Gas chromatograph and mass spectrometry is commonly utilized in the separation and identification of complex components due to its high resolution and sensitivity. The chromatographic, gas interface, mass spectrometer part (ion source, mass analyzer, detector), and data processing system are the key components of GCMS.

Gas-mass spectrometry (GCMS) is commonly employed in the separation and identification of complex components because of its high resolution and sensitivity. Without the need for sample preparation, GCMS can instantly determine the molecular weight of synthesized molecules.

Composition and fundamental concepts of gas-mass spectrometry (GC/MS)

In mass spectrometry, molecules of matter create charged particles by physical or chemical interactions in a high vacuum, and some of the charged particles can be further broken up. The mass-to-charge ratio (m/z, formerly m/e) of each ion is referred to as the mass-to-charge ratio (m/z). After the ions with different mass-to-charge ratios are separated one by one by the mass separator, the detector measures the mass-to-charge ratio and relative intensity of each ion, and the resulting spectrum is known as a mass spectrum.

Mass spectrometry is an analytical method that ionizes analytes, then separates them based on the ions' mass-to-charge ratio, and achieves the goal of analysis by measuring the peak intensity of the ions. Under certain conditions, macromolecular organic matter follows a certain pyrolysis law, which means that a specific sample can produce specific pyrolysis products and product distribution, and high-performance gas chromatography is used to analyze and identify the pyrolysis products. Original sample, according to this categorization.

The polymer sample is placed in a cracker and rapidly pyrolyzed at high temperature under highly controlled operating conditions to yield volatile tiny molecular products, which are then delivered to a gas chromatograph for separation and analysis. Because the composition and relative amount of broken fragments are directly related to the structure of the polymer to be examined, each polymer's cracking chromatogram has its own features; thus, the cracking chromatogram is also known as the thermal cracking fingerprint chromatogram.

Advantages of GCMS

The high separation efficiency of GCMS

Most pyrolysis gas chromatographs employ capillary chromatographic columns, which are capable of effectively separating complicated pyrolysis products, particularly tiny changes in macromolecular organic molecules and trace components in polymer materials. Reflect fragmentation chromatograms sensitively to locate related features.

High sensitivity

A hydrogen flame ionization detector with high sensitivity is commonly used in pyrolysis gas chromatography (GCMS).

Small sample size

The sample size is typically in the range of micrograms to milligrams, which is extremely useful for detecting just trace materials.

Rapid analysis time

The typical analysis time is 30 minutes.

When the cleavage product is complex, one analysis can take 1 to 2 hours.

A considerable number of information can be obtained

From qualitative and quantitative analysis, as well as the relationship between cracking circumstances and cracking products, the association between sample structure and cracking products, cracking mechanism, and reaction kinetics.

Numerous applications

GCMS can be used on any type of sample that does not require pretreatment. Viscous liquids, powders, fibers, elastomers, and other materials, as well as cured resins, coatings, and vulcanizates, can be directly injected for analysis.

Easy to promote

The pyrolysis injector has a basic structure and can be used for separation and analysis in conjunction with a gas chromatograph.

Can be linked to a variety of spectroscopic instruments

Any spectroscopic equipment that can be linked to a gas chromatograph can also be linked to pyrolysis gas chromatography.

Application of GCMS

It is appropriate for the separation and analysis of chemicals with a high molecular weight, a complicated structure, as well as challenging volatile and insoluble substances. The flash evaporation technique in pharmaceutical analysis can be used to assess the volatile components in Chinese herbal remedies.

The term "flash evaporation" refers to the fast heating of a sample at a lower temperature (lower than the sample's pyrolysis temperature) before cracking it to evaporate the volatile components in order to get a chromatogram. After that, the sample is broken at high temperatures to produce a cracked chromatogram. Important information about volatile components in the sample can be gained in this manner, which is highly useful in qualitative identification of the sample. Polymer identification by pyrolysis-gas chromatography is accomplished by comparing the programs of unknown and standard samples, a process known as "fingerprint" identification. Fingerprints of standard samples can be maintained in a computer database or obtained during identification by doing parallel experiments with unknown samples. The spectra being compared must be obtained under the same experimental conditions, regardless of method. Although the fingerprint identification approach is simple and easy to use, it is not exact, and it can be difficult to appropriately identify some polymers with comparable structures.

Polymer identification can also be accomplished via multidimensional pyrolysis gas chromatography. The cleavage products with the set retention time window on the methyl silicone column are moved to the PEG-20M column for analysis, and the properties of olefin polymers and nylons can be acquired using a methyl silicone and PEG-20M double capillary column system.

There is also an internal standard identification approach, which involves cracking an unknown sample with polystyrene as a reference polymer, determining the retention time of the sample product relative to styrene, and comparing it to the comparable result of the standard sample.

Finally, gas chromatograph and mass spectrometry (GCMS)) is a highly successful approach for identifying polymers. The fingerprint identification method is simple and practical. The approach of identifying characteristic peaks is superior, however structural identification of characteristic peaks is required. Jinjian Laboratory engineers feel that adopting the internal standard approach and recognizing the characteristic peaks can provide certain reliability while avoiding the requirement to define the structure of the characteristic product. The spectral library is a preferable option for comparison because it is convenient and quick.