View
224
Download
0
Category
Preview:
Citation preview
New GCMS Applications
1
Malgorzata SierocinskaAgilent Technologies Waldbronn
Analysis of Trace Fatty Acid Methyl Esters (FAME) in Jet Fuel, Sample Characterization by GCxGC/FID/MSD, Crude Oil Biomarkers
Introduction
• Increasing quantities of biodiesel and jet are being co-transported in multi-product 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
IP PM-DY/09 Method for Determination of FAME in Jet Fuel – GC/MS with Selected Ion Monitoring
7890A GC Conditions:
Inlet:
• Temperature: 260 oC• Mode: splitless• Sample size: 1 uL
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 oC for 5 min.• Ramp 1: 20 oC/min to 200 oC for 17 min.• Ramp 2: 3 oC to 252 oC for 2 min.
5975C MSD Settings:
• Electron ionization (EI) at 70 eV• Source Temperature: 230 oC• Quad Temperature: 150 oC• Scan Range: m/z 33 to m/z 320• SIM Groups: see next slide
3
Mass Spec SIM Ions Used for FAME Quantification
FAME Species SIM Ions SIM Group Start Time
Methyl Palmitate (C16:0) 270 (mol. ion), 271, 239, 227 20 min.
Methyl Heptadecanoate (C17:0)* 284 (mol. ion) , 253, 241 28 min.
Methyl Stearate (C18:0) 298 (mol. Ion), 267, 255 32 min.
Methyl Oleate (C18:1) 296 (mol. ion), 265, 264 35.5 min.
Methyl Linoleate (C18:2) 294 (mol. ion), 295, 264, 263, 262 36.5 min.
Methyl Linolenate (C18:3) 292 (mol. ion) 293, 263, 236 39 min.
*C17:0 added to accommodate biodiesel made from animal fats
4
SIM/SCAN of Calibration Standard0.5 mg/kg Each FAME in Dodecane
C16:0C17:0
C18:0 C18:1C18:2
C18:3Scan TIC
SIM TIC
5
FAME Calibration – 0 to 5 mg/kg
6
C17:0 R² = 0.9998
C16:0 R² = 0.9998
C18:0 R² = 0.9999
C18:1 R² = 0.9999
C18:2 R² = 0.9997
C18:3 R² = 0.9997
0
20000
40000
60000
80000
100000
120000
140000
160000
0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5
C17:0
C16:0
C18:0
C18:1
C18:2
C18:3
Method uses this calibration for samples containing total FAME below 5 mg/kg
Matrix Induced Retention Time Shifts of FAME Peaks
26 28 30 32 34 36 38 40
C18:3+0.054 min.
C18:2+0.067 min.
C18:1+0.076 min.
C18:0+0.083 min.
C17:0+0.098 min.
C16:0+0.138 min.
50 mg/kg FAME Calibration Standard
50 mg/kg Each FAME Spiked in Jet Fuel
Sample matrix can shift FAME peaks outside of their detection windows
7
5 mg/kg and 1 mg/kg Total FAME Spiked in Jet Fuel Sample 1
20 22 24 26 28 30 32 34 36 38 40 42 440
2000
6000
10000
14000
18000
22000
Abundance
Min.
Jet Fuel Blank
1 mg/kg Total FAME Spike
5 mg/kg TotalFAME Spike
C18:3
C18:2C18:1
C18:0C17:0C16:0
8
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
C16:0 0.8 0.8 0.8 0.02
C17:0 0.9 0.8 0.8 0.01
C18:0 0.9 0.9 0.9 0.01
C18:1 0.8 0.8 0.8 0.01
C18:2 0.9 0.9 0.9 0.04
C18:3 0.9 0.9 0.9 0.02
Total 5.2 5.0 5.0 0.10
1 mg/kg Total FAME Spike
FAME Run 1 Run 2 Run 3 Std Dev
C16:0 0.3 0.5 0.5 0.09
C17:0 0.1 0.1 0.1 0.02
C18:0 0.1 0.1 0.1 0.02
C18:1 0.2 0.1 0.1 0.02
C18:2 0.2 0.2 0.2 0.01
C18:3 0.2 0.2 0.1 0.03
Total 1.0 1.2 1.2 0.12
9
Matrix Interference in Jet Fuel Sample 2
20 22 24 26 28 30 32 34 36 38 40 42 44 Min.
