Gas Chromatography -Ion Mobility Spectrometry (GC-IMS ... · Gas Chromatography -Ion Mobility...

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Gas Chromatography - Ion Mobility Spectrometry (GC-IMS) - Trace Gas Analysis of Volatiles in various Applications by G.A.S. Gesellschaft für analytische Sensorsysteme mbH Dortmund - Webinar 2.4.2019

Transcript of Gas Chromatography -Ion Mobility Spectrometry (GC-IMS ... · Gas Chromatography -Ion Mobility...

Gas Chromatography - Ion Mobility Spectrometry (GC-IMS)

-

Trace Gas Analysis of Volatiles in various Applications

by

G.A.S. Gesellschaft für analytische Sensorsysteme mbH

Dortmund - Webinar2.4.2019

Company:

▪ Founded in 1997 as spin-off of the ISAS –Leibniz-Institute for Analytical Sciences e.V.

▪ R&D and manufacturing facilities atTechnologyCentre Dortmund

▪ Interdisciplinary team (17 employees)consisting of chemists, physicists, machin-ery/electrical and computer engineers

▪ Development, production and distribution ofanalytical instruments based on GasChromatography coupled to Ion MobilitySpectrometry customized to application and customer requirements

▪ More than 200 installed instrumentsat global market leaders in food &flavours, process industry, researchinstitutes

▪ since 09/2018 VAR of Agilent Technologies

G.A.S. – Gesellschaft für analytische Sensorsysteme mbH

G.A.S. – What we do…?

GC-IMS BreathSpec® FlavourSpec®

Detection of VOCs in gases

Detection of traces of VOCs

in exhaled human breath

Detection of traces of VOCs in the

headspace of solid, liquid samples in food

Applications

Siloxanes in biogasFilter breakthrough

Odorants in Natural GasesBad smell from Industry

Applications

Marker compounds in human breath

MAC-Monitoring

Applications

QC of raw material, semi-finished and end-products

(Off-) Flavour analysisShelf life…

Trace gas Analysis in dedicated civilian Application

Overview: G.A.S.’ main Markets and Applications

Time-Of-Flight (TOF-) IMS made by G.A.S

Driftgas inlet

Ionisation region

Drift region

Faraday plate

Outlet

Sample Inlet

Electrical field

Shutter

+

++

++

++

+

+

IMS Drift Tube

Working Principle of IMS – Formation of Charged Analytes

Tritium Source

- Ionization of water molecules from operation gas by ß-radiation - Analytes are ionised due to collisions with positively charged proton clusters, which form a positively charged analyte-water-cluster-complex

Driftgas inlet

Ionisation region

Drift region

Faraday plate

Outlet

Sample Inlet

Electrical field

Shutter

+

++

++

++

+

+

IMS Drift Tube

Working Principle of IMS – Formation of Charged Analytes

Tritium Source

Sample neutral Reactant ion Cluster ionProduct ionProtonated monomer Water

Driftgas inlet

Ionisation region

Drift region

Faraday plate

Outlet

Sample Inlet

Electrical field

Shutter

IMS Drift Tube

Working Principle of IMS – Separation of Analytes

Tritium Source +

+++

+

+

+

+

+

+

+

+

- Analytes are kept (ion-trap) in ion chamber and pushed into the drift tube - driftgas molecules enter the drift tube from opposite site- Collisions between analyte and drift gas molecules

Driftgas inlet

Ionisation region

Drift region

Faraday plate

Outlet

Sample Inlet

Electrical field

Shutter

IMS Drift Tube

Tritium Source +

++

+

++

+

+

+

Sig

nal

Drift time / ms

+

+

+

+

Working Principle of IMS – Separation of Analytes

- Analytes are separated in a lowelectrical field based on theirphysical parameters (µ, CCS)

- Determined value: Drift time, tD

Driftgas inlet

Ionisation region

Drift region

Faraday plate

Outlet

Sample Inlet

Electrical field

Shutter

IMS Drift Tube

Tritium Source

+

+

+

Sig

nal

Drift time / ms

+ + +

- Analytes are separated in a lowelectrical field based on theirphysical parameters (µ, CCS)

