Series 2Air ServerThermal DesorptionOptions

Automated canister and on-line air/gas analysis

Series 2Air ServerA range of accessories for series 2UNITY thermal desorbers offeringautomated canister analysis andon-line air/gas monitoring

1. Patent# GB 2395785 (Automated re-collection using a single TD autosampler), 2. Patent# US 6,446,515 B2, 3. Patent# GB 2337513 US 6,564656 B14. Patent# GB 2336649

Thermal desorption technologyThermal desorption (TD) is a highly versatile, sensitiveand labour-saving sample preparation technique for themeasurement of volatile and semi-volatile organiccompounds (VOC and SVOC) in air and materials. It isapplicable to GC-compatible organics ranging involatility from acetylene to n-C40 and a few inorganicgases; including nitrous oxide, SF6, CS2 and H2S. Keyapplications include:

• Environmental and workplace air monitoring

• Civil defence and forensic analysis

• Materials and materials emissions testing

• Food, flavour and fragrance profiling

Many material samples such as drugs, foods, textiles,polymers, paints etc. can be directly thermallydesorbed by weighing them into empty TD sampletubes.

Alternatively, vapours in gas or air can be concentratedon- or off-line onto sorbent traps/tubes before TD-GC(MS) analysis.

Innovation and excellence inthermal desorption Since 1997 Markes International has re-engineeredanalytical thermal desorption for the 21st century.Harnessing unparalleled technical expertise, thecompany has developed a suite of “universal” TDsystems and unique sampling accessories incorporatingkey proprietary innovations such as:

• SecureTD-Q™ and automated sample re-collection using a single TD autosampler1

• RFID tube tagging (TubeTAG™)2

• Diffusion-locking for effective tube sealing androbust automation3

• Innovative low volume valving specificallydesigned for TD4

Many of these innovations now set the standard for TDinstrumentation worldwide.

Introducing the series 2 AirServer rangeSeries 2 Air Server modules add to any series 2(ULTRA-)UNITY system to allow a controlled flow ofwhole-air or gas to be introduced directly into theelectrically-cooled focusing trap of the desorber. Thecombined systems operate cryogen-free (to minimiserunning costs/maintenance) and offer optimumanalytical performance/sensitivity.

With 3- (Air Server) or 8-channel (Canister InterfaceAccessory - CIA 8) options available, method-compliantseries 2 (ULTRA-)UNITY-Air Server systems are suitablefor both automated analysis of canister/bag samplesand round-the-clock unattended monitoring of on-lineair/gas streams.

Key applications include:

• Continuous monitoring of ozone precursors (C2to C10 hydrocarbons) in ambient air and/orvehicle emissions

• On- or off-line odour monitoring e.g. measuringreduced sulphur species such as H2S, mercaptansand sulphides in canister, bags or on-line airstreams at sub- to low-ppb levels

• “Air Toxics” in ambient air e.g. US EPA MethodTO-(14)15

• Industrial process control of gas purity andodour

• Atmospheric research e.g. global backgroundpollution levels, pollution transport and kineticstudies, such as monitoring diurnal changes inurban air pollution or biogenic emission profiles

Series 2 (ULTRA-)UNITY-Air Server systems connect toany Agilent or other brand of GC(MS)

Air Server 2 Main Features• Adds automated canister and on-line air/gas stream analytical capability to any series 2 (ULTRA-)UNITY

thermal desorption (TD) system.

• Cryogen-free operation and low consumption of gas supplies for lower running costs and higher uptime.

• 3 or 8 channel operation for sequencing between sample, zero and standard air/gas streams duringunattended on-line monitoring or automated canister/bag analysis

• Quantitative retention of ultra-volatiles such as acetylene from increased sample volumes (up to 1.5 L)combined with peerless high-resolution capillary chromatographic performance (even under splitless conditions)ensure optimum sensitivity. Parts per trillion (ppt) levels are readily detected.

• Method compliant tube desorption capability included with every system. Can be automated.

