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Ultra Fast GC Determination of Total Hydrocarbons (C7-C40) and BTEX in Water and Soils through Direct Resistively Heated capillary columns and Robotic Autosampler.
Fausto Munari e Andrea Cadoppi
ThermoFisher - Italy
2
Summary
Official regulations for Total Hydrocarbons: GC as replacement of IR
Ultra Fast GC and Triplus Autosampler
ISO 9377-2 with Ultra Fast GC
ISO 9377-2 (Mod.) with Ultra Fast GC
3
IR and GC methods
Method: EPA 418.1 ISO 9377-2TNRCC 1005 EPA 8015
Analysis Time: around 2 min 20 min
Infra Red GC
Extraction Solvent: CCl4, Freon n-pentane,(banned) n-hexane
TTCE
ISO/TR 11046 ISO/TR 11046(for Oil in soil and sediments)
2 minby Ultra Fast GC
4
How fast is UFGC?
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
50 100 150 200 250 300 350
Final oven temperature (°C)
Rat
e (°
C/m
in)
0
2
4
6
8
10
12
14
16
18
20
22
24
Rat
e (°
C/s
)
UFGC (direct resistive heating)
Conventional “fast” oven
5
Ultra Fast GC: Requirements
• Ultra Fast heating capability (100-1200 °C/min)
• Short capillary columns (typically 2-5m narrow-bore; or 0.32mm i.d. when separation power is not an issue)
• High pressure pneumatic control capability
• Fast Detector (High Frequency Response)
6
Direct column heating technology
The heating element and the T sensorare wrapped around the columnThe column is mounted in a “cage”ULTRA FAST Column Module
Dedicated heated interfaces forinjector and detector NO oven heating is required
The column module includes bothheating and temperature sensingelements
Capillary column
Heater
Temperature sensor Ceramic fiber
Column assembly
7
The column module in the oven
Column modules are housed in the GC oven and connected to inlet (SSL or PTV) and detector as a conventional capillary column
Configurations used for TPH analysis:
• SSL / FID• PTV / FID
FID Injector
Additional heated block
Trace GC Ultra oven
8
Trace GC Ultra Column Module
Assemblies of 2, 5, 10 m (0.1-0.32 mm i.d.)
Up to 20°C/s (1200 °C/min) temperature programming rates
Broad temperature range (from 35 to 370°C)
Cooling from 350°C to 50°C in about 1 min
If needed, also cryo cooling is available (0°C minimum temp)
FEATURES
Significant implications over conventional GC
• Faster analysis times• Higher column lifetime• Higher sensitivity: capability to handle trace analysis
9
0.0E+00
2.0E+04
4.0E+04
6.0E+04
8.0E+04
1.0E+05
1.2E+05
1.4E+05
1.6E+05
0 1 2 3 4 5 6 7 8 9 10
time (s)
FID
sig
nal (
uV)
300 °C/min 0.1 mm id column
PW1/2 = 0.10 s
20 °C/min 0.32 mm id column
PW1/2 = 1.6 s
nC20 (about 1ng) area 15000 (uV.s)
Increased sensitivity - Peak compression effect
Narrower peaks result in better signal to noise ratio
10
Ultra Fast Analysis of FAME
∼ 20 min
∼ 1 min
Classical Analysis30 m, 0.32 mm id, 0.25 um Column TR-510 °C/min
Ultra Fast GC Analysis5m, 0.10 mm id, 0.10 um Column TR-5300 °C/min
E7
E9
E10
E11 E
12
E13
E14
E15
E16
E17
E18
E19
E20E
8
E12 E13
E7
E9
E10
E11 E14
E15
E16
E17
E18
E19
E20E8
1 min
11
Retention Time repeatability study
nC25
nC23
nC22
nC20
9
8
7
6
nC185
nC164
nC143
nC122
nC101
Components
