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- Application NotesNote 103: EPA Method 325B, Novel Thermal Desorption Instrument Modification to Improve Sensitivity Note 102: Identification of Contaminants in Powdered Beverages by Direct Extraction Thermal Desorption GC/MS Note 101: Identification of Contaminants in Powdered Foods by Direct Extraction Thermal Desorption GC/MS Note 100: Volatile and Semi-Volatile Profile Comparison of Whole Versus Cracked Versus Dry Homogenized Barley Grains by Direct Thermal Extraction Note 99: Volatile and Semi-Volatile Profile Comparison of Whole vs. Dry Homogenized Wheat, Rye and Barley Grains by Direct Thermal Extraction GC/MS Note 98: Flavor and Aroma Profiles of Truffle Oils by Thermal Desorption GC/MS Note 97: Flavor Profiles of Imported and Domestic Beers by Purge & Trap Thermal Desorption GC/MS Note 96: Reducing Warping in Mass Spectrometer Filaments, with SISAlloy® Yttria/Rhenium Filaments Note 95: Detection of Explosives on Clothing Material by Direct and AirSampling Thermal Desorption GC/MS Note 94: Detection of Nepetalactone in the Nepeta Cataria Plant by Thermal Desorption GC/MS Note 93: Detection of Benzene in Carbonated Beverages with Purge & Trap Thermal Desorption GC/MS Note 92: Yttria Coated Mass Spectrometer Filaments Note 91: AutoProbe DEP Probe Tip Temperatures Note 90: An Automated MS Direct Probe for use in an Open Access Environment Note 89: Quantitation of Organics via a Mass Spectrometer Automated Direct Probe Note 88: Analysis of Silicone Contaminants on Electronic Components by Thermal Desorption GC-MS Note 87: Design and Development of an Automated Direct Probe for a Mass Spectrometer Note 86: Simulation of a Unique Cylindrical Quadrupole Mass Analyzer Using SIMION 7.0. Note 85: Replacing an Electron Multiplier in the Agilent (HP) 5973 MSD Note 84: Vacuum Pump Exhaust Filters - Charcoal Exhaust Traps Note 83: Vacuum Pump Exhaust Filters - Oil Mist Eliminators Note 82: Vacuum Pump Exhaust Filters Note 81: Rapid Bacterial Chemotaxonomy By DirectProbe/MSD Note 80: Design, Development and Testing of a Microprocessor ControlledAutomated Short Path Thermal Desorption Apparatus Note 79: Volatile Organic Compounds From Electron Beam Cured and Partially Electron Beam Cured Packaging Using Automated Short Path Thermal Desorption Note 78: A New Solution to Eliminate MS Down-Time With No-Tool-Changing of Analytical GC Columns Note 77: The Determination of Volatile Organic Compounds in VacuumSystem Components Note 76: Determination of the Sensitivity of a CRIMS System Note 75: An Apparatus for Sampling Volatile Organics From LivePlant Material Using Short Path Thermal Desorption Note 74: Examination of Source Design in Electrospray-TOF Using SIMION 3D Note 73: The Analysis of Perfumes and their Effect on Indoor Air Pollution Note 72: 1998 Version of the NIST/EPA/NIH Mass Spectral Library, NIST98 Note 71: Flavor Profile Determination of Rice Samples Using Shor tPath Thermal Desorption GC Methods Note 70: Application of SIMION 6.0 To a Study of the Finkelstein Ion Source: Part II Note 69: Application of SIMION 6.0 To a Study of the Finkelstein Ion Source: Part 1 Note 68: Use of a PC Plug-In UV-Vis Spectrometer To Monitor the Plasma Conditions In GC-CRIMS Note 67: Using Chemical Reaction Interface Mass Spectrometry (CRIMS) To Monitor Bacterial Transport In In Situ Bioremediation Note 66: Probe Tip Design For the Optimization of Direct Insertion Probe Performance Note 65: Determination of Ethylene by Adsorbent Trapping and Thermal Desorption - Gas Chromatography Note 64: Comparison of Various GC/MS Techniques For the Analysis of Black Pepper (Piper Nigrum) Note 63: Determination of Volatile and Semi-Volatile Organics in Printer Toners Using Thermal Desorption GC Techniques Note 62: Analysis of Polymer Samples Using a Direct Insertion Probe and EI Ionization Note 61: Analysis of Sugars Via a New DEP Probe Tip For Use With theDirect Probe On the HP5973 MSD Note 60: Programmable Temperature Ramping of Samples Analyzed ViaDirect Thermal Extraction GC/MS Note 59: Computer Modeling of a TOF Reflectron With Gridless Reflector Using SIMION 3D Note 58: Direct Probe Analysis and Identification of Multicomponent Pharmaceutical Samples via Electron Impact MS Note 57: Aroma Profiles of Lavandula species Note 56: Mass Spec Maintenance & Cleaning Utilizing Micro-Mesh® Abrasive Sheets Note 55: Seasonal Variation in Flower Volatiles Note 54: Identification of Volatile Organic Compounds in Office Products Note 53: SIMION 3D v6.0 Ion Optics Simulation Software Note 52: Computer Modeling of Ion Optics in Time-of-Flight mass Spectrometry Using SIMION 3D Note 51: Development and Characterization of a New