- Determined value: Drift time, tD

Working Principle of IMS – Separation of Analytes

Driftgas inlet

Ionisation region

Drift region

Faraday plate

Outlet

Sample Inlet

Electrical field

Shutter

IMS Drift Tube

Tritium Source

+

+

+

Theoretical Principle of the IMS – Ion Mobility K

µ = reduced mass of ion / drift gas molecule

k = Boltzmann constantT = Temperature of drift gasQ = Ion chargen = drift gas number densityσ = Collision cross section of the ion

RIP(H2O)nH+

HexanoneMonomer

MH+

HexanoneDimerM2H+

5 ppb

16 ppb

49 ppb

Quantitative information

frompeak intensity

Qualitative information

frompeak position

IMS Resolution: ~ 100

Calibration for 2-Hexanone

Peak Analysis (Height, Volume) for Quantification

+ Water (NH3, NO) +H2O

Ionisation driftgas

Creation of reaction ions

(H2O)xH+, (H2O)yNO+, (H2O)zNH4+ + e-

− − + −+ → + +N N e2 2

'

(Nitrogen)

positve negative

Positive analyt ions

• Proton transfer(H2O)xH++ A → AH+ + xH2O

• Charge transfer(H2O)yNO+ + A → A+ + NO + yH2O

• Nucleophilic attachment(H2O)yNO+ + A → ANO+ + yH2O

Negative analyt ions

• Associative electron captureAB + e- → AB-

• Dissociative electron captureAB + e- → A + B-

• Proton abstractionABH + (H2O)nO2

- → AB- + nH2O + HO2

Ionisation Mechanism

Soft-Ionization and Ambient pressure – reasons for outstanding Sensitivity!

Aromatic Amines 930.0 KJ/mol Pyridine

Amines 899.0 KJ/mol Methyl Amine

Phosphorous Compounds 890.6 KJ/mol Trimethylphosphate

Sulfoxides 884.4 KJ/mol Dimethyl Sulfoxide

853.6 KJ/mol Ammonia

Ketones 832.7 KJ/mol 2-Pentanone

Esters 821.6 KJ/mol Methyl Acetate

Alkenes 805.2 KJ/mol 1-Hexene

Alcohols 789.2 KJ/mol Butanol

Aromatics 750.4 KJ/mol Benzene

691.0 KJ/mol WaterAlkanes 543.5 KJ/mol Methane

Source: Gary Eiceman & Zeev Karpas, Ion Mobility Spectrometry, CRC Press, 2005, ISBN 0-8493-2247-2

Protone affinities of various VOCs can be found at the NIST chemistry webbookhttp://webbook.nist.gov/chemistry/

Pro

ton

e A

ffin

itie

s

Proton Affinities of VOCs

fast GCpre-separation

(typically 1 to 15 min)

IMS separation (30 ms)

IMS separation

Synergy of Selectivity through GC separation matched with Sensitivity of IMS!

Application in complex Matrices require a GC-separation

pseudo-colour representationIMS chromatogram

3DIMS chromatogram

SingleIMS spectraIM

S s

igna

l

IMS drift time

2-Dimensional separation by GC and IMS

Full GC-IMS headspace analysis

Analytical evaluation

VOCal - GC-IMS Data Analysis -

• Visualisation

• Organisation of measurement data

• List of experimental conditions

• Data analysis:

• compound calibration → quantification

• compound identification → comp. Libary

• Data export (csv, excel, rapid miner, etc….)

• Reporting

Customized Software

e.g. BeerAnalyzer

• reduced/application

based functionalities

• easy and reliable

operation at-line:

• data acquisition

• calibration

• reporting

Inhouse Software secures maximum Output and Flexibility

PlugIn Modules

VOCal – Data Analysis PC-Software

Flexible and user-friendly Interface for 3-D Data Analysis

Conditions: Room temperature, no-salt-added, 10min sampling

Geosmin: Total-Ion-Current Chromatograms 0-50ppt

5 ppt

50 ppt

Geosmin was pre-concentrated using a thermodesorber unit

Calibration (TIC Maximum vs. Geosmin ng/L)

Specific Compounds can be extracted for Data Analysis

→ Mark compounds/signals of interest

→ Signals are “extracted” and plotted

Single Compounds in Measurements are tracked/followed

▪ Gallery Plot enables easy and fast comparison of different

samples▪ Differences in concentrations

or presence/absence of marker signals can be easily

seen

NIST-based GC-RI indices plus IMS drift times allow high Certainty!