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0
2 °C /s
1 0 °C /s
5 °C /s
35 s
60 s
110
s
Time (s)
1 2 3 46
5
7 8 9
10 °C/s
5 °C/s
2 °C/s
Carrier gas mode: constant flow(1 ml/min H2)Column 5m x 0.1 mm id, 0.1 um TR-570 to 330 °CSplit 1:200
12
Retention Time repeatability
• Clear Identification: SD << peak width
at ½ h at 5% h6×SD
window*Peak widthsRetention times
ComponentRate (°C/s)
0.1080.1700.0850.01829.95C25
0.0960.1450.0700.01625.54C20
0.054
0.096
0.084
0.084
0.090
0.090
0.090
0.090
0.096
0.168
0.120
0.135
0.230
0.199
0.180
0.180
0.470
0.420
0.360
0.400
0.0550.00915.98C12
0.0600.01612.68C10
10
0.1100.01450.56C25
0.0900.01441.99C20
0.0800.01523.26C12
0.0900.01516.56C10
5
0.2200.015106.69C25
0.2000.01585.26C20
0.1800.01639.01C12
0.1800.02823.35C10
2
SD (s)Mean (s)
* In a ± 3 SD span there is a probability of 99.7 % for a measure to fall in
13
ISO 9377-2
ISO Norm 9377-21. Extraction of 900ml of water with 50 ml of n-hexane
2. Purification of the extract through Florisil, to removeinterferences
3. Concentration of the extract from 50 to 1ml4. GC analysis (FID detector)
Solvent: n-hexane
Range of hydrocarbons: C10-C40
14
Hydrocarbon analysis in water and soils
Column :TR- 5m, 0.32 mm id, 0.25 um FT, T prog.: 40 (20s), 3.3 °C/s, 350 (30s), Sample: Soil extract (50 ng/ul tot hyd.), Injection: 1 ul SPLITLESS, Splitless time: 20 s, Carrier: He at 5 ml/min CF
Splitless injection
Soil extract (50 mg/l tot. hydroc.)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
time (min)
C40C10
2 minTotal hydrocarbons
15
Calibration curve 5-500 mg/lR2 0.9999
0
200
400
600
800
0 100 200 300 400 500 600Concentration (mg/l)
Are
a co
unts
(*10
^6)
Hydrocarbon analysis in water and soils
High linearity from 5 to 500 mg/lC40/C20 area ratio > 0.9 (required 0.8)RSD% on group peak absolute area 0.8%
16
Trace GC Ultra
SSL - UFM - Fast FID
Compliance with the requirements of the official methods
High sample/day throughput!
100 samples in about 8h (a work-day)!
SamplingRun Time 5 minCooling Time
ISO 9377-2
17
ISO 9377-2
Gain in speed• Faster run• Faster cooling
Gain in sensitivity• Peaks compression:
peaks are narrower and consequently higher
0
2 5 0
5 0 0
7 5 0
1 0 0 0
1 2 5 0
1 5 0 0
1 7 5 0
2 0 0 0
2 2 5 0
0 2 0 4 0 6 0 80 1 00 1 2 0
(s e c)
(mV
olt)
0
2 50
5 00
7 50
1 0 00
1 2 50
1 5 00
1 7 50
2 0 00
2 2 50
0 2 00 4 0 0 6 0 0 8 0 0 1 0 00 1 2 0 0
(s e c)
(mV
olt)
20 min
C10
C40Conventional GC
C10 C40
2 min
Ultra Fast GC
QC sample (50 ng/µl)
Column: 5 m x 0.32 mm id, 0.25 µm TR-5Temperature Program:40°C (0.3’), 200°C/min to 350°C (0.5’)Injection volume: 1 µl - splitless
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No more extract re-concentration !
LIQUID EXTRACTION SAMPLE
CLEAN-UP SOLVENT EVAPORATIVE
CONCENTRATION
Ultra Fast GC
ConventionalGC
The sample reconcentration step can be by-passed!
19
ISO 9377-2 (Mod.)
2003: OSPAR proposed a new reference method ISO 9377-2 (Mod.), to get in force from January 2007 in North Sea area
Solvent: n-pentaneRange: C7-C40BTEX have to be separated as well!
Is it still possible to fulfil these specs at high speed of analysis?
