Air Monitoring Applications of Selected Ion Flow Tube MS (SIFT-MS)
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SELECTED ION FLOW TUBE MS Basic Principles and Recent Innovations Dr. Joeri Vercammen [email protected]
Transcript of Air Monitoring Applications of Selected Ion Flow Tube MS (SIFT-MS)
SELECTED ION FLOW TUBE MSBasic Principles and Recent Innovations
Dr. Joeri Vercammen
1976First SIFT instrument described by David Smith (UK).
To study the kinetics of ion/molecule reactions in interstellar
clouds.
Low Tk?
Known signals & concentrations of I +, A and P+ are used to calculate reaction rates…
I+ A P+
1996Trace analytical technique.
Calculate concentrations from:
Reaction schemes
k-Values
1997
2001
2014SIFT-MS detects & quantifies trace amounts of volatiles,
Analysis in real time
Volatile organics & inorganics
Low PPB level sensitivity
725
875
900
How does it work?
Precursor ions, generated in-situ
H3O+, NO+, O2+,selected by Q1
Chemical ionisation,Flow tube
Separation & detection of product ions by Q2
Chief characteristics
SIFT-MS has several unique features,
CI with multiple precursor ions results in unique selectivity
Absolute quantification due to thermalized conditions
Designed for ultra-sensitive applications
The possibility of three CI agents increases confidence,
Acetone 59 88 43, 58
Mw 58
Propanal 59 57 57, 58
Mw 58
H3O+ NO+ O2+
Selectivity
Absolute quantification
Analysis time & sample gas flowrate
Reagent and product ion (absolute) signals
Rate coefficient of the reaction
[ 𝐴 ]=¿¿
Ultra-sensitivity
Detection limits in the sub PPB range.
Inert flow path from sample to flow tube
Zero blank levels
No source contamination
Target compounds
Compound Class Compound Class
Alkanes Nitrogen heterocycles
Alkenes and dienes Nitrated organics
Alkynes and diynes Oximes
Aromatic hydrocarbons Nitriles
Terpines Halogenated alkanes and alkenes
Alcohols and diols Halogenated aromatics
Aldehydes and dialdehydes Miscellaneous halogenated organics
Ketones Thiols
Carboxylic acids Thioalcohols
Esters Thioacids
Ethers Thioethers
Cellosolves Sulfur heterocycles
Oxygen heterocycles Sulfoxides
Epoxides Organophosphorus compounds
Amines Inorganics
Amides
Applications
Common applications,
Food & flavour analysis rancidity
Clinical applications, breath analysis
Environmental analysis, real-time air monitoring
Online fermentation monitoring
Rancidity analysis
Exhaled breath analysis
Air monitoring applications
Allergens and their by-products in office air
Emissions from a pilot reactor
Toxic organic compounds in ambient air
Components
Ref. conc. (µg/m³)
Meas. conc. (µg/m³)
St. dev.(µg/m³) %RSD
Limonene 93 93 6.0 6.4%Linalool 155 155 11.5 7.4%
Reproducibility
Component Ref. conc.(µg/m³)
Meas. conc.(µg/m³) Bias Trueness
Limonene 93 93 0% 100%Linalool 155 155 -0.2% 100%
Accuracy
According to EN 15267-3 (AMS).
Performance criteria for automated measuring systems; two times the repeatability at zero, based on 20 analysis.
Sensitivity
Component Blank conc.(µg/m³)
St. dev.(µg/m³)
LOD(µg/m³)
LOQ(µg/m³)
Limonene 9 1.2 2.5 4.9Linalool 9 1.2 2.4 4.8
Uncertainty
Component Bias Reprod. ULimonene 0.04% 6.4% 13%Linalool -0.46% 7.4% 15%
Air freshener emissions in function of ozone concentration
Air monitoring applications
Allergens and their by-products in office air
Emissions from a pilot reactor
Toxic organic compounds in ambient air
Post combustion capture of CO2 uses reversible chemical scrubbing with an appropriate capturing agent.
By-products of the scrubbing process have to be monitored online at PPB levels.
Direct connection
13:40:48 13:55:12 14:09:36 14:24:00 14:38:24 14:52:48 15:07:12 15:21:36 15:36:00 15:50:24 16:04:480
50000
100000
150000
200000
250000
300000
350000
400000
450000
500000
Ammonia (O2+):
20 ppm
5 ppm
Typical results
Air monitoring applications
Allergens and their by-products in office air
Emissions from a pilot reactor
Toxic organic compounds in ambient air
The comparison was made using 25 compounds from the canister method of the United States’ Environmental Protection Agency (US EPA) TO-15 method.
TD-GC/MSIndependent laboratory (ISO/IEC 17025 certified)Three certified gas mixtures
Concentrations calculated from kinetic parameters.
LODs and LOQs for a5-second measurementare typically sub-ppbv.
Typical results
0 20 40 60 80 100 120 140 1600
20
40
60
80
100
120
140
160
Measured GC-MS concentration / ppbv
Mea
sure
d SI
FT-M
S co
ncen
trati
on /
pp
bv
0 10 20 30 40 50 60 700
10
20
30
40
50
60
70
Measured GC-MS concentration / ppbv
Mea
sure
d SI
FT-M
S co
ncen
trati
on /
pp
bv
Aromatic hydrocarbons
Chlorinated hydrocarbons
Comparative analysis using GC-MS and SIFT-MS of four SUMA-type canisters spiked with about 20 compounds at low to mid ppbv levels.
Typical results
SIFT-MS provides unique opportunities to environmental laboratories, researchers, regulators and industry. These include:
Quantitative analysis of a diverse range of compounds without discrimination and with direct comparability to GC-MS.
Ability to monitor pollution and other dynamic events in real-time.
Greatly increased sample throughput for canister and sample bag analysis.
Summary
