New GCMS Applications

Transcription

1 New GCMS Applications Analysis of Trace Fatty Acid Methyl Esters (FAME) in Jet Fuel, Sample Characterization by GCxGC/FID/MSD, Crude Oil Biomarkers Malgorzata Sierocinska Agilent Technologies Waldbronn 1

2 Introduction Increasing quantities of biodiesel and jet are being co-transported in multiproduct pipelines (MPP) In MPP transportation trace amounts of FAME can be found in jet parcels following biodiesel parcels due to FAME trail back. Following pipeline trials to establish the amount and profile of FAME trail back into jet fuel JIG PQ committee work on the effect of various FAMEs (up to 400 ppm) on the specification properties of jet fuel the main engine Commercial aircraft OEMs gave approval of limit of 5 mg/kg total FAME in jet fuel New method developed using single column GC/MS to detect individual FAMEs from 0.5 mg/kg to 50 mg/kg IP PM-DY/09 Method for Determination of FAME in Jet Fuel GC/MS with Selected Ion Monitoring 2

3 IP PM-DY/09 Method for Determination of FAME in Jet Fuel GC/MS with Selected Ion Monitoring 7890A GC Conditions: 5975C MSD Settings: Inlet: Electron ionization (EI) at 70 ev Temperature: 260 o C Source Temperature: 230 o C Mode: splitless Quad Temperature: 150 o C Sample size: 1 ul Scan Range: m/z 33 to m/z 320 SIM Groups: see next slide Column: HP-Innowax, 50m x 0.20 mm ID x 0.4 um Flow: 0.6 ml/min helium constant flow mode GC Oven: Initial temperature: 150 o C for 5 min. Ramp 1: 20 o C/min to 200 o C for 17 min. Ramp 2: 3 o C to 252 o C for 2 min. 3

4 Mass Spec SIM Ions Used for FAME Quantification FAME Species SIM Ions SIM Group Start Time Methyl Palmitate (C16:0) Methyl Heptadecanoate (C17:0)* 270 (mol. ion), 271, 239, min. 284 (mol. ion), 253, min. Methyl Stearate (C18:0) 298 (mol. Ion), 267, min. Methyl Oleate (C18:1) Methyl Linoleate (C18:2) Methyl Linolenate (C18:3) 296 (mol. ion), 265, min. 294 (mol. ion), 295, 264, 263, min. 292 (mol. ion) 293, 263, min. *C17:0 added to accommodate biodiesel made from animal fats 4

5 SIM/SCAN of Calibration Standard 0.5 mg/kg Each FAME in Dodecane Scan TIC C16:0 C17:0 C18:0 C18:1 C18:2 C18:3 SIM TIC 5

6 FAME Calibration 0 to 5 mg/kg Method uses this calibration for samples containing total FAME below 5 mg/kg C16:0 R² = C18:0 R² = C17:0 R² = C18:1 R² = C18:2 R² = C18:3 R² = C17:0 C16:0 C18:0 C18:1 C18:2 C18: ,5 1 1,5 2 2,5 3 3,5 4 4,5 5 6

7 Matrix Induced Retention Time Shifts of FAME Peaks Sample matrix can shift FAME peaks outside of their detection windows C16: min. 50 mg/kg FAME Calibration Standard 50 mg/kg Each FAME Spiked in Jet Fuel C17: min. C18: min. C18: min. C18: min. C18: min

8 5 mg/kg and 1 mg/kg Total FAME Spiked in Jet Fuel Sample 1 Abundance Jet Fuel Blank mg/kg Total FAME Spike C16:0 C17:0 C18: mg/kg Total FAME Spike C18:1 C18:2 C18: Min. 8

9 Qunatitative Results for 5 mg/kg and 1 mg/kg Total FAME Spiked in Jet Fuel Sample 1 5 mg/kg Total FAME Spike FAME Run 1 Run 2 Run 3 Std Dev C16: C17: C18: C18: C18: C18: Total mg/kg Total FAME Spike FAME Run 1 Run 2 Run 3 Std Dev C16: C17: C18: C18: C18: C18: Total

10 Matrix Interference in Jet Fuel Sample 2 Interferences change depending on type of jet fuel 0.9 mg/kg Each FAME Spiked Second Jet Fuel Sample 0.5 mg/kg Std of Each FAME Min. 10