YES ! using PTV Injector and Triplus Autosampler
20
Optimized PTV Injector
Split Programmable Temperature Vaporizer (PTV)
• Cool Injection• Prevents in-Needle Discrimination
During Transfer from the Needle to the Injector
• Higher Boiling Point Compounds• Operate PTV independently of
Column at Optimum Cool Temperature for Injection
Permanently Heated Block at Base Avoids Cold Spots for the SampleTransfer to the Column
Sampleevaporationzone
Cold
HotSampletransfer line
21
TriPlus Trio: AS, HS, and SPME
Flexible Sampling Solutions
Standard and Advanced Liquid sampling:
From nano-volumes toLarge Volume techniques(up to 450 µl)
Accurate Headspace sampling:
Zero bench space system based on gas tight syringe approach
SPME (*) technique:
Unprecedented fiber handling robustness to cut sample prep costs
(*) under license from Supelco®
22
TriPlus Technical Overview
• Main Features
- Designed to fully exploit the potentiality of the GC Injectors- AS-HS convertibility;- Easy installation;- Multiple GCs configurations;
• TriPlus AS
• TriPlus HS
• Control software
23
Optimization of Injection : UFGC with ‘Triplus’ Autosampler
Robotic autosampler
• Optimum injection to avoid sample introduction discrimination over wider bp range
• Improved precision
• Cooling of syringe before samplingAvoid losses of light solvents
• Needle solvent Wash technique• Depth of injection control• Injection speed control
24
Ultra Fast GC : PTV Split injection of BTEX in n-Pentane
Column 5m x 0.1 mm id, 0.1 um TR-5
Seconds
20 30 40 50 60 70 80 90 100 110 120 130
Mill
ivol
ts
-250
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
Mill
ivol
ts
-250
0
250
500
750
1000
1250
1500
1750
2000
2250
2500TRACE GC-Channel 1Fluorobenzene + BTEX Mix_New_40C Col tempFluorobenzene + BTEX Mix_New_40C Col temp
NameRetention Time
Ben
zene
Fluo
robe
nzen
e
Tolu
ene
m/p
-Xyl
ene
O-X
ylen
e
Ethy
lben
zene
If the analysis is performed at 40 °C Initial Col Tempa loss of resolution is obtained !
25
Co-solvent addition during injection
Co-solvent addition:
to tune solvent trapping effectto better managing difficult solvents and
difficult solutesto reduce the total amount of solvent
transferred to column and detector
What is a co-solvent ?
A liquid with:
a lower volatility
a different polarity (in some cases)
It is a momentary retention power thatdisappear by evaporation !
26
TriPlus: Software utilities
Needle Solvent wash:selection of solvent vial position and solvent vial depth
27
Co-solvent addition trough the Autosampler syringe during PTVLVI injection at two different liner level
Co-solvent Sample
28
Variation of injection speed and injection level during LVI
Injection speed can be high at the beginning of the
injection and reduced for the rest of the injection
Liner/precolumn conditions are different at the beginning
and during injection
29
PTV-BKF with Co-solvent addition during samplingPAH’s in n-Hexane with iso-Octane
140ul in Hexane only
140ul Hexane+15ul Iso-octane1
2 3 45
6 7
9
8
10
1112 15
14
13 16
12
3 45
6
7 8
910
9
11 12
1314 15
16
31
Ultra Fast GC : PTV Split injection of BTEX in n-Pentane
Column 5m x 0.1 mm id, 0.1 um TR-5
Seconds
20 30 40 50 60 70 80 90 100 110 120 130
Mill
ivol
ts
-250
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
Mill
ivol
ts
-250
0
250
500
750
1000
1250
1500
1750
2000
2250
2500TRACE GC-Channel 1Fluorobenzene + BTEX Mix_New_40C Col tempFluorobenzene + BTEX Mix_New_40C Col temp
NameRetention Time
Ben
zene
Fluo
robe
nzen
e
Tolu
ene
m/p
-Xyl
ene
O-X
ylen
e
Ethy
lben
zene
If the analysis is performed at 40 °C Initial Col Tempa loss of resolution is obtained !