• Thermostatted flow path and internal standard addition options for compliance with standard canistermethods.

• Negligible sample carryover plus versatile sampling flows & flexible splitting options allow analysis of bothhigh and low concentration samples.

• Small footprint: Especially useful for installation in mobile labs.

• Versatile water management options for analysis of both dry and humid air/gas samples.

Overview of Air Server operationSeries 2 Air Servers connect to any series 2 UNITY orULTRA-UNITY TD system. They contain 3, or 8 inertsample/stream selection valves uniquely configured toeliminate dead volumes and prevent carryover. Eachwhole air/gas sample (pressurised or at(sub-)atmospheric pressure) is introduced directly intothe electrically-cooled, sorbent-packed, focusing trap ofthe UNITY 2 thermal desorber for a user-specifiedsampling time. Conventional sorbent sampling tubesare not used in this process.

The sampling flow is regulated by an electronic massflow controller (MFC) and optional pump locateddownstream of the trap to eliminate risk ofcontamination. Focusing trap sorbent and trappingtemperatures are selected for quantitative retention ofthe compounds of interest and for selective purging ofpotential interferences such as CO2 and water. Noliquid cryogen is required and only inert, non-emittingcomponents come into contact with the sample. Allsampling parameters are monitored by systemsoftware as an integral part of the analytical method.

At the end of sample introduction, the flow path ispurged with carrier gas to prevent carryover andeliminate oxygen from the focusing trap. The trap thenheats rapidly in a reverse stream of carrier gas toinject/transfer retained compounds into themeasurement system and trigger the analysis. Thistransfer/injection may be performed splitless formaximum sensitivity. (See UNITY 2 brochure formore details.)

Once the focusing trap has desorbed, it cools and re-equilibrates at the trapping temperature. Focusing ofthe next air/gas sample in the sequence may beginwhile analysis of the previous sample is ongoing tooptimise throughput.

Series 2 Air Server rangeThe table below highlights the differences between theAir Server 3 and CIA 8.

Note: Air Server 3 is integrated with UNITY 2 prior toshipment or during field installation to minimize bench space inconfined locations such as mobile labs or remote monitoringstations. The CIA 8 is a separate module.

Air Server 3 Canister InterfaceAccessory (CIA 8)

Number of channels 3 8

Thermostatted flow path

Internal standard addition

Schematic of Air Server 3 operation

Sampleselectionvalves

Series 2Air Server UNITY 2 GC(MS)

Coldtrap

Optionalsplit

Desorptionflow

Samplingflow

Intuitive user interfaceControl of series 2 (ULTRA-)UNITY-Air Server systems(Air Server 3 or CIA 8) is intuitive and integrated withthe UNITY 2 TD software to provide one comprehensiveand easy to understand user interface (UI).

The UI offers a specific mode for on-line/canisteroperation (see figure opposite) and, once selected,users are prompted to enter the relevant samplingparameters such as sampling time, flow rate and purgetimes.

Sequence buildingAutomated sequences for on-line monitoring and/orautomated canister/bag analysis are easily constructedvia the sequence builder. Samples may be assignedindividual desorption methods. Each sample isclassified as sample, calibrant or blank and allsequences may be stored and recalled for futurereference or repeat use.

Graphical sequence viewerThe sequence viewer presents a clear graphical displayof current sequence status.

Sequence reporting Information associated with each analysis, such as thetime, date and any deviations, are all recorded in thesequence reporter. Any sample sequence failuretriggers the GC(MS) system to start a blank run tokeep the analyser in step with the autosampler.

Up to 8-channels foroptimum throughput

Control method screen (top) of user interface.Complete user interface screen (bottom)

Round-the-clock,cryogen-free monitoring

On-line operationOn-line monitoring systems typically comprise aseries 2 UNITY with integrated 3-channel Air Servermodule. The combined system is programmed torepeatedly introduce air/gas from the samplestream(s) and to automatically sequence calibrationgas and zero air/gas at user-defined frequencies,typically once every 24 hours. Sequences may berecycled indefinitely to minimise system programming.

