From Helium to Hydrogen: GC-MS Case Study on SVOC s in Water

Transcription

1 From Helium to Hydrogen: GC-MS Case Study on SVOC s in Water Dwain Cardona Senior Applications Scientist Thermo Fisher Scientific 1 The world leader in serving science

2 N 2 from Generator H 2 from Generator H 2 f r o m C y l i n d e r UHP He from Cylinder Helium and Profitability of Drinking Water Testing Labs 2

3 Helium to Hydrogen Migration: Practicalities Hydrogen Carrier Gas: Van Deemter Curve Thermo Scientific Position Hydrogen Safety Points Cylinders vs. Generators GC-MS Tuning Baking & HC Background Water Spectrum Check Resolution Assurance Target Tuning (DFTPP & BFBs) GC Inlet and Column Maintenance Mode of Injection Liner Selection Column Selection Performance: U.S. EPA Methods 524 & 525 Linearity (measuring accuracy) Sensitivity (MDLs) Spectral Integrity Ion Ratio Stability Before you migrate to hydrogen carrier gas on your GC-MS 3

4 Carrier Gases: Physical Properties Property He H 2 N 2 Ar Molecular Mass, Da Density, kg/m Diffusion Coefficient, cm 2 /s Viscosity, Pa s u opt, cm/s <1 He H 2 Carrier Gas Density: Less is Better Diffusion Coefficient: More is Better** Dynamic Viscosity : Less is Better He H 2 * 4 * Crystal Lattice Density Analogy only, O.Fryazinov; A.Pasko; V.Adzhiev Computer-Aided Design 211, 43(3) ** On the RHS of the van Demmter curve, that is.

5 5 Dynamic Viscosity vs. Temperature

6 6 Carrier Gases Efficiencies: Van Deemter Plots

7 Effect of GC Oven Heating Rate: PCB Mix RT: He, 25 C min 1 NL: 2.73E5 TIC MS pcb-h-srm NL: 4.22E5 TIC MS pcb-h-srm H 2, C min No loss of resolution All this time space is intentionally left blank Time (min) 7 Polychlorinated Biphenyls Mix ran by Dirk Claus, Interscience,

8 Effect of Flow Rate C:\chem\...\November29.b\level8.d\level8 11/29/212 6:6:54 PM RT: Hydrogen 3 ml/min (115 cm/sec) NL: 1.35E8 TIC MS 2ng NL: 3.26E8 TIC MS level8 Hydrogen 1 ml/min (66 cm/sec) Helium 1 ml/min (44 cm/sec) NL: 3.18E8 TIC MS 2nghe1m lflowjbc Time (min) 8

9 Relative Abundance Relative Abundance Peak Shape and Critical Separations RT: H 2, 2 ml/min NL: 5.23E6 m/z= MS level5 RT: H 2 NL: 6.19E6 m/z= MS level He, 2 ml/min NL: 7.26E6 m/z= MS level Time (min) He RT: NL: E7 m/z= MS level Time (min) Indeno[1,2,3-cd]pyrene & benzo[g,h,i]perylene Time (min) Benzo[b&k]fluoranthene 9

10 Thermo Scientific Position on Hydrogen with GC-MS Hydrogen Kit Required to Run with H 2 Required for H 2 Specifications Includes Hydrogen Sensor Requires 3 L/s Turbo Pump Thermo Scientific Hydrogen Systems ISQ Single Quadrupole GC-MS TRACE 13 Series GC TSQ 8 GC-MS/MS Explosion Tested & Safety Certified Upgrades in the Field All existing ISQ GC-MS Systems are either already H 2 capable or are upgradeable with 3 L/s Turbo and H 2 Kit IF you decide to use your existing Thermo Scientific DSQ, DSQ II & ITQ GC-MS with H 2, you do so at your own risk (no Safety Certification) 1