Chemical Reaction Interface for the Detection of Nonradioisotopically Labeled Analytes Using Mass Spectrometry (CRIMS) Note 50: The Analysis of Multiple Component Drug Samples Using a Direct Probe Interfaced to the HP 5973 MSD Note 49: Analysis of Cocaine Utilizing a New Direct Insertion Probe on a Hewlett Packard 5973 MSD Note 48: Demonstration of Sensitivity Levels For the Detection of Caffeine Using a New Direct Probe and Inlet for the HP 5973 MSD Note 47: The Application Of SIMION 6.0 To Problems In Time-of-Flight Mass Spectrometry Note 46: Delayed Extraction and Laser Desorption: Time-lag Focusing and Beyond Note 45: Application of SIMION 6.0 to Filament Design for Mass Spectrometer Ionization Sources Note 44: The Design Of a New Direct Probe Inlet For a Mass Spectrometer Note 43: Volatile Organic Composition In Blueberries Note 42: The Influence of Pump Oil Purity on Roughing Pumps Note 41: Hydrocarbon Production in Pine by Direct Thermal Extraction Note 40: Comparison of Septa by Direct Thermal Extraction Note 39: Comparison of Sensitivity Of Headspace GC, Purge and Trap Thermal Desorption and Direct Thermal Extraction Techniques For Volatile Organics Note 38: A New Micro Cryo-Trap For Trapping Of Volatiles At the Front Of a GC Capillary Column Note 37: Volatile Organic Emissions from Automobile Tires Note 36: Identification Of Volatile Organic Compounds In a New Automobile Note 35: Volatile Organics Composition of Cranberries Note 34: Selection Of Thermal Desorption and Cryo-Trap Parameters In the Analysis Of Teas Note 33: Changes in Volatile Organic Composition in Milk Over Time Note 32: Selection and Use of Adsorbent Resins for Purge and Trap Thermal Desorption Applications Note 31: Volatile Organic Composition in Several Cultivars of Peaches Note 30: Comparison Of Cooking Oils By Direct Thermal Extraction and Purge and Trap GC/MS Note 29: Analysis Of Volatile Organics In Oil Base Paints By Automated Headspace Sampling and GC Cryo-Focusing Note 28: Analysis Of Volatile Organics In Latex Paints By Automated Headspace Sampling and GC Cryo-Focusing Note 27: Analysis of Volatile Organics In Soils By Automated Headspace GC Note 26: Volatile Organics Present in Recycled Air Aboard a Commercial Airliner Note 25: Flavor and Aroma in Natural Bee Honey Note 24: Selection of GC Guard Columns For Use With the GC Cryo-Trap Note 23: Frangrance Qualities in Colognes Note 22: Comparison Of Volatile Compounds In Latex Paints Note 21: Detection and Identification Of Volatile and Semi-Volatile Organics In Synthetic Polymers Used In Food and Pharmaceutical Packaging Note 20: Using Direct Thermal Desorption to Assess the Potential Pool of Styrene and 4-Phenylcyclohexene In Latex-Backed Carpets Note 19: A New Programmable Cryo-Cooling/Heating Trap for the Cryo-Focusing of Volatiles and Semi-Volatiles at the Head of GC Capillary Columns Note 18: Determination of Volatile Organic Compounds In Mushrooms Note 17: Identification of Volatile Organics in Wines Over Time Note 16: Analysis of Indoor Air and Sources of Indoor Air Contamination by Thermal Desorption Note 14: Identification of Volatiles and Semi-Volatiles In Carbonated Colas Note 13: Identification and Quantification of Semi-Volatiles In Soil Using Direct Thermal Desorption Note 12: Identification of the Volatile and Semi-Volatile Organics In Chewing Gums By Direct Thermal Desorption Note 11: Flavor/Fragrance Profiles of Instant and Ground Coffees By Short Path Thermal Desorption Note 10: Quantification of Naphthalene In a Contaminated Pharmaceutical Product By Short Path Thermal Desorption Note 9: Methodologies For the Quantification Of Purge and Trap Thermal Desorption and Direct Thermal Desorption Analyses Note 8: Detection of Volatile Organic Compounds In Liquids Utilizing the Short Path Thermal Desorption System Note 7: Chemical Residue Analysis of Pharmaceuticals Using The Short Path Thermal Desorption System Note 6: Direct Thermal Analysis of Plastic Food Wraps Using the Short Path Thermal Desorption System Note 5: Direct Thermal Analysis Using the Short Path Thermal Desorption System Note 4: Direct Analysis of Spices and Coffee Note 3: Indoor Air Pollution Note 2: Detection of Arson Accelerants Using Dynamic Headspace with Tenax® Cartridges Thermal Desorption and Cryofocusing Note 1: Determination of Off-Odors and Other Volatile Organics In Food Packaging Films By Direct Thermal Analysis-GC-MS Tech No. "A" Note 14: Elimination of "Memory" Peaks in Thermal Desorption Improving Sensitivity in the H.P. 5971 MSD and Other Mass Spectrometers - Part I of II Improving Sensitivity in the H.P. 5971 MSD and Other Mass Spectrometers- Part II of II Adsorbent Resins Guide Development and Field Tests of