0.5 mg/kg Std of Each FAME
0.9 mg/kg Each FAME Spiked Second Jet Fuel Sample
Interferences change depending on type of jet fuel
10
Known Matrix Effects Raised C16:0 Detection Limit
22.90 23.00 23.10 23.20 23.30 23.40 23.50 23.60 23.70
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
24000
26000
28000
30000
32000
34000
36000
38000
Time-->
Abundance
5 mg/kg
2 mg/kg
1 mg/kg
0.5 mg/kg
0.1 mg/kg
Data courtesy of Tom Lynch, BP
35.10 35.20 35.30 35.40 35.50 35.60 35.70 35.80 35.90 36.00 36.10 36.20 36.30 36.40 36.50
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
11000
Time-->
Abundance
Reference fuel
5 mg/kg
2 mg/kg
1 mg/kg
0.5 mg/kg
0.1 mg/kg
Reference fuel
C16:0 C18:1
11
Dean’s Heartcutting to Remove Matrix Interferences
FID
S/S Inlet
MSD
Restrictor
HP-Innowax
HP-5ms
Aux EPC
Capillary Flow TechnologyDeans Switch
12
MDGC Method:GC/MS Instrument Conditions
Inlet:• Temperature: 260 oC• 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 oC)
Column 2:• HP-5ms, 30m x 0.25mm ID x 0.25 um• Flow: 2.0 mL/min He constant P (225 oC)
Restrictor: 0.7m x 0.1 um ID deactivated fused silica
CC Oven:
• Initial temperature: 150 oC for 5 min.• Ramp 1: 20 oC/min to 200 oC for 17 min.• Ramp 2: 3 oC to 252 oC for 2 min.
MSD Settings:• Electron ionization (EI) at 70 eV• Source Temperature: 230 oC• Quad Temperature: 150 oC• Scan Range: m/z 33 to m/z 320• SIM Groups: see next slide
13
FID Signal Used to Set Heart-Cut Times
50 mg/kg Total FAME Std
AVTURBlank
AVTUR 100 mg/kg Total
FAME Spike
22 24 26 28 30 32 34 36 38 40
FAMEPrimary Column Retention Time
(min.)
Heart-Cut Time (min.)
C16:0 24.080 23.7 – 24.6C17:0 29.151 28.9 – 29.5C18:0 33.798 33.5 – 34.1C18:1 34.841 34.5 – 35.1C18:2 36.825 36.6 – 37.2C18:3 39.570 39.3 – 39.9
Primary Column: HP-Innowax
Wider cut windows used to account for matrix induced retention time shifts
14
Improve SIM Ion Groups for FAME Peaks
40 60 80 100 120 140 160 180 200 220 240 260 280 300 320
167
115 1901417751 210 230 258 304
40 60 80 100 120 140 160 180 200 220 240 260 280 300 320
74
43143 227 270185 239
Jet Fuel BlankAverage Spectra25.5 – 25.8 min.
5 ppm C16:0 StandardAverage Spectra25.5 – 25.8 min.
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
15
Expand SIM Ions Groups to Include FAME Base Peaks
FAME Species SIM Ions SIM Group Start Time
Methyl Palmitate (C16:0) 270(mol. ion), 271, 239, 227, 74(base) 20 min.
Methyl Heptadecanoate (C17:0) 284(mol. ion) , 253, 241, 74(base) 28 min.
Methyl Stearate (C18:0) 298(mol. Ion), 267, 255, 74(base) 32 min.
Methyl Oleate (C18:1) 296(mol. ion), 265, 264, 55(base) 35.5 min.
Methyl Linoleate (C18:2) 294(mol. ion), 295, 264, 263, 262, 67(base) 36.5 min.
Methyl Linolenate (C18:3) 292(mol. ion) 293, 263, 236, 79(base) 39 min.