‚GCxIMS Library Search‘ for Compound Identification

Gas Chromatograhy-Ion Mobility Spectrometer (GC-IMS)

Trace analysis of volatiles in Food and Flavourby

G.A.S. Gesellschaft für analytische Sensorsysteme mbH

Product Quality Control in Food & Flavour Industry

Specific compounds Authentication

Quality Control Differentiation

Classification

- static headspace analysis

- automated sample handling- solid / liquid / gaseous samples (HS)- no sample pretreatment necessary

FEATURES

R&D / Product Quality Control: FlavourSpec®

2005: UCO – G.A.S. start Cooperation in Food/Agro Field

Improvements on G.A.S.’ systems lead to success of GC-IMS in new Applications

Niche for GC-IMS in different Applications of QC

Hedonistic EvaluationHigh-end Mass Spec GC-IMS

- ‘golden standard‘

- approved technology

- R&D

- available data base

- well known

- most decissive Criteria

- availability critical

- subjectivity problematic

- easy-to-use

- reliabe (phys. principle)

- QC related

- fingerprint and data base

- attractive value for money

- flexible/portable use

Workflow of the FlavourSpec® headspace Analysis

Fill vialGenerate headspace

Sampling

FlavourSpec®

Injection Data Analyis

Headspace sampling

Long runtimes for complex mixtures

Well developed technology

Limited sensitivity

Detectortime

Gas Chromatography – Conventional Detector

Second physical separation

Outstanding sensitivity

High GC mapping by fast spectrometry

time

IMS

Gas Chromatography – Ion Mobility Spectrometry

Process Control in Brewing: Analysis of vicinal Diketones

Quantification of Diacetyl/Pentanedione in the headspace determines end of Brewing

Diacetyle

Pentanedione

Ethanol

IMS signal

IMS drift time / ms

Diacetyl/Pentandione are known markers related to brewing (butterscotch flavour).

Their measurement lies in the range of 0 and 250 µg/L.

Determination is a worldwide standard in larger breweries.

Conventional GC systems use ECD as detector (radioactive source).

Process Control in Brewing: Analysis of vicinal Diketones

FlavourSpec plus customized BeerAnalyzer software is a very attractive Alternative

Gallery plot of selected evaluation areas

Significant rise of peak intensities of e.g. various Aldehydes with exposure times!

0days

7days

14days

21days

Increasin

g A

ge

UHT Milk: Storage Time effects on VOC Composition

Substance Identification

Ageing of Wine: Monitored by effects on VOC Composition

2018 (6 months old)

2017(18 months old)

2016(30 months old)

2014(54 months old)

Compounds in NZ Sauvignon Blanc

increasing with age (34)

Compounds in NZ Sauvignon Blanc

decreasing with age (31)

FlavourSpec - Monitoring Increase and Decrease of flavor inducing Volatiles !

Outgasing from Packaging Material

Packaging Type is differentiated by outgasing Marker Compounds/Volatiles !

37

Criteria GC-MS FlavourSpec1.

An

alyt

ical

asp

ects

Selectivity Excellent selectivity for broad range of analytical tasks

High level of selectivity due to 2-dimensional separation (GC and IMS). By that availability of a true orthogonality (like GCxGC) with

regard to separation capacity to separate even co-eluting compounds

Sensitivity Good, but -depending on application - might need to pre-concentrate to reach

low ppb-range. Besides CI configuration and operation in single ion mode needed

Outstanding sensitivity (low ppb) without pre-concentration -sampling 'as is'

Sample pre-treatment

Needed for several applications to reach level of odour thresholds

Not needed

Data base Available, related to NIST data baseFully established state-of-the-art technology -

analytical benchmark

GC-retention indices of NIST plus IMS drift times for approx. 150 compounds available (editable).Customized libraries possible.