11 ISQ GC-MS Hydrogen Carrier Installation Specifications ISQ Single Quadrupole GC-MS Guaranteed installation specifications with hydrogen carrier gas Choice of either He or H 2 on installation spec sign-off PCI/NCI same S/N! In EI mode, 1 μl of 1 pg/μl octafluoronaphthalene (OFN) will produce the following minimum signal to noise for m/z 272 when scanning from 3 u: In PCI mode, 1 μl of pg/μl benzophenone will produce the following minimum signal to noise for m/z 183 when scanning from 8 23 u using methane reagent gas: In NCI mode, 2 μl of fg/μl of OFN will produce the following minimum signal to noise for m/z 272 when scanning from 3 u using methane reagent gas: 1,:1 :1 3:1 3:1 6:1 6:1 11 * Requires Hydrogen Kit for H 2.

12 ISQ GC-MS Technical Brief - AB

13 Hydrogen Gas Safety Safety Precautions Hydrogen sensor in GC oven Venting hydrogen The risk is minimal Can be estimated & prevented Safety Facts on ISQ GC-MS and TSQ 8 GC-MS Explosion Tested & Explosion Certified No detaching/flying pieces even IF hydrogen inside goes boom It is really hard in practice to reach explosive limits of hydrogen in the lab space and the GC oven is monitored by the sensor 13

14 Hydrogen Purity Specifications GC-MS Hydrogen Generator O 2 <.1 ppm H 2 O < 1 ppm THC N/A Hydrogen Grade 5. UHP O 2 < 1 ppm H 2 O < 3 ppm THC <.1 ppm Hydrogen FID Fuel Grade O 2 < 1 ppm H 2 O < 3 ppm THC <.5 ppm Hydrogen Grade 6. UHP O 2 <.1 ppm H 2 O <.5 ppm THC <.1 ppm 14

15 Hydrogen Generators: Choose the Best 15

16 Understanding Hydrogen Plumbing Gas Filter, triple stage Tubing Stainless steel preferred 1/8 pre-cleaned New tubing is preferred over used with He Filter only need with tanks For removal of water, oxygen and hydrocarbons What you need to know about plumbing up hydrogen to your GC 16

17 Limits on Hydrogen Flow and Column Selection 1 ml/min hydrogen on.25 mm 3 m column 1 ml/min hydrogen on.18 mm 2 meter column 17

18 GC-MS Tuning Dealing with HC background ions and water Bake out at 3 C with hydrogen flow at 4 ml/min Mass Resolution: good Shows similar tune to that with helium Target Tuning for DFTPP and BFB Special tuning sequence to meet EPA tuning criteria 18

19 Bake-out at 3 C with H 4 ml/min for 1 hr FC-43 n-(c 4 F 9 ) 3 N DFTPP

20 Air Water Spectra: m/z 29 and m/z 19 m/z 18 m/z 19 m/z 28 m/z 29 m/z 18 m/z 28 2

21 Tuning Report: He vs. H 2 He H 2 21

22 EPA Method 827 Performance Mix (DFTPP) RT: Helium RT: 5.53 AA: BP: RT: 5.86 AA: BP: RT: 6.9 AA: BP: RT: 7.97 AA: BP: NL: 2.15E7 TIC MS ICIS DFTPP Hydrogen RT: 4.9 AA: 9723 BP: RT: 5.27 AA: BP: RT: 6.2 AA: BP: RT: 7.2 AA: BP: NL: 2.69E7 TIC MS ICIS DFTPP11 Peak 1 pentachlorophenol Peak 2 DFTPP Peak 3 benzidine Peak 4 p,p -DDT Time (min) 22

23 DFTPP (Decafluorotriphenylphosphine) Spectrum Helium NL: 2.73E6 dftpp4#1315 RT: 5.28 AV: 1 SB: T: {,} + c EI Full ms [35.-.] Hydrogen m/z NL: 4.4E6 DFTPP12#131 RT: 5.27 AV: 1 SB: T: {,} + c EI Full ms [35.-.] 23

24 EPA Method 827 EPA Method 827 Direct 1 µl liquid injection Calibration (1 2 ppm) More than 12 compounds Surrogates = 4 ppm Internal Standards = 4 ppm Goals Improve peak shape and resolution Improve method runtime (<15 minutes) Semi-volatile Organics 24