an Automated Pyrolysis Insert for Gas Chromatography. Hydrocarbon Production in Pine by Direct Thermal Extraction A New Micro Cryo-Trap for the Trapping of Volatiles at the Front of a GC Capillary (019P) - Comparison of Septa by Direct Thermal Extraction Volatile Organic Composition in Blueberry Identification of Volatile Organic Compounds in Office Products Detection and Indentification of Volatiles in Oil Base Paintsby Headspace GC with On Column Cryo-Trapping Evaluation of Septa Using a Direct Thermal Extraction Technique INFLUENCE OF STORAGE ON BLUEBERRY VOLATILES Selection of Thermal Desorption and Cryo-Trap Parameters in the Analysis of Teas Redesign and Performance of a Diffusion Based Solvent Removal Interface for LC/MS The Design of a New Direct Probe Inlet for a Mass Spectrometer Analytes Using Mass Spectrometry (CRIMS) Application of SIMION 6.0 to Filament Design for Mass Spectrometer Ionization Sources A Student Guide for SIMION Modeling Software Application of SIMION 6.0 to Problems in Time-of-flight Mass Spectrometry Comparison of Sensitivity of Headspace GC, Purge and TrapThermal Desorption and Direct Thermal Extraction Techniques forVolatile Organics The Influence of Pump Oil Purity on Roughing Pumps Analysis of Motor Oils Using Thermal Desorption-Gas Chromatography-Mass Spectrometry IDENTIFICATION OF VOLATILE ORGANIC COMPOUNDS IN PAPER PRODUCTS Computer Modeling of Ion Optics in Time-of-Flight mass Spectrometry using SIMION 3D Seasonal Variation in Flower Volatiles Development of and Automated Microprocessor Controlled Gas chromatograph Fraction Collector / Olfactometer Delayed Extraction and Laser Desorption: Time-lag Focusing and Beyond A New Micro Cryo-Trap for the Trapping of Volatiles at the Front of a GC Column Design of a Microprocessor Controlled Short Path Thermal Desorption Autosampler Computer Modeling of Ion Optics in Time-of-Flight Mass Spectrometry Using SIMION 3D Thermal Desorption Instrumentation for Characterization of Odors and Flavors
- AccessoriesTD Supply Kit Desorption Tubes Adsorbent Resins Desorption Tube Needles Desorption Tube Seals Desorption System Fittings GC Cryo-Trap Extraction Cell Wheaton Purge and Trap System TD Sample Loader Prepacked, Conditioned Desorption Tubes Desorption Tube Packing Accessories Stainless Steel Purge Heads Injection Port Liners Tenax TA Poster TD Application Notes Customer Service
- Adsorbent Resins GuideTenax® TA Adsorbent Resin Tenax®-GR Adsorbent Resin for Trapping Volatiles Carbotrap Adsorbent Resin Physical Properties Carbotrap C Adsorbent Resin Physical Properties Carboxen 569 Adsorbent Resin Physical Properties Carbsieve SIII Adsorbent Resin Physical Properties Glass Beads Adsorbent Resin Physical Properties Determination and Use of Breakthrough Volume Data Tenax® TA Breakthrough Volume Chart Tenax® TA Breakthrough Volume Data Tenax® GR Breakthrough Volume Data Carbotrap Breakthrough Volume Data Carbotrap C Breakthrough Volume Data Carboxen 569 Breakthrough Volume Data Carbosieve SIII Breakthrough Volume Data Glass Beads Breakthrough Volume Data Hydrocarbon Breakthrough Volumes for Adsorbent Resins Alcohol Breakthrough Volumes for Adsorbent Resins Alkene Breakthrough Volumes for Adsorbent Resins Acetate and Acid Breakthrough Volumes for Adsorbent Resins Aldehyde and Ketone Breakthrough Volumes for Adsorbent Resins Halogen Breakthrough Volumes for Adsorbent Resins Amine Breakthrough Volumes for Adsorbent Resins Aromatics and Terpenes Breakthrough Volumes for Adsorbent Resins Water Breakthrough Volumes for Adsorbent Resins Tenax® TA Back Pressure Versus Flow Data Tenax® GR Back Pressure Versus Flow Data Carbotrap and Carbotrap C Back Pressure Versus Flow Data Carbosieve SIII Back Pressure Versus Flow Data
- Determination and Use of Breakthrough Volume DataDefinition of Breakthrough Volume Calculation and Use of Breakthrough VolumeData Determination of Breakthrough Volume Example of the Use of Breakthrough Volume Data Determination of Back Pressure Data for Adsorbent Resins How to Select an Adsorbent Resin for an Application Use of Mixed Resin Beds Preparation and Conditioning of Desorption Tubes and ResinBeds Note 32: Selection and Use of Adsorbent Resins for Purge and Trap Thermal Desorption Applications Other References on Adsorbent Resins
- Use of Mixed Resin Beds (This Page)
The selection of an adsorbent resin for an application is based on a large number of variables. These variables originate from three sources and each area and parameter must be evaluated before a resin is selected. The Breakthrough Volume tables are a very useful aid in the selection of a resin or group of resins for a particular application. In many cases one resin will not enable the analysis of all the analytes of interest. This is especially the case when a wide range of boiling point analytes are present in the sample. For example the analysis of a sample that contains very volatile organics such as acetone or butane but also contains very large hydrocarbons. For these applications, mixed bed or multiple bed resins are frequently utilized.