Information Structure information with average benifit as EI spectra often not clearly interpretable.

Chemometric fingerprinting limited often due to strong interference of analyte signals and

background.

Identification of unknown compounds through NIST retention index and IMS drift times

Identification confirmed by pure compounds (permeation tubes) if requested

Quick decissions based on VOC-pattern ('fingerprint') and/or intensities of single compounds

Run times - Sample throughput

Rather laborous and time consuming (depending on user's experience) - run times

significantly beyond 15 minutes

High sample throughput depending on selected GC column.Run times of 10-20 minutes inject-to-inject allowing to test for >100

samples per dayData analysis Automated data analysis available for most systems After development of analytical method: Automated data processing and

result interpretationBenifits from

systemData base can be fed with user's spectra Learning system - regular use will improve results and ease operation

New compounds can be added to libraryIntervalls Depending on use, rather maintenance intensive -

besides source cleaning approx. every 200 - 500measurements, depending on sample complexity.

Regular maintenance of vacuum pump needed

Routine check-ups every 24 month. Besides only minor maintenance (septum change, syringe

change, automated backing out)

2. Economicaspects

Investment costs Depending on configuration approx. 75-150 K€ 60 K€

Consumables Helium (approx. 50 €/month) Lab supply or nitrogen from cylinder 40-60 €/month

Use of nitrogen/air generator possible - available at G.A.S.Maintenance and

other costs4,000-5,000 €/year

Vacuum pump 10,000 € every 5 years

2,000 € every 24 month (1,000/year)

3. Other aspects

Vacuum pump Noisy for lab personnel No pump

Portability Pure lab instruments Semi-portable, can operate within lab or at production line and be easily moved to other location

Readiness/warm-up time <1 hours

Benchmark of GC-MS vs. FlavourSpec

FlavourSpec Application Summary in Categories

• Process control:

1. Beer: Precise quantification (range:10-50µg/L) of VDK (diactyl & pentanedione) during brewing

2. Washing agents: Replace sensory panels regarding Off-smell of semi-finished products

3. Bottling lines: Purity of soft drink manufacturing hoses

• Product authentication

1. Quality determination of olive oil (L, V, EV)

2. High priced destillates from frauds

3. Cigarette counterfeit detection

• Impartial proof of flavours/Flavour documentation

1. Support of sensory panels regarding critical samples via VOC-fingerprint/marker compounds

2. Support of sensory panels during blending

• Quality control

1. Raw material sourcing with regard to flavour quality

2. Overcome limited access of sensory panels/achieve 100% finished product QC procedures

3. Shelf life and storage conditions of foodstuff same as of beverages

4. Sensitive off-flavour detection from packaging on foodstuff (cap liner, ink, etc)

5. Replacement of bisphenol A on flavour compounds of beverages

• ... List of applications/feasibility study separately provided

Innovative Flavour Measurement using GC-IMS

• GC-IMS (Gas chromatograph coupled to Ion Mobility Spectrometer)

– Separation by GC

– Separation/Detection via IMS at very low (ppb) level

• Characteristics:

– Appropriate for the routines in a QC-laboratory or “at line”

– No sample pre-treatment

– Automatic data analysis

– “Portable”, no helium required

– Fast cycle times (inject-to-inject: <15 minutes)

– Low operational costs (< 75 €/month)

39

Gas Chromatograph

BreathSpec®: Measurement of Volatiles in Human Breath

Ion-Mobility-Spectrometer

-

Breath Sampling via heated line Breath Samplingvia syringe

Sampling Options

breath DSafter smoking

breath DS

Intoxication: Smoking

One minute after smoking a significant number of volatile compounds (VOC) can be detected.Source of VOCs is mainly pyrolysis, e.g. acroleins, ketones, aldehydes etc.)

GC

Run

time

/ sec

IMS Drift Time / RIPrel.