Continuous monitoring of ozone precursors (C2 –C10 hydrocarbons) in urban air, as required by bothEuropean and US regulations1,2, is a key application forseries 2 UNITY-Air Server systems.

Key advantages of Markes series 2 UNITY-Air Serversystems for ozone precursor monitoring include:

• Unattended operation for extended periods:Cryogen-free operation and low consumption ofgases simplifies installation in mobile labs andoffers extended periods of unattended operationin remote field monitoring stations. Markescryogen-free series 2 UNITY-Air Server systemsconsume only 40 ml/min dry gas/air whenconfigured without a Nafion dryer and less than200 ml/min when a dryer is configured. This isbetween 3 and 10 times less than other cryogen-free ozone precursor monitoring systems andallows extended operation without cylinderreplacement

• Sensitivity: Quantitative retention of ultra-volatiles such as acetylene from up to 1.5 L airsample volumes combined with efficient splitlessdesorption at low (<2 ml/min) flows ensures bestpossible detection limits (typically 1-50 pptlevels)

1. Council Directive 96/62/EC: On ambient air quality assessment andmanagement, and the daughter directive - 2002/3/EC relating to ozone inambient air

2. 1990 US Clean Air Act Ammendment

Splitless desorption of 56-compound US EPA mix of ozone precursors using series 2 UNITY-AirServer 3 with dual column/dual FID GC with Dean’s switch

CompoundDet limit

(ppb)450 mlsample

Column%RSD

(n=12) Rt450 mlsample

% RSD(n=12)

peak area450 mlsample

Ethane 0.026 Al PLOT 0.07 0.3Butane 0.010 Al PLOT 0.01 0.4Hexane 0.019 DB1 0.01 0.5Octane 0.017 DB1 0.01 1.0

Data courtesy of Ecole des Mines deDouai, France

• Reliably excellent chromatographicperformance: Great resolution, stable retentiontimes and repeatable concentration data minimisemeasurement uncertainty and simplify datainterpretation/validation

• Small footprint: The Series 2 UNITY withintegrated 3-channel Air Server is only 22 cm(9-inches) wide

Timed startSeries 2 UNITY-Air Server systems allow the start of amonitoring sequence to be programmed for a specificdate and time (e.g. noon on Monday May 1st) and forthe period between each sampling cycle to be fixed.The sampling cycle used for ozone precursormonitoring for example, is typically 1 hour. In this caseair is usually sampled into the UNITY 2 focusing trapfor 40 minutes of every hour starting on the hour.

Cryogen-free trapping of ultra-volatile compoundsincluding acetylene (ethyne) from up to 1.5 L of air

Field-proven, robust on-line monitoring of H2S and other reduced sulphur compounds downto sub-ppb levels in ambient air

On-line odour monitoring - Another key application for series 2 UNITY with integrated Air Server 3 option

y = 0.2953x + 5.2249R2 = 0.9999

Sample Volume (mL)

Acet

ylene

Pea

k Ar

ea

H 2S

CH3S

H

DMS

DMDS

H 2S

CH3S

H

DMS

DMDS

10 ppb

20 ppbCompound

MinimumDetection

Limit (ppb)%RSD(n=10,20ppb)

Hydrogen sulphide(H2S) 0.15 4.1

Methyl mercaptan(CH3SH) 0.15 1.8

Dimethyl sulphide(C2H6S) 0.15 0.8

Dimethyl disulphide(C2H6S2) 0.10 0.8

Data courtesy of Ecole des Mines deDouai, France

Data courtesy of ITC, South Korea

Automated off-line analysis ofcanister/bag samplesKey issues associated with automated canister analysisinclude throughput, running costs, sensitivity, watermanagement and method compliance. A typical AirServer system configuration in this case would include:The series 2 (ULTRA-)UNITY with a Canister InterfaceAccessory (CIA 8) for 8 channels.