32
Injection and separation of BTEX (10ng/ul) + Fluorobenzene (20ng/ul) in Pentane using the cryo option for the oven
Seconds
80 82 84 86 88 90 92 94 96 98 100 102 104 106 108
Mill
ivol
ts
4000
5000
6000
7000
8000
9000
10000
11000
12000
13000
14000
Mill
ivol
ts
4000
5000
6000
7000
8000
9000
10000
11000
12000
13000
14000
Benz
ene
Fluo
robe
nzen
e
Tolu
ene
Eth
ylbe
nzen
e
m/p
_Xyl
ene
O-X
ylen
e
TRACE GC-Channel 1Fluorobenzene + BTEX Mix_New002_Fluorobenzene and BTEX Mix_New
Name
Column 5m x 0.1 mm id, 0.1 um TR-5
5°C Initial Column Temp
33
Co-Solvent addition applied during PTV injectionPerfect solvent effect for BTEX at 40°C
Seconds
30 35 40 45 50 55 60 65 70 75 80 85 90
Mill
ivol
ts
0
1000
2000
3000
4000
5000
6000
Mill
ivol
ts
0
1000
2000
3000
4000
5000
6000
Be
nzen
e
Fluo
robe
nzen
e
Tolu
ene
Et
hylb
enze
ne
m/p
_Xyl
ene
O
-Xyl
ene
TRACE GC-Channel 1Fluorobenzene + BTEX Mix_New_40C Col temp_2ul with 1 MTBEFluorobenzene + BTEX Mix_New_40C Col temp_2ul with 1 MTBE
Name
1ul of MTBE added to 2 ul of Standard solution in n-Pentane
40°C Initial Column Temperature !
Column 5m x 0.1 mm id, 0.1 um TR-5
34
Standard Mix BTEX and Hydrocarbons
Column: 5 m x 0.1 mm id, 0.1 µm TR-5Temperature Program:38°C (0.8’), 100°C/min to 350°C (0.5’)Injection volume: 3µl – split flow 20ml/min
< 5 min
C40/C20 > 0.9
36
Mix Real Sample and BTEX in PentanePTV injection with Co-solvent (MTBE)
Seconds
0 20 40 60 80 100 120 140 160 180 200
Mill
ivol
ts
0
500
1000
1500
2000
2500
3000
Mill
ivol
ts
0
500
1000
1500
2000
2500
3000
Benz
ene
Fl
uoro
benz
ene
Tol
uene
Et
hylb
enze
nem
/p_X
ylen
e
O
-Xyl
ene
TRACE GC-Channel 12ul Real Sample in Pentane plus 1ul of MTBE002_2ul Real Sample in Pentane plus 1ul of MTBE
Name
Minutes1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90
Mill
ivol
ts
3500
4000
4500
5000
5500
6000
6500
7000
7500
Mill
ivol
ts
3500
4000
4500
5000
5500
6000
6500
7000
7500
B
enze
ne
To
luen
e
E
thyl
benz
ene
m/p
_Xyl
ene
O-X
ylen
e
TRACE GC-Channel 1MIX_ BTEX_Real sample_ in C5_ 5C Col Temp001_MIX_ BTEX_Real sample_ in C5_ 5C Col Temp
Name
Column 5m x 0.1 mm id, 0.1 um TR-5
38
Software: Chrom-Card
A specific application of Chrom-Card allows automatic integration and reporting
• The group peak area C7-C40 is calculated
• The BTEX are individually integrated
Benzene
Toluene
Ethyl-Benzene
m,p-Xylene
o-Xylene
42
Robustness vs dirty matrices
RSD% Group Peak
After 100 real water extract injections is
(10 runs) = 2.3%
Real Water Extract
43
ISO 9377-2 (Mod.): Conventional capillary GC with LVOC Inj
40 min!!!
50µl injected into a pre-column
Ultra Fast analysis is 10-fold more productive !
Large Volume On Column Injection
Automatic OC LV
44
Conclusions
• The analysis of Total Hydrocarbons in water/soil is carriedout by Ultra Fast GC in 10-fold shorter run time, stillmantaining compliance with ISO 9377-2 (Mod.) and otherofficial methods
• The Ultra Fast method allows to:- Maximize productivity- Grant top level of repeatability, sensitivity and ruggedness