igc brochure 2002

8/7/2019 IGC brochure 2002

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The world’s most advanced

INVERSE GAS CHROMATOGRAPH

GC



CONTROL PC

Packed sample

Column

Probe gas andhumidifiermodule

Flowswitchingmodule Column

moduleDetectormodules

FID

TCD

Carrier gases

Flow

controlmodule

PROBE GAS OVEN COLUMN OVEN

SMS i GC SCHEMATIC

WHAT I S INVERSE GAS CHROMATOGRAPHY ( IGC)?

Inverse Gas Chromatography (IGC)is a gas-phase technique for

characterising surface and bulkproperties of solid materials. Theprinciples of IGC are very simple,being the reverse of a conventionalgas chromatographic (GC)experiment.

A cylindrical column is uniformlypacked with the solid materialof interest, typically a powder,fibre or film. A pulse or constantconcentration of gas is then injecteddown the column at a fixed carrier

gas flowrate, and the time taken for the pulseor concentration front to elute downthe column is measured by a detector.A series of IGC measurements withdifferent gas phase probe moleculesthen allows access to a wide rangeof

physico-chemical properties of the solid

sample.

INTRODUCING THE REVOLUTIONARY SMS iGC

The revolutionary iGC from SMS

is the world’s first commercialinverse gas chromatograph.The unique SMS flow controltechnology* provides the state-of-the-art in humidity controltogether with unrivalled accuracyand reproducibility. The standardinstrument configuration comeswith a thermal conductivity detector (TCD) and a flame ionization detector (FID): this combination allowsdifferentiation between moistureand organic solvent elutants. Further detectors may be added(e.g. Mass Spectrometer) according to customer

requirements.

Single probegas pulse

Packed sample column(particulate or fibre)

INVERSE GAS CHROMATOGRAPHY (IGC)

Single peak(Retention time t )R

Sample gas pulse Standard analytical

column packing

Separated sample peaks

ANALYTICAL GAS CHROMATOGRAPHY

* patent applied for

Advanced instrumentation for the characterisation

of particulates, fibres and thin-films.Opening up a whole new world of

sorption solutions.s

sm

SURFACE

MEASUREMENT

SYSTEMS

GC



Unprecedented Accuracy and RepeatabilityThe combination of 6 electronic mass flowcontrollers, a fixed volume injection loop andisothermal vapour generation means that the SMS

IGC provides an experimental reproducibilitynever before possible with conventional GCinjection systems.

Fully Automated AnalysisThe instrument is operated using IGCWin PCsoftware allowing the selection of up to 10different probe molecules in one experiment andthe consecutive analyses of 2 separate columns.Comprehensive data analysis software brings theresults to your desktop with a few clicks of a mouse.

Quick and Easy Sample PreparationThe use of straight 300mm glass columns with theunique SMS column packer means that a typicalsample can be packed reproducibly in less than

5 minutes. The specially designed quick-changecolumn fittings allow rapid changeover of sampleswhile ensuring the integrity of the column seals.

Flexible and Powerful Characterisation ToolThe SMS IGC instruments are designed withflexibility in mind. A wide range of experimentalpossibilities is available in the standardconfiguration including both pulsed and frontalprobe molecule injection, and the independentcontrol of humidity (%RH) in the carrier gas stream.

The SMS iGC has been designed as a powerfulresearch and QA tool, providing access to manyimportant physicochemical properties of materials.These properties can provide valuable insight intoparticular process or performance-related issues.

Surface Chemistry

Dispersive Surface Energye.g. Pharmaceutical Inhalation Formulation

Specific Polar Interactionse.g. Filtration Characteristics of ActivatedCarbons

Acid-Base Propertiese.g. Surface Characterisation of Catalysts

Surface Adsorption

Isotherms at Low Concentratione.g. Adsorption on Porous Materials

Surface Heterogeneitye.g. Effect of Surface Modification Treatments

Competitive Adsorptione.g. Persistence of Perfumes on Cotton

iGC INSTRUMENT KEY BENEF ITS

iGC SORPT ION SOLUTIONS

P

H A R M

A C

E U T I C A L S

F L

A

V O U

R

I

N

G

S A N D P

E R F UM E S

F I B R E S

M I NERA

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IGC may be used to determine batch-to-batchvariations in surface chemistry which may impactupon the processing or final performance of amaterial. In this example IGC was successfully used

to correlate differences in specific polar interactionsfor three batches of a pure drug material with their corresponding dissolution rates. Batch A gave agood dissolution profile whereas batch C did notand batch B was just outside the accepted tolerance.In this case the much higher specific free energiesmeasured for 1,4 Dioxane and Ethyl Acetate on batchA indicates an increased availability of hydrophilicacidic sites on the surface. This information can beused to explain the differences in surface chemistryand therefore dissolution behaviour of the differentbatches. In this case, the processing of the materialis shown to modify the surface chemistry and hencethe observed dissolution rates.

