17, 2012 5

Experimental Analysis of pesticides by GC/MS/MS (continued)

Instrument conditions – Analytical column: HP-5ms UI, 15 m x 0.25 mm, 0.25 μm (Agilent p/n 19091-431 UI) – Purged Ultimate Union (Agilent p/n G3182-61580) for backflushing – Restrictor: Inert Fused Silica tubing, 0.65 m x 0.15 mm (Agilent p/n 160-7625-5) – Oven profile:

Cold: 60 °C (1), 50 °C/min to 150 °C, then 16 °C/min to 200 °C, then 7 °C/min to 300 °C Hot: 100 °C (2 min), 50 °C/min to 150 °C, 6 °C/min to 200 °C at 16 °C/min to 280 °C (6 min)

– Postrun backflush: 2 min @ 280 °C, backflush pressure @ 75 psi, inlet pressure @ 1 psi during backflush

– MSD: Transfer line @ 280 °C MRM

February 17, 2012 6

Experimental Analysis of pesticides by GC/MS/MS (continued)

Sample – Representative and active pesticides, 5 ng/mL to 500 ng/mL six points calibration

standards, 50 ng/mL QC

Matrix Sample – Five different fruits and vegetables matrix mixture: flower, banana, strawberry, pear, and

lettuce – Blank matrices sample were extracted following QuEChERS AOAC method

(sample extraction and following dispersive-SPE clean up) – Agilent Bond Elut QuEChERS AOAC extraction (Agilent p/n 5982-5755) and dispersive

SPE kit for general fruits and vegetables (Agilent p/n 5982-5022)

February 17, 2012 7

Results and Discussion Ultra Inert liners are highly deactivated as evidenced by low endrin/DDT breakdown (Hot splitless/ECD)

February 17, 2012 8

Endrin breakdown results from active sites on liner. DDT breakdown comes from the metal inlet parts. Multiple injections can decompose the liner deactivation and increase breakdown.

Results and Discussion Summary of pesticide breakdown on Ultra Inert and competitive liners after multiple injections

February 17, 2012 9

Ultra Inert liners show low breakdown even after 100 injections demonstrating high deactivation stability. Some competitive

liners show high breakdown and short lifetime.

Endrin Breakdown (%) DDT Breakdown (%)

Injection 1

Injection 50

Injection 100

Injection 1

Injection 50

Injection 100

UI Lot 31 3.7 9.6 11.4 7.4 7.6 5.6

UI Lot 40 1.3 3.7 15.6 1.5 2.1 3.2

UI Lot 42 1.2 8.3 12.2 2.5 3.9 3.0

Vendor 2 11.4 15.5 33.8 3.1 3.9 5.2

Vendor 3 2.7 7.2 34.6 5.8 5.5 11.5

Results and Discussion Ultra Inert liners are highly deactivated as evidenced by high recoveries of pesticides (Hot splitless/MS/MS)

February 17, 2012 10

The liner to liner performance reproducibility was tested with replicates of six Ultra Inert liners with wool from three different pesticides applications.

Groups of 12 pesticides were selected as representative analytes.

MRM of 10 ng/mL pesticide sample

1. Methamidophos 2. Dichlorvos 3. Mevinphos 4. Acephate 5. ?-Phenylphenol 6. Omenthoate 7. Dimenthoate 8. Altrazine 9. Lindane 10. Diazinon 11. Chlorothalonil 12. Chloropyrifos methyl 13. Vinclozolin 14. Carbaryl 15. Tolclofos methyl 16. Dichlorfluanid 17. Aldrin 18. Malathion 19. Dichlorobenzophenone 20. Pirimiphos ethyl 21. Tolyfluanid 22. Procymidone 23. Endrin 24. Ethion 25. Endosulfan sulfate 26. DDT 27. Endrin ketone 28. Iprodione 29. Phosmet 30. Phosalone 31. Permethrin isomers 32. Coumaphos 33. Deltamethrin isomers

Results and Discussion

February 17, 2012 11

Excellent liner to liner reproducibility achieved by Agilent Ultra Inert liners with wool.

Pesticides (peak #)

Repeatability: RSD (%) for analytes’ RF values of 50 ng/mL standard injections

In reagent solvent In fruits and vegetables QuEChERS extract

Ultra Inert liners w/ wool by 100 injections (# liners = 5)

Ultra Inert liners w/ wool by 50 injections (# liners = 7)

Ultra Inert liners w/ wool by 100 injections (# liners = 7)

Helix liners by 50 injections (# liners = 3)

Methamidophos (1) 7.7 5.1 11.7 25.4

Acephate (4) 5.4 16.6 30.1 55.6

Omenthoate (6) 10.5 27.1 44.8 49.9

Chlorothalonil (11) 4.8 7.3 13.4 14.9

Chlorothalonil (11) 8.6 9.3 15.2 11.7

Carbaryl (14) 8.7 11.7 19.9 13.4

Dichlorfluanid (16) 5.3 6.3 11.8 3.9

Tolylfluanid (21) 7.3 7.3 13.4 5.7

Endrin (23) 6.6 3.2 6.0 2.7

Endosulfan sulfate (25) 7.7 9.5 14.1 10.5

DDT (26) 6.3 23.1 36.4 16.8

Endrin ketone (27) 7.3 9.3 14.2 9.4

Iprodione (28) 5.1 5.0 8.1 20.3

Phosmet (29) 6.9 15.4 27.2 16.3

Results and Discussion Ultra Inert liners with wool generate higher responses for active compounds

February 17, 2012 12

Dimpled liners are highly deactivated as evidenced by high recoveries of pesticides with more uniform sample spreading (Cold splitless/MS/MS).

Pesticides Agilent Ultra Inert liner with wool Helix liner

Methamidophos

Acephate

Omenthoate

Dimenthoate

Results and Discussion (continued)

February 17, 2012 13

The inner diameter was reduced and flow path obstructed preventing matrix from reaching column. Sample directed to liner wall for more uniform

spreading and longer lifetime.

50 Matrix Runs

100 Matrix Runs

Results and Discussion (continued)

February 17, 2012 14

Calculated RSD for response factors of selected pesticides at 50 ppb. Performance goal is < 20%. Multiple liner lots shown (red is Helix liner).

Conclusion

The Ultra Inert deactivation shows high stability and provides long lifetime – Superior linearity for active pesticides with matrix impurities

– Consistent liner to liner (lot to lot) reproducibility

– Unique liner designs for temperature sensitive compounds with extended lifetimes

– Equivalent or superior to other equivalent liners or popular liners used in the demonstrated applications

February 17, 2012 15