Series 2 UNITY with CIA 8 features a thermostattedsample flow path and internal standard (IS)addition to the focusing trap. The system is fullycompliant with relevant standard methods such asUS EPA Method TO-15 for “Air Toxics”.

Air toxics monitoring

Key advantages of Markes series 2 (ULTRA-)UNITY-CIA 8 technology for Air Toxics monitoring and forcanister air analysis generally include:

• Productivity: Markes systems offer 8-channelsfor automated operation over extended periods.Confirmatory repeat analysis of each canistermay be included in the automation sequence

• Cost reduction. Cryogen-free operationminimises:

• Capital costs (no liquid nitrogen dewarrequired)

• Running costs (cryo-cooled systems requirefresh supplies of liquid coolant as often asevery 2 or 3 days)

• Manpower (changing/refilling of liquidcoolant dewars takes time and effort)

• Downtime (replenishing liquid cryogen ofteninterrupts an automated sequence)

Cryogen-free operation savesthousands of dollars a month...

Schematic of series 2 UNITY - CIA 8 operationVersatile sample splitting options offer compatibilitywith vapour concentrations ranging from ppt to ppm

CIA 8

Streamselection

Internalstandardaddition

Samples Internalstandard

Samplingflow

Desorptionflow

UNITY

GCMS

Optional split

TO-15 standard chromatogram (1ppb in 1 L) (main) and real air sample (insert)

Canisters, bags and sorbent tubes

1

2

34

5

67

8

9

1011 12

13

14

16

15 17 18

19

20

2122

23

24

25

26

27

28

29

30

31

32

33

34 35

36

3738 39

40 41

1 Dichlorodifluoromethane2 1,2–Dichlorotetrafluoroethane3 1,3–Butadiene4 Trichlorofluoromethane5 1,1,2–Trichlorotrifluoroethane

(Freon 113)6 Isopropyl alcohol 7 Carbon disulfide8 Methylene chloride9 Tert-butyl methyl ether10 n-Hexane11 1,1-Dichloroethane12 Ethyl acetate, methyl ethyl ketone13 Tetrahydrofuran

14 Cyclohexane15 Benzene16 n-Heptane17 Trichloroethylene18 1,2–Dichloropropane19 Bromodichloromethane20 Trans-1,3-dichloropropene21 Methyl isobutyl ketone22 Toluene23 Cis-1,3-Dichloropropene24 Tetrachloroethylene25 Methyl n-butyl ketone26 Dibromochloromethane27 1,2–Dibromoethane

28 Chlorobenzene29 Ethylbenzene30 Xylene31 Styrene32 Tribromomethane33 1,1,2,2-Tetrachloroethane34 1,2,4-Trimethylbenzene35 1,3,5-Trimethylbenzene36 1,2-Dichlorobenzene37 1,3-Dichlorobenzene38 Chloromethylbenzene (alpha)39 1,4–Dichlorobenzene40 1,2,4–Trichlorobenzene41 Hexachloro-1,3-butadiene

Isopr

opyl

alcoh

ol DCM

Hexa

ne

Meth

yl cy

clope

ntan

e

Cyclo

hexa

ne

1-Me

thylo

xy-2

-pro

pano

l

Tolue

ne2-Me

thyl

buta

ne

Benz

ene

2,4-

Dime

thyl

pent

ane

0.1 ppb level

Time (mins)

• Analytical excellence: Super-efficient trapdesorption and reliably excellent chromatographicperformance, even under splitless conditions andwithout on-column focusing (see Series 2 UNITYbrochure), optimise sensitivity and simplifyidentification of target air toxic analytes even incomplex backgrounds.