11 Known Matrix Effects Raised C16:0 Detection Limit Data courtesy of Tom Lynch, BP Abundance Abundance C16:0 C18: mg/kg 2 mg/kg mg/kg 2 mg/kg mg/kg 0.5 mg/kg mg/kg 0.5 mg/kg mg/kg mg/kg Reference fuel Time--> Time--> Reference fuel 11

12 Dean s Heartcutting to Remove Matrix Interferences FID Restrictor S/S Inlet Aux EPC HP-Innowax MSD HP-5ms Capillary Flow Technology Deans Switch 12

13 MDGC Method:GC/MS Instrument Conditions Inlet: Temperature: 260 o C Mode: splitless Sample size: 1 ul Column 1: HP-Innowax, 30m x 0.25 mm ID x 0.5 um Flow: 1.0 ml/min He constant P (225 o C) Column 2: HP-5ms, 30m x 0.25mm ID x 0.25 um Flow: 2.0 ml/min He constant P (225 o C) CC Oven: Initial temperature: 150 o C for 5 min. Ramp 1: 20 o C/min to 200 o C for 17 min. Ramp 2: 3 o C to 252 o C for 2 min. MSD Settings: Electron ionization (EI) at 70 ev Source Temperature: 230 o C Quad Temperature: 150 o C Scan Range: m/z 33 to m/z 320 SIM Groups: see next slide Restrictor: 0.7m x 0.1 um ID deactivated fused silica 13

14 FID Signal Used to Set Heart-Cut Times Primary Column: HP-Innowax AVTUR Blank AVTUR 100 mg/kg Total FAME Spike FAME Primary Column Retention Time (min.) Heart-Cut Time (min.) C16: C17: C18: C18: C18: C18: Wider cut windows used to account for matrix induced retention time shifts 50 mg/kg Total FAME Std

15 Improve SIM Ion Groups for FAME Peaks Hydrocarbon mass peaks (mostly aromatics) in co-eluting jet fuel have little overlap with most FAME mass peaks Prototype Software recommends SIM ions to reduce background interference and improve S/N in the target peak elution time Jet Fuel Blank Average Spectra min ppm C16:0 Standard Average Spectra min

16 Expand SIM Ions Groups to Include FAME Base Peaks FAME Species SIM Ions SIM Group Start Time Methyl Palmitate (C16:0) Methyl Heptadecanoate (C17:0) 270(mol. ion), 271, 239, 227, 74(base) 284(mol. ion), 253, 241, 74(base) 20 min. 28 min. Methyl Stearate (C18:0) 298(mol. Ion), 267, 255, 74(base) 32 min. Methyl Oleate (C18:1) Methyl Linoleate (C18:2) Methyl Linolenate (C18:3) 296(mol. ion), 265, 264, 55(base) 294(mol. ion), 295, 264, 263, 262, 67(base) 292(mol. ion) 293, 263, 236, 79(base) 35.5 min min. 39 min. 16

17 HP-5ms Secondary Column Elution of FAMES After Heart-Cut HP-5ms Column MS Scan Data C16:0 C17:0 C18:0 C18:1 C18:2 C18:3 HP-5ms Column MS SIM Data Innowax Column FID Data C16:0 C17:0 C18:0 C18:1 C18:2 C18:3 17

18 Combination of Heart-Cutting MDGC and Base Peak SIM Ions 1 mg/kg total FAME Spiked in Jet Fuel Sample 2 (< 0.2 mg/kg each FAME) Improved detection of C16:0 FAME Better(?) detection of C17:0 C18:0, C18:2 and C18:3 Added matrix interference with C18:1 FAME C18: C16: C17: C18: C18: C18: Min. 18

19 Basic system layout for GCxGC FID/MSD Auto-sampler Switching valve s/s inlet PCM FID MS Tee 1 st column modulated 2 nd column Column 1 Column 2 Flow modulator MSD 19

20 Flow Modulator Diagram for Operation with the 5975C MSD Flow Modulation Interface for the MSD Second column MOD MSD 171mm x 110um restrictor Restrictor (0.4M x 0.25mm) FID MS Tee 20