BreathSpec® - Application Summary

• Intoxication:

1. Alcoholic poisoning methanol/ethanol (Horizon2020 project)

2. Working place related exposure control of TICs

• Medical Research

1. Marker compounds as indicators for diseases (acetone, amonia)

2. Oxidative stress of astronautes after sky walks (project with airbus DS)

• Monitoring of anaesthetic gases

1. Dosing of ketamine in intensive care (G.A.S. project application)

• Pharmacokinetics

1. Drug efficiency/dosing

... List of applications/feasibility study separately provided

Source: www.ciggyfree.com

GC-IMS – Technology Platform

Device Plan

G.A.S. Customized Solutions

GC-IMS in Various other Applications

Quality Control of Solvents (DME)

Siloxanes in Digestion Gas/Biogas

Outgasing from sample bags

Detection of TICs forWorking Place

Monitoring

Portable Quantification of Odorants in natural gas

On-line Monitoring of Odorants in natural gas

Power Supply

GC-IMS Set-Up at-site

GC-IMSMeasurement System

Gas Generator

Sampling via internal pump of the device

Data transfer via:LAN cable, current loop, Modbus, USB

Control room

Results, Quantifcation

at-site

Petro-Chemical / Environmental Applications:BTX – Quantification - Calibration

0 ppb25 ppb

60 ppb

150 ppb

Measurements of Benzene, Toluene and o-Xylene in the range of 0 → 500 ppb

LOD (o-Xylene) = ~10 ppb

LOD (Toluene, Benzene) = ~25 ppb

o-Xylene

Toluene

Benzene

49

5 ppb DMS

IMS spectra of DMS (5 to 140 ppb).

• Methylating agent in pharma industry• Toxic, cancerogenic

➢ Online monitoring of chemical facilities (working places) needed

➢ Detection limit of DMS: ~200 ppt

Chemical Industry: Detection of Dimethyl Sulfate DMS

Instrument screen while measuring.

GC-IMS: Monitoring of DMS in Chemical Facilities

Integrated into a process measuring and control system

of Bilfinger Maintenance GmbH, Frankfurt a.M.

57ppb

12ppb

1ppm

H2S COS

• Measurements of Hydrogen sulfide and Carbonyl sulfide• Concentration range 12ppb – 1ppm

• LOD (H2S) <10 ppb• LOD (COS) ~10 ppb

Petrochemistry, Hydrodesulfurization / Chemical Industry:Hydrogen sulfide H2S / Carbonyl sulfide COS

25 ppb

0ppb10 ppb

25 ppb50 ppb

100 ppb

1000 ppb

Continuous at-site measurements every 90 sec

→ no hysteresis

Petrochemistry, Environmental:Nitric Oxide (NO) in Ethene

GC-IMS Data Analyis

GC-IMS for Dimethylsulfate and Isocyanate Monitoring

Control Room

Different sources forgaseous samples…

Gases

Gas nets

Working Places

Emissions

Data/Result transfer

Continuous MonitoringSample bags

Sampling

Self Check and Fault Detection for Industrial Applications

Industrial application: Filter load/efficiency/breakthrough

Out Out Out

Time

In In In

1. Beginning offilling

Diagram:Concen-tration inair

2. Absorption process ofcarbon filter

3. Filter Breakthrough

CarbonFilter

GC-IMS on-site: Filter Load/Efficiency/Breakthrough Testing

GC-IMS

Sensitive, rugged and easy to use on-site Tool !

HVC, Alkmaar, NL

Circular Gas Flow Unit (CGFU) – from 10/2015 onwards

GC-IMS

City of Madrid: Off-smell from waste plants due to saturated Filters!

Odournet S.L.-project: Madrid

…enables further on-site Applications!

VOC-Emissions from Indoor Car Surfaces at ppb-Level

China: Analytical Assignment Car Application

Detection & quantification of compounds in below standing concentration/limits:

Compound Requested Limit / ppb

Benzene 19

Toluene 27

o-, m-, p-Xylene 231

Ethylbenzene 231

Styrene 61

Formaldehyde 82

Acetaldehyde 111

Acrolein 22

Aromatic hydrocarbons

Aldehydes

5

1

43

21 Thermodesorber

2 TENAX TA Tube slot

3 Heated Sample Line

4 Heated Transfer Line

5 GC-IMS with internal loop and touch-screen

6 Interlink (Trigger)

6

G.A.S.-Solution: Setup and Working Principle

• Thermodesorber

•manages all sampling (and self-cleaning) steps

•handles measurements cycles (‘master’ mode)

•periodical measurements possible

• GC-IMS

•acts in ‘slave’ mode

•Trigger initiates measurement program

•suction of enriched sample gas

•injection to gas chromatographic column

Analyzer set-up works stand-alone, no PC is required for routine analysis!

