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    Application Note: 2017-2: SPT, The "Sample Pre-Concentration Trap" Integrated Concentrator

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    Meriady Meriady
    The SPT (Sample Pre-concentration Trap) integrated into SCION gas chromatographs allows for detection of very low levels of organic compounds in air and gas samples. It works by trapping compounds from a gas sample for several minutes before desorbing the trapped materials onto the GC column for separation and detection. This enables detection of compounds at the low parts per billion level. The SPT has advantages over standalone traps such as a small footprint, direct interfacing to the GC column, and full control from the GC software. It can be used for applications such as detecting impurities in beverage grade CO2 and monitoring BTEX compounds in ambient air at regulatory limits.

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    Application Note: 2017-2: SPT, The "Sample Pre-Concentration Trap" Integrated Concentrator

    Uploaded by

    Meriady Meriady
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    The SPT (Sample Pre-concentration Trap) integrated into SCION gas chromatographs allows for detection of very low levels of organic compounds in air and gas samples. It works by trapping compounds from a gas sample for several minutes before desorbing the trapped materials onto the GC column for separation and detection. This enables detection of compounds at the low parts per billion level. The SPT has advantages over standalone traps such as a small footprint, direct interfacing to the GC column, and full control from the GC software. It can be used for applications such as detecting impurities in beverage grade CO2 and monitoring BTEX compounds in ambient air at regulatory limits.

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    The SPT (Sample Pre-concentration Trap) integrated into SCION gas chromatographs allows for detection of very low levels of organic compounds in air and gas samples. It works by trapping compounds from a gas sample for several minutes before desorbing the trapped materials onto the GC column for separation and detection. This enables detection of compounds at the low parts per billion level. The SPT has advantages over standalone traps such as a small footprint, direct interfacing to the GC column, and full control from the GC software. It can be used for applications such as detecting impurities in beverage grade CO2 and monitoring BTEX compounds in ambient air at regulatory limits.

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    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    88 views3 pages

    Application Note: 2017-2: SPT, The "Sample Pre-Concentration Trap" Integrated Concentrator

    Uploaded by

    Meriady Meriady
    The SPT (Sample Pre-concentration Trap) integrated into SCION gas chromatographs allows for detection of very low levels of organic compounds in air and gas samples. It works by trapping compounds from a gas sample for several minutes before desorbing the trapped materials onto the GC column for separation and detection. This enables detection of compounds at the low parts per billion level. The SPT has advantages over standalone traps such as a small footprint, direct interfacing to the GC column, and full control from the GC software. It can be used for applications such as detecting impurities in beverage grade CO2 and monitoring BTEX compounds in ambient air at regulatory limits.

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    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
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    Application Note: 2017-2