21 GC Image processing of MSD GCxGC data TIC of heavy gasoline Spectra are library searchable 21

22 22 Kerosene: GCxGC with MSD

23 TIC: B20 Soy Biodiesel 23

24 C18:2 Mass Spectrum 24

25 5975C GCxGC Scan: amu 19 scans/sec. (2.3 scans) Scan range Scans/sec Scans/peak Naphthalene 2. Methyl naphtalenes 3. Dimethy naphthalenes 4. 1 methyl 4- phenyl methyl benzene 5. Anthracene 6. Methly phenanthrene 7. 9,10 dimethyl phenanthrene 8. n-c23 25

26 Paraffins and Olefins Mix ,8-Nonadiene 2. 1-Nonene 3. Nonane 4. 1,9 Decadiene 5. 1 Decene 6. 4 Decene 7. Decane 8. 3 Undecene 9. Undecane Decene 11. Dodecane Tridecene 13. Tridecane Tetradecene 15. Tetradecane 26

27 Paraffin and Aromatics Mix Nonane 2. 3-methyl nonane 3. Decane 4. 3-methyl decane 5. Undecane 6. 3-methyl 1-undecane 7. Dodecane 8. 4-methyl-dodecane 9. 3-methyl-dodecane 10. Tridecane 11. Tetradecane 12. Butyl benzene methyl 4 propyl benzene methyl-4-(1-methylpropyl)-benzene 15. Pentylbenzene methyl butyl benzene 17. Hexyl benzene 18. 1,3 dimethyl butyl benzene methyl hexyl benzene methyl 2-n-hexyl benzene butylhexyl-benzene propyl heptyl-benzene 27

28 MSD as a Standard GC Detector 1.Easy setup wit autotune 2. Possibility of using e-methods 3. Sensitivity and positive confinfirmation 4. Possibility of creating RTL methods with associated libraries 5. Possibility of column backflush to keep the ion source clean 6. High reliability 7. Compact and easy to service 28

29 Biomarkers in Crude Oil Biomarkers are important in petroleum exploration for determining the age, biological source, and geological history of crude oils. They also allow characterization of crude oils in refineries and environmental monitoring. The characterization of crude oils for biomarkers is commonly performed by capillary GC in combination with HRMS or SIM. The application of SRM with a unique configuration of the GC allows for extended detection limits, higher throughput and higher analytical quality. 29

30 Experimental configuration 7890A GC Pressure / Flow Controller 7000A Injection Port Pulsed Splitless EI mode (70 ev) (300 C) Purged Ultimate Union 1.22 ml/min SRM mode Source 230 C 1.2 ml/min Column 1 Column 2 30

31 Analysis Speed 40m column 60m column 40 min 70 min Run times can be accelerated 30 minutes per cycle without loss in chromatographic resolution or substantial loss in signal by switching from a 60m column with He carrier gas to a 40m column with H2. The speed of the 7000A Triple Quadrupole mass spectrometer in SRM mode required only a change in dwell time from 50 to 20 msec to record the required 17 transitions with the same number of scans over the peaks. An experimental comparison with an uninterrupted 60m column (not shown) demonstrates that the use of the Pressure Controlled Tee configuration results in no degradation in chromatography. 31

32 Increased Throughput with Backflushing Backflush for faster turnaround, less carryover, and stable baselines Target compounds High boiling compounds seen in following solvent blank No Backflush Clean Solvent Blank With Backflush 32

33 Analytical Precision of MS-MS Reproducible biomarker concentrations in complex petroleum samples 33

34 34 Control Chart View

35 Linearity and Dynamic Range: Deconvolving Oil Mixtures A sophisticated understanding of petroleum systems requires the accurate deconvolution of oil mixtures derived from multiple source rocks. This problem is common where stacked source rocks exist in sedimentary basins. 35

36 36 Linearity and Dynamic Range: Deconvolving Oil Mixtures

37 Conclusions Advantages of using SRM over SIM identified thus far include increased sensitivity, better selectivity and the potential to greatly reduce analysis time Column backflush provided higher throughput with lower carry over Hydrogen and narrower bore columns reduced the run time nearly two-fold The scan speed, linearity, dynamic range and transition ratio stability of the triple quadrupole mass spectrometer allow the quantitative characterization and fingerprinting of petroleum samples and the deconvolution of petroleum mixtures. 37