Conversion of Agilent EI GC/MSD Systems From Helium To Hydrogen Carrier Gas

1. Conversion of Agilent EI GC/MSD Systems From Helium To Hydrogen Carrier Gas Bruce D. Quimby, Ph.D. GPD Solutions Group and Harry F. Prest, Ph.D. GC/MS Research and Development October 9, 2012 C&EN Webinar

2. Question: Have You Ever Tried Converting Your GC/MS From Helium To Hydrogen Carrier Gas? C&EN Webinar Answer 1: “No. Never thought of trying it. Too busy.” Answer 2: “We did that several years ago. It took some effort, but it has been working fine.” Answer 3: “We tried it once. The results were horrible and confusing! We had a very high background, high noise, and very bad peak shapes. After 4 days, we went back to helium.”

3. Introduction: Converting from He to H2 Carrier Gas C&EN Webinar Many GC/MS users are considering changing from helium to hydrogen carrier gas due to price/availability problems with helium. • Read Chemical and Engineering News - July 16, 2012 (Page 32-34) This talk describes the steps recommended for converting EI GC/MS methods. It is important to recognize the differences with using hydrogen carrier. Time should be allotted for adapting the method, optimization, and resolving potential problems. Areas that will need attention include: • choice of supply of H2 • remove/bypass carrier gas filter (may be re-installed later if needed) • GC/MSD hardware changes • choosing new chromatographic conditions • potential reduction in signal-to-noise ratio (2-5x) • changes in spectra and abundance ratios for some compounds • activity and reactivity with some analytes

4. Introduction: Converting from He to H2 Carrier Gas C&EN Webinar Methods that will generally require less optimization include analytes that are: • “durable” compounds • at higher concentrations • analyzed with split injections • derivatized Methods that will generally require more optimization include analytes that are: • “fragile” compounds • at trace concentrations Allow time for necessary updates to SOPs and validation

5. H2 Safety C&EN Webinar

6. Letter from Agilent Safety Engineer: Describes H2 Safety Features of Agilent GCs C&EN Webinar

7. Designed for Reliability – H2 Safety Safety Shutdown When gas pressure set points are not met, the valve and heater are shut off to prevent explosion Flow Limiting Frit If valve fails in open position, inlet frit limits the flow Oven ON/OFF Sequence Fan purges the oven before turning on heater to remove any collected H2 Explosion Test GC and MS designed to contain parts in case of explosion C&EN Webinar

8. Safety First: Read This Before You StartG3170-90010 C&EN Webinar

9. Source of H2 Carrier and Plumbing C&EN Webinar

10. Source of Hydrogen: Use a Hydrogen Generator C&EN Webinar Higher initial expense than cylinders, much lower cost over time Very clean H2, >99.9999% available More consistent purity Safety considerations • H2 is only generated at needed pressure (like 40 psig) • Flow is limited (like 250 mL/min) • Auto-shutdown if set point pressure cannot be maintained • Minimal stored gas (like 50 mL at 40 psig) of H2 at any one time Make sure to buy a good one with a low spec for water and oxygen

11. Hydrogen Generation This is an example of the type of generator to use for H2carrier gas. Look for generators with a >99.9999% specification and low individual specs on water and oxygen. C&EN Webinar

12. Plumbing the Instrument C&EN Webinar Chromatographic qualitystainless steel tubing is often recommended for H2 plumbing and is probably the best choice if available. Users may have to follow local codes or internal company guidelines. We have also used new 1/8th copper that has been cleaned for GC use. Dirty tubing will cause huge contamination problems, as H2 appears to carry dirt out of metal more than He does. Don’t use really old copper tubing, as it becomes brittle and can break. Note that MSD leak checks will not always find big outgoing leaks. Leak check when complete with electronic leak detector. When plumbing a H2 generator, start out with no traps. Only add traps if needed. Make sure the water and oxygen levels are low enough.