25 Method Parameters: EPA Method 827D Standards Prepared in ethyl acetate Calibration curve (1., 2., 5., 1,,, 2 ug/ml) Inlet S/SL: 325 C Split Mode: 15:1 Carrier: 1 ml/min H 2 Column TG-5 SilMS 2m x.18mm x.36 µm Oven: 1 min. 3 /min 1 min 2 /min 2 min 3 /min 3 min 2 /min 3.5 min MS Source 325 EC 15 uamps Full Scan 35- Scan speed 4,6 amu/ sec 25

26 EPA Method Criteria Tuning EPA Method 525/827: DFTPP EPA Method 524: BFB Calibration Establish working range for each method (measurement of accuracy) Method Detection Limits (MDLs) 26

27 Target DFTPP H 2 Tuning Report in Target Software 27

28 DFTPP (Decafluorotriphenylphosphine) Spectrum Helium NL: 2.73E6 dftpp4#1315 RT: 5.28 AV: 1 SB: T: {,} + c EI Full ms [35.-.] Hydrogen m/z NL: 4.4E6 DFTPP12#131 RT: 5.27 AV: 1 SB: T: {,} + c EI Full ms [35.-.] 28

29 Ion Ratio Stability for DFTPP 29

30 827: Comparison of Hydrogen to Helium Run Times C:\chem\...\level8.d\level8 12/5/212 2:4:3 PM RT: Hydrogen NL: 5.35E8 TIC MS level Helium NL: 1.12E8 TIC MS 39112_ Time (min)

31 Low Level PNAs in SIM RT: NL: 1.65E7 TIC MS 5ng Time (min) 31

32 Calibration Curves: Naphthalene & Benzo(g,h,i)perylene 32

33 Linear Fit of Low Level PNAs in SIM (.5 to 1 ppm) Compound %RSD Compound %RSD naphthalene 6.1 flouranthene methylnaphthalene 8.7 benzo(a)anthracene methylnaphthalene 7.7 chrysene 5.9 acenaphthylene 8.5 benzo(b)fluoranthene 8.6 acenaphthene 8.5 benzo(k)fluoranthene 9.2 flourene 8.5 benzo(a)pyrene 7.8 phenanthene 3.8 indeno(1,2,3,c,d)pyrene 5.1 anthracene 7. dibenz(a,h)anthracene 5.4 pyrene 3.6 benzo(g,h,i)perylene 6. acenaphthene-d1 4.6 phenanthene-d1 4.5 chrysene-d perylene-d

34 Low Level PNAs ppb (+/- %) Accuracy

35 Spectral Purity: NIST Library Match 35

36 827 Sensitivity and IDLs 36

37 EPA Methods 524 and 525 Drinking water EPA Method 524 Purge & Trap 5 ml sample volume Calibration (.4 2 ppb) EPA Method 525 Direct 1 µl liquid injection 1 liter sample volume Calibration (.1 1 ppm) Volatile and Semi-volatile Organics 37

38 Method Parameters: EPA Method Purge & Trap: 5 ml sample VOCARB Purge 11 min Dry Purge 1 min Desorb 24 2 min Oven 1 min. 3 /min 1 min 2 /min 2 min 3 /min 3 min Inlet S/SL: 2 Split : 4:1 Carrier:.7 ml/min H 2 Column: TG VMS.18 mm x 2 m x 1. µm MS Source 275 EC FS min 25 uamps Scan Speed 1,687 amu/sec 38

39 Method Parameters: EPA Method Standards Prepared in ethyl acetate Calibration curve (.1,.5, 1., 2., 5., 1 ug/ml) Oven: 1 min 3 /min 1 min 2 /min 2 min 3 /min 3 min 2 /min Inlet S/SL: 325 C Split Mode: 15:1 Carrier: 1 ml/min H 2 Column TG-5 SilMS 2m x.18mm x.36 µm MS Source 325 EC 15 uamps Full Scan 35- Scan speed 4,6 amu/ sec 39

