Pyrolysis GC with the OPTIC-4Analytical pyrolysis is used to introduce certain sample types to a gas chromatograph, which can only handle compounds in the semi-volatile range. These types include solids and high molecular-weight compounds. Py-GC is also used to minimize sample preparation, or when analysis of a whole sample is desired. Applications for pyrolysis include forensics, paints, ink, art materials, polymers, adhesives, surfactants, and even microorganisms. One of the benefits of pyrolysis is that sample preparation is usually minimal, consisting of trimming and weighing solid samples into a quartz tube or micro vial. Or, liquid samples can be delivered onto a probe or micro vial using a microliter syringe. In both cases, the sample capacity is in the microgram or low milligram range.
Pyrolysis can be done inside the OPTIC-4 inlet liner for both liquid and solid samples.Liquid sample:
The sample is injected into the inlet with any autosampler or in manual mode. The liquid sample is introduced while the inlet is cold, after the injection the solvent is blown away and the OPTIC-4 is heated with a very fast ramp rate to the Pyrolysis temperature.
The sample is placed into the liner or microvial and the liner is placed into the inlet. After this the OPTIC-4 inlet is heated to the pyrolysis temperature. Changing the liners can be done with the LINEX to automate the Pyrolysis.
Different modes are possible e.g. LVI-Pyrolysis, Evolved Gas Analysis (EGA)and Reactive Pyrolysis.
Manual Pyrolysis steps example:
The OPTIC pyrolysis solution has several modes:
With this method or mode the sample is heated after introduction with a fast speed to the pyrolysis temperature. Only one temperature step is used.
Multistep programmed pyrolysis
Analytical runs may be programmed for up to nine temperature steps per sample.
Sample Cup or Micro Vial
A small glass sample cup is available to introduce a sold or liquid sample.
Evolved Gas Analysis (EGA)
The sample is dropped into the inlet which is at a relatively low temperature (ca. 40-100°C). The inlet is then programmed to a much higher temperature (ca. 600°C). Compounds ”evolve” from the sample as the temperature increases. A plot of detector response versus furnace temperature is obtained.
Thermal Desorption (TD)
Thermal desorption is simply a technique for analyzing the constituents evolving from the sample over a given temperature range.
Thermally assisted Hydrolysis and Methylation (THM) can easily be done under Helium conditions.
Thermal Extraction Desorption gas chromatography mass spectrometry (TED-GC-MS). This method consists of thermal extraction of the sample via thermogravimetric analysis (EGA), collection of the evolved gaseous decomposition products on a solid-phase adsorber and analysis of the loaded adsorber using Thermal-Desorption-GC-MS.