13. Split Vent and Septum Purge Vent Should be Connected to Exhaust C&EN Webinar

14. MS Components Required for Conversion: Magnet and Draw Out Lens C&EN Webinar

15. Check the Magnet in the 5975 If the magnet in the 5975 does NOT have a serial number along the left edge (as viewed through the source window), it is suitable for use with Helium, but not Hydrogen. If not, please contact your Agilent service engineer to change it to a Helium and Hydrogen compatible magnet before converting the system to H2 carrier. Note: All 5973 magnets are compatible with both He and H2 C&EN Webinar

16. Replace the Standard 3 mm Draw Out Lens With the Optional Hydrogen Draw Out Lens G2589-20045 Hydrogen Draw Out Plate, Inert Standard 3 mm Draw Out Plate, Inert C&EN Webinar

17. Choosing a Column and Method Conditions C&EN Webinar

18. MSD Pumping Capacity for H2 is Less than for HeThis Limits Column Choice C&EN Webinar These are approximate values for the 5975. Maximum flow of H2 to maintain reasonable source pressure: • Performance turbo: 2 mL/min • Standard turbo: 1 mL/min • Diffusion pump: 0.75 mL/min • Pressure pulsing: turbo < 3 mL/min, diffusion < 2.5 mL/min It is very helpful to have an ion gauge on the MS to monitor the vacuum vs. column flow. Try to avoid flows that produce pressures higher than 5 x 10-5 torr. You can get useful data above this pressure, but performance may start to degrade

19. Guidelines for Choosing Column Dimensions and Flows for Method Converted from He to H2 C&EN Webinar Determine max flow of H2 into MS that will give source pressure of 5 x 10-5 torr or less source pressure. This is your max column flow. Choose column dimensions at initial oven temp of method to give: • a flow < max column flow for vacuum pump • a flow > min column flow for efficiency • an inlet pressure of at least 5 psig Keeping a temperature ramp of the same number of °C/void time will give similar elution order. Use the Agilent method translator for this. These are only approximate guidelines. Sometimes you may have to deviate from them.

20. Van Deemter Curves If the flow of He or H2 is too low, you loose efficiency MUCH FASTER than if it is too high. This is why operating at or above minimum linear velocity is important. Use 35 cm/sec as minimum for H2 C&EN Webinar

21. Column Choice C&EN Webinar When in doubt (or a hurry) use: • Use 20m x 180 um column and set constant flow at 0.3-0.5 mL/min. • Try to get a linear velocity of at least 35 cm/sec Try to use the same phase and phase ratio to get similar elution order. Smaller bore columns have lower capacity. You may have overloading on high level calibration standards, or samples You may need to use pulsed injection to load sample into small bore columns when using a low flow rate. The flow range for your H2 setup is limited on the low side by the flow to get 35 cm/sec and on the high side by the vacuum pump capacity

22. Using the Agilent Flow Calculator: Set Linear Velocity to 35 for H2 Carrier If Inlet Pressure Too Low, Raise Flow Inlet pressure is too low Set inlet pressure to 5 psig C&EN Webinar

23. Using the Agilent Method Translator: 30m x 0.25 mm id x 0.25 um Checkout Column with Perf Turbo Meets flow requirements for pump and column efficiency with 2x speed gain C&EN Webinar

24. Using the Agilent Method Translator: With Perf Turbo and Std Turbo • For 20m x 0.18 mm id x 0.18 um Column: • Meets flow requirements for standard turbo pump. • Flow here is chosen to give a 2.5 x speed gain. C&EN Webinar

25. Initial Startup with Hydrogen C&EN Webinar

26. Initial Problems with Switching GC/MS Methods to from He to H2 Carrier Gas • High background that looks like hydrocarbons  • Reduced signal to noise (worse MDL)  • Significant tailing for many compounds  C&EN Webinar

27. Switch to H2 1st Problem: High Background • You will see this throughout work with H2. • It will get much smaller with time and use. • It used to takes days or weeks for background to fall to acceptable levels. Agilent developed a new conditioning protocol to clean-up the background much faster. (see later slide) C&EN Webinar