CASE STUDY 1: BATCH-TO-BATCH VARIAB IL ITY

IGC may also be used to determine the surfaceheterogeneity (distribution of surface sites) ofsingle phases or multicomponent mixtures. Surfaceheterogeneity can have a significant impact uponthe performance and handling of particulatesolids. In this case IGC was used to determine the

heterogeneity profiles of lactose monohydrate,magnesium stearate and a 98%:2% mixture of thetwo materials. The data shows that by adding 2%by weight of magnesium stearate the distribution ofsurface sites available for interaction is significantlyaltered, even though the highest energy sites remainunchanged. These results may be correlated withprocess properties such as powder handling or performance properties such as aerosol dispersion for

example.

CASE STUDY 2: SURFACE HETEROGENEITY IN BINARY MIXTURES

As well as surface properties IGC may also be usedto measure properties of the bulk material suchas glass transition temperatures. In this case thevariation in glass transition temperature (Tg) withrelative humidity (%RH) has been measured byIGC for the complex sugar maltose. The observedlowering of the Tg with increasing %RH can havea dramatic impact upon the storage and processingstability of polymeric materials, in particular thosewith some degree of amorphous character.

CASE STUDY 3: HUMIDITY DEPENDENCE OF GLASS TRANSIT ION TEMPERATURE

Specific interactions on three batches of a pure drugmeasured by IGC

Surface heterogeneity profiles for lactose,magnesium stearate and a 98%:2% mixture of the

Variation of the Tg of Maltose as a function of %RH



Easy to Learn and Use

Realtime Display Of Experiment Progress

Quick-set Methods

Save and Restore Methods

Batch Running of up to 10 Methods

Preconditioning Methods

Wide Range of Method Variables;

Probe Molecule, Temperature, %RH,Flow Rate and Probe Molecule Concentration

User Programmable Probe Molecule Database

Quick and Easy Data Plotting

Raw Data Analysis

Dead-Time Correction

Surface Energy

Heat of Sorption

Isotherm Plotting

%RH / Flow Rate Plot

Performance Test

Elutant Properties Database

Example plots generated using the IGC analysis software running under Microsoft Excel

iGC ANALYS IS SOFTWARE

iGC CONTROL SOFTWARE



Standard Column OvenDual column aluminium block with thermoelectricheating and sub-ambient cooling.Temperature range 5°C – 120°C with 0.1°C stability

Sample Columns300mm x 6mm o.d. dimethyldichlorosilane treatedglass. Internal diameters 2mm, 3mm and 4mm

Probe Molecule OvenForced air circulation type.Temperature range ambient+5°C – 50°C(dependent upon probe molecules used)

Probe Molecule InjectionFixed volume injection loop with electronic massflow controllers. Concentration range 0.02 – 0.95p/pº (dependent upon probe molecules used)

Customised Column Oven on request

Standard DetectorsThermal Conductivity (TCD) and Flame Ionisation

(FID) in series.

Instrument ReproducibilitySpecific component of surface energy <3% standarddeviation.(See Fig. A below for 12 consecutive measurementson the same column packed with paracetamol)

Column-to-Column ReproducibilitySpecific component of surface energy <4% standarddeviation.*(See Fig. B below for single measurements on22 different columns packed with paracetamol)* For a homogeneous material

SMS iGC INSTRUMENT SPECIF ICAT IONS

WORLDWIDE

Surface Measurement Systems Ltd

3 Warple Mews, Warple Way

London W3 0RF

Tel: +44 (0)20 8749 4900

Fax: +44 (0)20 8749 6749

email: [email protected]

www.smsuk.co.uk

For more information on any of the following please contact us:

iGC Sample Analysis

iGC Literature Database

iGC Application Notes

iGC Product Demonstration

SMS Seminars and Workshops

DVS – Dynamic Vapour Sorption

VGI – Vapour Generator Instrument

Confidential Consultancy

Design: Kingfisher Design • Photography: Michael Owen • Illustrations: Andrew Green

USA and CANADA

Surface Measurement Systems, NA

2222 South 12th Street, Suite D

Allentown, PA 18103

Tel: (610) 798 8299

Fax: (610) 798 0334

email: [email protected]

www.smsna.com

Fig. A SMS iGC Instrument Reproducibility Fig. B SMS iGC Column-to-Column Reproducibility

ssm

SURFACE

MEASUREMENT

SYSTEMS

igc brochure 2002

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