    SPT, the “Sample Pre-concentration


    Trap” integrated concentrator

    Introduction

    The SCION Instruments SPT, Sample Pre-concentration Trap,


    has been available on the market for many years. Originally
    introduced by Varian, recently optimized by SCION Instruments, it
    is still considered unique.
    Many organic compounds present in ambient air are emissions
    from mobile, industrial, or natural sources or landfills and
    hazardous waste sites. The levels of these compounds that are
    detrimental to human health over long time intervals are very low
    or at the low part per billion level and are generally regulated by
    national or local government agencies. The measurement of these
    trace levels generally requires the use of a pre-concentration device air, or a conduit to a stack. The gas sample is pulled through the SPT
    to trap sufficient material from an air sample to allow detection adsorbent or cryogenic trap for several minutes. A sample volume
    with chromatographic detectors. ranging from a few ml to a liter may be sampled. The final volume
    is controlled via the GC method by the electronic micro-pump. The
    Such pre-concentration devices are often standalone units, sample volume is typically between 50 and 150 ml.
    pneumatically interfaced to a gas chromatograph with either
    metallic or fused silica transfer lines and electronically with status After sampling, the SPT is heated to the desorb temperature under
    input and remote operation cables. They are usually controlled stop-flow condition after which the sample is back flushed from the
    from a separate PC or external controller; the complete system will trap onto the capillary column for chromatographic separation of
    occupy quite some bench space. the trapped constituents.
    Built into a SCION Instruments type 456 gas chromatograph the SPT The column is chosen towards the components of interest to be
    has several major advantages over the standalone trapping devices: determined. In many cases this is a methyl-silicone, non-polar
    column; in case of BTEX in air a polar (wax) column is chosen for
    • Complete integration into the gas chromatograph maximum retention of the aromatics and complete separation with
    results in a direct interfacing between the other, non-polar, pollutants.
    pre-concentrator and the GC column,
    The trap itself can be filled with a variety of sorbents, or even with
    • A small footprint mixed fillings extending the applicability of the trap. Our experts
    • Electronically controlled micro sampling pump, flow can help you select the optimal trapping material to match your
    controlled, integrated in the GC chassis. specific application.
    • Full control from CompassCDS, SCION instrument and control
    package.
    Results and Discussion
    • Single vendor approach
    Low level sulphur components in beverage grade CO2
    Instrumentation
    CO2 is a very important and widely used ingredient in many food
    Several configurations have been created and are used in products. Therefore, CO2 quality management is essential for
    different laboratories over the globe. Applications ranging from ensuring consumer satisfaction. CO2 is produced for the food and
    environmental to food. beverage industry as a side product. In the chain of production,
    transport and delivery contaminants may be introduced that could
    A gas sample is drawn from a stainless steel canister, a Tedlar bag,
    have a negative effect on smell or taste. Quality control to identify
    or directly from the source, be it the indoor air, outdoor
    and monitor impurity levels is of extreme importance.
    Figure 1 shows the separation of DME, Acetaldehyde, methanol and
    benzene on a 30 meter wax column after pre-concentration from
    CO2 on a TENAX-GR SPT trap.
    1. DME
    2. Acetaldehyd
    The concentrations are sub ppm for DME and Acetaldehyde, 15 ppm
    3 Methanol
    for methanol and down to 30 ppb for benzene; repeatability ranges 4. Benzene
    from 1 to 1,25%. Total cycle time is 4 minutes.
    A second example, given in Figure 2, concerns a series of sulphur
    components at about 20 ppb in beverage grade CO2. In this case
    the SPT trapping material is glass beads; the GC detector used is the
    PFPD (Pulsed Flame Photometric Detector).

    BTEX in air
    Benzene, Toluene Ethylbenzene and the three Xylene isomers are
    collectively referred to as BTEX. These substances are commonly Figure 1: Impurities in beverage CO2
    found industrial processes as well as exhaust products. Acceptable
    exposure levels are 3 ppb for benzene, 60 ppb for ethylbenzene,
    80 ppb for toluene and 50 ppb for xylenes, as set by environmental
    protection agencies. Monitoring BTEX levels in ambient air, especially
    in rural areas is important for human protection.

    DME Acetaldehyde MeOH Benzene


    run 1 0.170 0.295 16.044 0.027
    run 2 0.168 0.298 16.214 0.027
    run 3 0.171 0.298 16.345 0.027
    run 4 0.175 0.303 16.607 0.028
    run 5 0.170 0.291 16.479 0.027
    Mean 0.171 0.297 16.338 0.027

    Std Dev 0.00 0.00 0.20 0.00 Figure 2: Low Level Sulfur Components, 20 ppb level

    Rsd% 1.25% 1.36% 1.21% 1.02%


    SPT: Tenax GR, 25oC Desorb: 180oC
    Column: BR-SWax, 30m x 0.32 mm, 1 µm film. PN BR89346
    Table 1: Performance characteristics for some impurities in beverage grade
    CO2; concentrations in ppm.everage CO2.

    1 Benzene
    Conclusion 2 Toluene
    3 Ethyl Benzene
    The SCION Instruments SPT (Sample Pre-concentration Trap) is 4 p-Xylene
    5 m-Yylene
    a very powerful tool to help chromatographers to perform low 6 o-Xylene
    7 Chlorobenzene
    level determinations. The applicability ranges from environmental 8 Styrene
    to gas purity. The complete application is integrated into the gas
    chromatograph and fully controlled by CompassCDS.
    As SCION Instruments, we not only control the trap, but can tailor
    the GC configuration to your application. Many different trapping
    materials are available and will be selected towards the application.
    To have all aspects of the analysis in one hand ensures better Figure 3: Aromatics 130 mL, 20 ppbv
    operation flexibility and performance.

    SCION Instruments
    1 Bain Square, Kirkton Campus
    Livington, West Lothian
    EH54 7DQ
    UK
    sales@scioninstruments.com

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