28. 1 Amphetamine Lorazepam 15 2 Phentermine 16 Diazepam 3 Methamphetamine 17 Hydrocodone 4 Nicotine Tetrahydrocannabinol 18 5 Methylenedioxyamphetamine(MDA) 19 Oxycodone 6 Methylenedioxymethamphetamine(MDMA) 20 Temazepam 21 Flunitrazepam 7 Methylenedioxyethylamphetamine 22 Diacetylmorphine 8 Meperidine 23 Nitrazepam 9 Phencyclidine 24 Clonazepam 10 Methadone 25 Alprazolam 11 Cocaine 26 Verapamil 12 SKF-525a (RTL Compound) 27 Strychnine 13 Oxazepam 28 Trazodone 14 Codeine GC/MS Toxicology Analyzer Checkout Sample 5 ng/uL each compound 9 17 16 8 10 12 4 11 7 22 18 3 15 2 25 21 27 6 26 14 20 1 24 28 19 23 18 2 4 6 8 10 12 14 16 13 5 C&EN Webinar

29. Switch to H2 2nd Problem – Peak Tailing Abundance Abundance 3000000 2800000 2000000 2600000 1800000 2400000 1600000 2200000 1400000 2000000 1200000 1800000 1600000 1000000 1400000 800000 1200000 600000 1000000 400000 800000 200000 600000 400000 0 Time--> 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 200000 0 Time--> 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20m x 0.18mm id x 0.18 um DB-5MSUI Hydrogen Helium Immediately after conversion to H2, peak shapes on TIC are poor and tailing badly. C&EN Webinar

30. Switch to H2 3rd Problem: Spectrum Changes over Peak Profile Abundance Abundance Average of 8.018 to 8.036 min.: ToxCKO_H2_4.D\data.ms Average of 8.048 to 8.085 min.: ToxCKO_H2_4.D\data.ms 24000 82 91 182 22000 14000 20000 12000 18000 16000 10000 14000 8000 12000 42 10000 78 6000 105 8000 41 64 4000 6000 55 4000 115 2000 68 167 128 303 198 122 141 207 2000 167 152 272 191 221 154 281 242 300 265 341 327 314 135 215 0 244 230 259 341 288 327 0 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 m/z--> m/z--> There is More Happening Here than Simple Peak Tailing Cocaine 7.20 7.40 7.60 7.80 8.00 8.20 8.40 8.60 8.80 9.00 Peak Spectrum Tail Spectrum Cocaine Not Cocaine C&EN Webinar

31. Main Ions of Cocaine Do Not Tail. Tail Made Up of Other Ions Tail is different than peak. May be formed from catalytically shredded main component. This problem is reduced with time Cocaine Tail is not cocaine ions C&EN Webinar

32. H2 Conversion Considerations for Success C&EN Webinar

33. Agilent’s Recipe for H2 Success: Minimizing the Time for Chromatography and Background to Stabilize • Have a good source of clean hydrogen like a >99.9999% purity hydrogen generator. • Keep H2 flow limited to value suitable for your pumping system • Use optional Hydrogen draw out lens • After setup, purging and pump down: • Set the source to max temp for your source (check to see what yours is) • Reduce the EMV to 800V • Leave the FILAMENT ON overnight. This cleans up background rapidly. • Peak shape will be much better and background will be much lower in the morning. • Lower the source temp to method value, retune, and run some samples • It is a good idea to have an extra set of filaments on hand in case one burns out. This hasn’t been a problem, but a good idea. C&EN Webinar

34. Abundance 2600000 2400000 2200000 2000000 1800000 1600000 1400000 1200000 1000000 800000 600000 400000 200000 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 Time--> Agilent’s Recipe for H2: Success • Peak Shape Much Better • Background is Lower • Better Signal-to-Noise C&EN Webinar

35. Agilent Toxicology Analyzer • Features: • Configured, tuned and tested for the application • Retention time locked (RTL) with DRS database • Constant flow to MS • Backflush to reduce cycle time and remove matrix artifact • Challenge: • Convert from He to H2carrier without altering performance criteria C&EN Webinar

36. AUX EPC He Constant Flow Toxicology Analyzer • Parameters: • Constant Flow to MS • RTL DRS Method Liquid Injector Vent S/S Inlet ~12psi 1m x 0.15 mm id 1.7 mL/min Column PUU 5975C MSD 7890A GC 15 m X 0.25 mm id X 0.25 um DB-5MSUI C&EN Webinar

