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Headspace SamplerReasons for Selection

The following points were considered when selecting a headspace sampler.

1) Superior ability to quantitatively analyze samples) !bility to detect trace components with high sensitivity") !bility to analyze low and high boiling point components#) Superior maintainability

1) Superior Quantitative Analysis Capability$%cellent repeatability is essential for quantitative analysis using headspace methods. &f processingsamples with significantly different concentration levels within the same batch' then it is important tominimize carryover in order to obtain reliable quantitative data. !lso' if multiple samples are beingprocessed' then the system must be equipped with a barcode reader or other sample managementfunctionality.Therefore' the HS( headspace sampler includes these important performance and functionalfeatures.

Repeatability:

The HS( achieves high repeatability due to high precision flowrate control provided by an electronicflow controller *!+,) and a mechanism that automatically conveys sample vials from below the oven.This unique sample vial conveyer system minimizes heat loss when conveying sample vials into or outof the oven and helps maintain temperature stability during overlapped analysis.

Carryover:HS( uses independent pressurized and vacuum lines to inhibit carryover. -any competing modelsshare many parts of flow lines for both pressurized and vacuum flows' which increases the ris ofcarryover after analyzing high concentration or polar components.

Barcode Reader:HS(/s user friendly design eliminates operation errors. !lso' a barcode reader is provided to record a

history.

2) High Sensitivity Detection o !race Co"ponents0ue to its fundamental operating principle' static headspace methods offer lower sensitivity thandynamic headspace methods' such as purge and trap methods. evertheless' users still want theability to analyze trace components using static headspace analysis. Therefore' that requires aheadspace system with functionality for concentrating samples' which is also able to switch easilybetween concentrating and normal modes.The HS( is equipped with an electronically cooled trap and can be switched easily to normal mode.

Concentrating Sa"ples:The HS( trap model includes a built(in electronically cooled trap' which enables concentrating

headspace gases for high sensitivity analysis. 0ue to the electronically cooled trap' low boiling pointcompounds can be analyzed using hydrophobic Tena% lines' which means the system can analyzeeverything from low boiling point to high boiling point compounds in samples containing water by firstconcentrating them.+urthermore' method files can be used to easily switch between the trap mode and normal sample loopmode. Trap and loop modes can be freely intermi%ed even within a series of analyses processed inbatches.

#) Analysis o $o% to High Boiling &oint Co"ponentsHeadspace methods are used to analyze 23,s *volatile organic compounds). However' in some casesit is necessary to analyze 223,s *very volatile organic compounds) with lower boiling points or S23,s*semi(volatile organic compounds) with higher boiling points than regular 23,s. Therefore' some userswant the ability to measure components ranging from 223,s to S23,s.

The HS( includes functionality capable of analyzing compounds with this wide range of boiling points.

Analysis o $o% Boiling &oint Co"ponents:The HS( uses a 4eltier element to cool the trap' which means it can be used to analyze low boiling

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point components. ,ompetitor traps are air(cooled' which means traps cannot be cooled below roomtemperature' maing it difficult to concentrate low boiling point components.

Analysis o High Boiling &oint Co"ponents:

HS( vial temperature and sample line temperature can be controlled to settings as high as " ,'

which means it can be used to analyze high boiling point components. &n contrast' the ma%imum

temperature setting on many competitor models is lower than " ,.

') Superior (aintainabilityTo increase the up(time rate of analytical instruments' they must be easy to maintain. &n particular'columns should be easily replaceable by anyone. HS( columns can be replaced using the sameprocedure as used for normal liquid in5ection. +urthermore' sample lines are user replaceable' forcontamination or other reasons.

ase o (aintenance:The HS( is designed to allow performing maintenance tass' such as replacing sample loops orneedles' easily via the top of the instrument. $ven if sample lines become contaminated' such as fromhighly concentrated samples' each line can be replaced individually.The 5oint for the capillary column is the same as for the 6, in5ection unit' which maes replacingcolumns simple. ,onsequently' the HS( is designed to minimize down(time during maintenance and

improve laboratory productivity.