• Versatile water management: Markes TDsystems offer selective purging of water,sophisticated sample splitting and the option ofin-line dryers for effective water managementunder any air monitoring conditions.

ppm...ppb...ppt

Versatility

The application range of series 2 AirServer technologySeries 2 (ULTRA-)UNITY–Air Server systems (Air Server3 or CIA 8) offer quantitative and cryogen-freeretention, even of ultra-volatile species such as freonsand C2 hydrocarbons, together with complete recoveryacross the air toxics boiling range. Labile, odorousanalytes, such as H2S and mercaptans may also bemeasured at sub-ppb concentrations. Markes systemsare compatible with the highest boiling compounds thatcan be recovered from canisters or ambienttemperature air/gas streams.

New improved stream selection valves and an inert,thermostatted flow path eliminate sample carryovereven when monitoring over a wide concentration range(ppt to ppm). This allows ambient air samples to becalibrated with small volumes of relatively concentratedstandard gas. It also allows automated sequencing ofsamples varying widely in concentration without fear ofcontamination.

Compatibility with samples over a wide concentrationrange is further enhanced by sophisticated,electronically-controlled sample splitting during trapdesorption (and during tube desorption, if applicable).

On-line monitoring, canisters/bagsAND tube desorptionWhether they are used for on-line monitoring or off-line canister/bag analysis, all systems incorporatingseries 2 Air Server technology, offer complementarytube desorption.

Every series 2 Air Server is connected to a Markes(ULTRA-)UNITY 2 system. The UNITY 2 TD platformoffers method-compliant desorption of single tubes andthe addition of a series 2 ULTRA allows automaticanalysis of up to 100 sorbent tubes. Series 2 (ULTRA-)UNITY systems are described in detail in the associatedbrochures and their performance is not compromised inany way by the addition of an Air Server module.

In summary, key advantages of series 2 (ULTRA-)UNITYsystems for tube desorption include:

• Application versatility. Series 2 (ULTRA-)UNITYsystems are compatible with every TD applicationon one analytical platform; ultra-volatiles (e.g. C2hydrocarbons), semi-volatiles (up to n-C40) andreactive compounds. Samples for tube desorptioneither comprise sorbent tubes used to collectorganic vapours or material samples (solid orliquid) weighed directly into empty TD sampletubes for direct desorption. Splitless, single ordouble split options allow analysis of samplesranging in concentration from ppt to percentwithout overloading the analytical system

• Method compliance. Markes’ tube desorptiontechnology complies with all key standardmethods; US EPA Method TO-17 (ambient andindoor air), ISO 16017 (workplace, ambient andindoor air), EN ISO 16000 (materials emissiontesting), NIOSH 2549 (workplace indoor air), etc.Important features for method compliance includeeffective tube sealing during automation,stringent (ambient-temperature/no-flow) leaktesting, cryogen-free cooling and the option of ISaddition

Detection of trace level analytes aids atmosphericresearch

Real time monitoring -real time detection

30 ml of air from bubbles in the ice corecollected in canisters. Analysis by TD-GC-MS in NCI mode. Unit ppt detection limitsTo

luene Subsequent blank run

Contaminated air sample

Negligible carryover with series 2 UNITY-Air Server

• Repeat analysis. The proprietary SecureTD-Qfacility is supplied as standard with every series 2(ULTRA-)UNITY system. It offers quantitative re-collection of any split flow (during tube or trapdesorption) facilitating repeat analysis andsimplifying method/data validation. SecureTD-Qovercomes the one-shot limitation of otherthermal desorbers

• High throughput. 100-tube capacity andoverlap mode (the ability to begin desorption of asubsequent sample while analysis of a previoussample is ongoing) optimise productivity/revenuegeneration

• Compatibility with RFID tagged tubes(TubeTAG) for enhanced tube/sampletraceability

TrademarksSecureTD-Q™ and TubeTAG™ are trademarks ofMarkes International Ltd.

Markes International Ltd.Gwaun Elai Medi Science Campus

LlantrisantRCT

CF72 8XLUnited Kingdom

T: +44 (0)1443 230935 F: +44 (0)1443 231531E: enquiries@markes.com W: www.markes.com