40 BFB (1-bromo-4-fluorobenzene) Helium NL: 1.92E _a1# RT: AV: 4 SB: F: {,} + c EI Full ms Hydrogen NL: 5.25E5 blk11# RT: AV: 4 SB: F: {,} + c EI Full ms m/z 4

41 Target BFB (4-Bromofluorobenzene) H 2 Tuning Report 41

42 BFB Ion Ratio Stability m/z Criteria run1 run2 run3 run4 run5 run6 run7 run8 run9 run1 run % >3% % % < 2% of >% % of % of % of

43 Performance: EPA Method ppm Standard RT: NL: 3.E7 TIC MS 1ng Time (min) 43

44 Performance: EPA Method Method parameters Spectral integrity #1 Match to NIST Accuracy(.4 2 ppb): Passed at all levels Average MDL:.74 ppb vs.48 ppb in helium BFB Ion ratio stabile Passes QC for EPA Method

45 Performance: EPA Method ppb Standard F:\524\2ppbB_ /8/213 3:31:6 PM RT: NL: 8.77E7 TIC MS 2ppbB_ Time (min)

46 EPA Method 525: Measurement of Accuracy (+/- %) 2 1 +/ % ppb Standard Failed pentachlorophenol terbacil metribuzin bromacil chlorpyrifos trans-nonachlor carboxon Dieldrin tricyclazole Calibration:.1,.5,1,2,5,1 ppm in Full Scan 46

47 Spectral Purity NIST Library Match 47

48 Gases at 2 ppt RT: SM: 7B RT:.93 AA: 9279 BP: 85 dichlorodifluoromethane NL: 7.88E3 m/z= F: {,} + c EI Full ms [47.-3.] MS ICIS 2pptC RT: 1.4 AA: BP: chloromethane NL: 2.67E4 m/z= -51 F: {,} + c EI Full ms [47.-3.] MS ICIS 2pptC RT: 1.9 AA: BP: 62 vinylchloride NL: 1.51E4 m/z= F: {,} + c EI Full ms [47.-3.] MS ICIS 2pptC RT: 1.29 AA: BP: 94 bromomethane NL: 1.3E4 m/z= F: {,} + c EI Full ms [47.-3.] MS ICIS 2pptC RT: 1.8 AA: 5325 BP: 64 RT: 1.38 AA: BP: 64 chloroethane NL: 9.91E3 m/z= F: {,} + c EI Full ms [47.-3.] MS ICIS 2pptC RT: 1.47 AA: BP: 11 trichlorofuoromethane NL: 1.11E4 m/z= F: {,} + c EI Full ms [47.-3.] MS ICIS 2pptC Time (min) 48

49 Accuracy of 4 ppt - Passed +/- %.6.5 methylenechloride E

50 Moving to Hydrogen for your Environmental Analyses The world leader in serving science

51 Moving To Hydrogen on the GC Side Hydrogen Sensor is a Must In GC oven Possible on the hydrogen generator May also be required at the ceiling of the lab Expect Lower Inlet Pressure Due to viscosity differences of H 2 and He Move to a smaller id column 51

52 Moving to Hydrogen on the MS Side NO MS hardware change required to meet H 2 Installation Specs Maintain good vacuum Extended performance turbomolecular pumps 9.8 x 1-6 Torr (1 ml/min hydrogen flow) Higher initial background Minimized with stainless steel pre-cleaned tubing UHP Grade 5. or better Hydrogen Source Bake out source at 3 C for one hour with filament on CI Effect on some compounds Require linear or quadratic fit Reduce flow rate of H 2 into MS Pressure dependency: Minimize solvent vapor with smaller id columns ISQ Off-Axis Single Quadrupole GC-MS 52

53 Conclusion: Moving to Hydrogen Carrier Gas Considerations Gas purity Safety Column selection Column flow rate Mass spectrometer modifications: Hydrogen kit Meets QC requirements for EPA Method 524 and

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