37. AUX EPC H2 Constant Flow Toxicology Analyzer • Parameters: • Constant Flow to MS • RTL DRS Method Liquid Injector No Change in Performance Vent S/S Inlet ~8psi 0.81m x 0.12 mm id 1.7 mL/min Column PUU 5975C MSD 7890A GC 15 m X 0.25 mm id X 0.25 um DB-5MSUI C&EN Webinar

38. Abundance 1200000 1000000 800000 600000 400000 200000 0 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 Time--> Abundance 1200000 1000000 800000 600000 400000 200000 0 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 Time--> Converting Toxicology Analyzer from He to H2 Toxicology Check Out Mix Helium Hydrogen C&EN Webinar

39. Switching GC/MS Methods to from He to H2 Carrier Gas • Reduced high background that looks like hydrocarbons  • Improved signal-to-noise relative to pre-conditioned state  • Reduced tailing for many compounds  C&EN Webinar

40. Performance Expectations C&EN Webinar

41. Performance Expectations C&EN Webinar Signal-to-noise ratio is often worse by about 2-5 x. This obviously varies from compound to compound While most spectra remain same, there are always exceptions. Users should check the reference spectra for important targets to make sure they have not changed Same comment for target/qualifier ratios Some compounds may disappear at low levels.Examples include: some nitrogen and oxygen containing compounds (alcohols, aldehydes, ketones) like those found in flavor samples

42. Library Match Factors – Helium and Hydrogen Carrier Gas Comparison NIST (Forward) NIST (Reverse) Helium Hydrogen Helium Hydrogen Dichlorvos 924 867 929 904 Mevinphos 925 852 973 967 Ethalfluralin 927 897 927 897 Trifluralin 897 856 897 857 Atrazine 914 901 915 908 BHC-gamma (Lindane, gamma HCH) 925 858 931 878 Chlorpyrifos-methyl 922 897 926 908 Heptachlor 926 851 929 856 Malathion 916 836 953 846 Chlorpyrifos 901 890 902 892 DDE, p,p'- 934 903 946 940 Dieldrin 926 903 927 903 Hexazinone 901 832 906 912 Propargite 851 821 857 829 Leptophos 884 847 884 847 Mirex 903 881 914 934 Fenarimol 905 872 908 877 Coumaphos 864 804 870 813 Etofenprox (Ethofenprox) 906 842 916 843 In general, these 20 spectra in hydrogen carrier show lower match factors than in helium carrier gas. They can still be properly identified in library search. C&EN Webinar

43. Lindane • Observations • Ion ratios changed • Extra peaks in H2 Helium Carrier Gas NIST Forward Match = 925 Hydrogen Carrier Gas NIST Forward Match = 858 C&EN Webinar

44. Heptachlor • Observations • Ion ratios changed Helium Carrier Gas NIST Forward Match = 926 Hydrogen Carrier Gas NIST Forward Match = 851 C&EN Webinar

45. Other Considerations: C&EN Webinar • H2 is not an inert gas, and therefore inertness problems will still exist or be worse. Use the lowest inlet temp that works (to reduce reactions with H2) Use pulsed injection, especially with small bore columns Consider using an MMI in cold splitless mode for fragile compounds Using a deactivated S/SL weldments might help (but don’t ever scrub it) Avoid using methylene chloride as a solvent (especially wet). • At higher inlet temps (like >280C), HCl is formed and causes problems. • If must be used, use lowest inlet temp and maybe a deactivated S/SL weldment, or Multimode inlet Avoid carbon disulfide as a solvent Use liners with a taper at bottom to minimize sample contact with gold seal • Use Agilent Ultra Inert Liners.

46. Hydrogen Carrier Summary C&EN Webinar Get a GOOD hydrogen generator and plumb it properly Pick a column that meets the flow needs of method and MSD pump Do magnet update (if necessary) and install Hydrogen draw out lens After purging and pump down, set source to max temp and EM to 800V. Leave filaments on all night. Reset source temp, retune, and run samples. Run practice samples for a few days to make sure system has stabilized Source cleaning will be needed much less frequently

47. Thank You for Your Attention For additional information please visit: http://www.agilent.com/chem/heliumupdate C&EN Webinar