The more appropriate term for these type tubes is probably multiple layer resin beds. A large number of resins are available which can be selected for their ability to trap and release analytes of interest. These resins can be evaluated and selected by using the Breakthrough Volume Tables. Each adsorbent resin has its own unique properties and the ability to trap and release a certain range of organic compounds. Resins such as glass beads are very good for trapping and releasing the very large hydrocarbons (C20 and larger). But volatile analytes and most moderate boilers will pass right through this resin. Tenax® is the most popular resin for the analysis of a wide array of analytes including the aromatics and terpenes. If large hydrocarbons were trapped on this resin it would be near impossible to desorb them off the resin. By the same token the very volatile organics such as propane will pass right through this resin. Carobsieve SIII is the finest of the charcoals for the trapping of the most volatile organics. Even compounds down to ethane can be trapped with this resin. However if any of the larger compounds were trapped on this resin, it would be impossible to release these analytes off the adsorbent resin. The use of multiple layer resin beds permits the trapping and analysis of a wide boiling point range of organics using moderate desorption temperatures.
Due to these unique trapping properties of each resin, it is important that the resins be packed in the correct order as shown above. The resins, such as the charcoals, which trap the smallest analytes should always be the top layer of the multiple layer resin beds. Likewise the resins which trap only the largest molecules and do not retain any of the lighter volatiles (such as the glass beads) must be the bottom layer. When packing these mixed bed resins, it is important that the resins be layered, one on top of the other with minimal mixing of the resins. If the resins were mixed together, the packed desorption tubes would not perform as expected because the most adsorbing of the resin (i.e. the charcoals) would be exposed to the larger molecules during sample loading and would not release these analytes during the thermal desorption process.
Once the multiple layered desorption tubes are packed, they must always be used in the correct orientation. It would be helpful to always mark the charcoal end of the trap. When collecting a sample for analysis it is important that the gas volume being sampled enters the end of the desorption with the least retaining resin (the glass beads end). This will enable the glass beads to adsorb the heavy hydrocarbons and pass all the other analytes. The next layer will adsorb the aromatics and medium boilers and the final charcoal layer will trap the lowest molecular weight compounds. This sample collection direction shown via the blue arrow above must always be used during the sample collection process.
During the thermal desorption process, the direction of gas flow is reversed as shown by the red arrow in the above diagram. By reversing the flow through the desorption tube the large molecular weight compounds are never exposed to the other resins which would trap these compounds and retain them in the resin. This assures complete delivery of all the analytes to the GC injection port for analysis. This reversal of gas flow between sample collection and desorption is good practice not only for multiple layer desorption tubes but even for single layer adsorption tubes. This permits the easiest release of analytes off the adsorbent resin in the trap.
Packing of Multiple Layered Resin Beds
Multiple resin beds are packed much like the single layer resin bed described previously. Glass wool plugs at the ends of the desorption tubes hold the resin bed in place. The resins are added to the desorption tube one layer at a time and care should be taken to minimize the mixing of the resins at the interface of the two resin beds. Another technique is to put a small glass wool plug between each resin bed. This will eliminate the mixing of the resin beds, but it will also take up space within the desorption tube which is needed to hold the resin beds. The packed desorption tubes must be flow conditioned as described previously using care not to exceed the temperature limit of any of the adsorbent resins.