Gallery Plot of the VOCs of ‘Chinese Car Industry‘

No CompoundLimit / ppb

Suggested Detection Set-Up

1 Acetaldehyde 111 GC-IMS

2 Acrolein 22 GC-IMS or µTD-GC-IMS

3 Benzene 19 µTD-GC-IMS

4 Toluene 27 µTD-GC-IMS

5 Ethylbenzene 231 GC-IMS or µTD-GC-IMS

6,7,8 p-, m-, o-Xylene 231GC-IMS or µTD-GC-IMS

9 Styrene 61 GC-IMS or µTD-GC-IMS

0ppb10ppb50ppb

100ppb200ppb312ppb

0ppb5ppb

20ppb50ppb

100ppb

GC

-IM

SµT

D-G

C-I

MS

Using GC-IMS technology alone and in combination with the µTD enables detection of

all desired compounds in the desired concentration range (s. table) except Formaldehyde

GC-IMS: Readings on instrument Display

15 Minutes Cicle Time

GC-IMS: Application Acetaldehyde

Detection limit <5ppb using GC-IMS without sample Pre-Treatment!

GC-IMS: Application Summary

• Process control:

1. Filter load/efficiency/breakthrough in biogas plants

2. Quality control of landfill gas w.r.t. concentrations of siloxanes/total silica

3. Clean room/FAP monitoring during wafer production

4. VOC-Emissions in car indoors

• Personal care

1. Flavour development from cosmetic products

2. Perfume twins/dupes

• Environment

1. Bad smell from industrial plants via fingerprint/marker compounds

2. Working Place control/MAC monitoring

• Natural gas

1. Odorants Gasodor-S-Free/THT/TBM in natural gas

2. Traces (<1ppm) of H2S, COS and light mercaptanes – under investigation

... List of applications/feasibility study separately provided

2018: Ion Mobility Spectrometer for Benchtop GCs

*Coupling available for Agilent GCs 6890/7890B and Shimadzu GC-2010 Plus

ADVANTAGES

• Sensitive: Detection limits in the low ppbv

(µg/m3) range for VOCs with heteroatomslike ketones, aldehyds, alcohols, amines orhalogenated and sulphurous compounds

• Selective due to specific analyte ion drifttimes (2 dimensional separation, fullorthogonality)

• Flexible: Positive and negative iongeneration

• High GC sampling frequency

• No licence for 3H source requiredaccording to EU directive 96/29 EURATOM

• High reproducibility

• Operation with nitrogen or synthetic air

• Atmospheric Pressure Ionisation (API)

• Stand alone data aquisition software andsoftware suite for 3D GC-IMS data analysis

• No need for a radiation protection officer

2019: Integration of IMS into µGC490 of Agilent

Gas Chromatograph - Thermo Conductivity Detector - Ion Mobility Spectrometer

Unique Solution for industrial Applications in one Instrument!

ADVANTAGES

• Sensitive: Detection limits in the low ppbv

(µg/m3) range for VOCs with heteroatomslike ketones, aldehyds, alcohols, amines orhalogenated and sulphurous compounds

• Flexible: Positive and negative iongeneration

• High GC sampling frequency

• No licence for 3H source requiredaccording to EU directive 96/29 EURATOM

• High reproducibility

• Operation with nitrogen or synthetic air

• Atmospheric Pressure Ionisation (API)

• No need for a radiation protection officer

Thank you for your attention!

For further questions please

contact

G.A.S. mbH Gesellschaft für analytische Sensorsysteme mbHOtto-Hahn Str. 1544227 Dortmund

+49 231 [email protected]