16
HP-5ms Secondary Column Elution of FAMES After Heart-Cut
C16:0 C17:0 C18:0 C18:1 C18:2 C18:3
HP-5ms ColumnMS Scan Data
HP-5ms ColumnMS SIM Data
Innowax ColumnFID Data
C16:0C17:0
C18:0 C18:1C18:2 C18:3
17
Combination of Heart-Cutting MDGC and Base Peak SIM Ions
• 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
26 28 30 32 34 36 38 40
C16:027.399 C17:0
32.133
C18:036.545
C18:137.336
C18:239.110
C18:341.558
Min.
1 mg/kg total FAME Spiked in Jet Fuel Sample 2(< 0.2 mg/kg each FAME)
18
Basic system layout for GCxGC FID/MSD
Auto-sampler
FID
Column 1
Flow modulator
s/s inletPCM
Switching valve
modulated
2nd column
1st column
Auto-sampler
FID
Column 1 Column 2Column 2
s/s inletPCM
Switching valve
modulated
2nd column
1st column
MSD
MS Tee
19
Flow Modulator Diagram for Operation with the 5975C MSD
Flow Modulation Interface for the MSD
MS Tee
Flow Modulation Interface for the MSD
MS Tee
171mm x 110um restrictor
Second column
Restrictor (0.4M x 0.25mm)FID
MOD
MSD
Second column
Restrictor (0.4M x 0.25mm)FID
MOD
MSD
20
GC Image processing of MSD GCxGC dataTIC of heavy gasoline
Spectra are library searchable
21
Kerosene: GCxGC with MSD
22
TIC: B20 Soy Biodiesel
23
C18:2 Mass Spectrum
24
25
5975C GCxGC
1. Naphthalene2. Methyl naphtalenes3. Dimethy naphthalenes4. 1 methyl 4- phenyl methyl benzene5. Anthracene6. Methly phenanthrene7. 9,10 dimethyl phenanthrene8. n-C23
Scan: 50 -375 amu
19 scans/sec. (2.3 scans)Scan range Scans/sec Scans/peak
50 - 200 28 3.350 - 300 22 2.6
Paraffins and Olefins Mix
12
3456
7 8 9 10 11 1213 1415
1. 1,8-Nonadiene2. 1-Nonene3. Nonane4. 1,9 Decadiene5. 1 Decene6. 4 Decene7. Decane
8. 3 Undecene9. Undecane10. 4 Decene11. Dodecane12. 2 Tridecene13. Tridecane
14. 5 Tetradecene15. Tetradecane
26
Paraffin and Aromatics Mix
1 2 34
5 6 7 8 9 10 11
1213
14 1516 1718
19
20
2122
1. Nonane2. 3-methyl nonane3. Decane4. 3-methyl decane5. Undecane6. 3-methyl 1-undecane7. Dodecane8. 4-methyl-dodecane9. 3-methyl-dodecane10. Tridecane11. Tetradecane
12. Butyl benzene13. 1-methyl 4 propyl benzene14. 1-methyl-4-(1-methylpropyl)-benzene15. Pentylbenzene16. 1-methyl butyl benzene17. Hexyl benzene18. 1,3 dimethyl butyl benzene19. 1-methyl hexyl benzene20. 1-methyl 2-n-hexyl benzene21. 1-butylhexyl-benzene22. 1-propyl heptyl-benzene
27
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
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.
Biomarkers in Crude Oil
29
Experimental configuration
Pressure / Flow Controller
Column 1
Purged Ultimate Union
EI mode (70 eV)
SRM mode
Source 230°C
7890A GC
Injection Port
Pulsed Splitless
(300°C)
1.2 ml/min
1.22 ml/min
7000A
Column 2
30
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.
Analysis Speed
↑40 min
↑70 min
40m column 60m column
31
Increased Throughput with BackflushingBackflush for faster turnaround, less carryover, and stable baselines
Targetcompounds High boiling compounds
seen in following solvent blank
No Backflush
With Backflush
Clean Solvent Blank
32
Analytical Precision of MS-MSReproducible biomarker concentrations in complex petroleum samples
33
Control Chart View
34
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.
Linearity and Dynamic Range: Deconvolving Oil Mixtures
35
Linearity and Dynamic Range: Deconvolving Oil Mixtures
36
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.
Conclusions
37
Recommended